Installation, Operation, and Maintenance IntelliPak ......•• IIff tthheerree iiss aa rriisskk ooff eenneerrggiizzeedd eelleeccttrriiccaall ccoonnttaacctt,, aarrcc,, oorr ffllaasshh,,

SSAAFFEETTYY WWAARRNNIINNGGOnly qualified personnel should install and service the equipment. The installation, starting up, and servicing of heating, ventilating, and air-conditioningequipment can be hazardous and requires specific knowledge and training. Improperly installed, adjusted or altered equipment by an unqualified personcould result in death or serious injury. When working on the equipment, observe all precautions in the literature and on the tags, stickers, and labels thatare attached to the equipment.

April 2020 SSCCXXGG--SSVVXX0011PP--EENN

Installation, Operation, and Maintenance

IntelliPak™ Commercial Self-Contained Modular Series20 to 35 Tons

SSCCWWGG,, SSIIWWGG – 20 to 35 TonSSCCRRGG,, SSIIRRGG – 32 Ton

©2020 Trane SCXG-SVX01P-EN

IntroductionRead this manual thoroughly before operating orservicing this unit.

Warnings, Cautions, and NoticesSafety advisories appear throughout this manual asrequired. Your personal safety and the properoperation of this machine depend upon the strictobservance of these precautions.

The three types of advisories are defined as follows:

WARNINGIndicates a potentially hazardous situationwhich, if not avoided, could result in death orserious injury.

CAUTIONIndicates a potentially hazardous situationwhich, if not avoided, could result in minor ormoderate injury. It could also be used to alertagainst unsafe practices.

NOTICEIndicates a situation that could result inequipment or property-damage onlyaccidents.

Important Environmental ConcernsScientific research has shown that certain man-madechemicals can affect the earth’s naturally occurringstratospheric ozone layer when released to theatmosphere. In particular, several of the identifiedchemicals that may affect the ozone layer arerefrigerants that contain Chlorine, Fluorine and Carbon(CFCs) and those containing Hydrogen, Chlorine,Fluorine and Carbon (HCFCs). Not all refrigerantscontaining these compounds have the same potentialimpact to the environment. Trane advocates theresponsible handling of all refrigerants-includingindustry replacements for CFCs and HCFCs such assaturated or unsaturated HFCs and HCFCs.

Important Responsible RefrigerantPracticesTrane believes that responsible refrigerant practicesare important to the environment, our customers, andthe air conditioning industry. All technicians whohandle refrigerants must be certified according to localrules. For the USA, the Federal Clean Air Act (Section608) sets forth the requirements for handling,reclaiming, recovering and recycling of certainrefrigerants and the equipment that is used in theseservice procedures. In addition, some states ormunicipalities may have additional requirements thatmust also be adhered to for responsible managementof refrigerants. Know the applicable laws and followthem.

WWAARRNNIINNGGPPrrooppeerr FFiieelldd WWiirriinngg aanndd GGrroouunnddiinnggRReeqquuiirreedd!!FFaaiilluurree ttoo ffoollllooww ccooddee ccoouulldd rreessuulltt iinn ddeeaatthh oorrsseerriioouuss iinnjjuurryy..AAllll ffiieelldd wwiirriinngg MMUUSSTT bbee ppeerrffoorrmmeedd bbyy qquuaalliiffiieeddppeerrssoonnnneell.. IImmpprrooppeerrllyy iinnssttaalllleedd aanndd ggrroouunnddeeddffiieelldd wwiirriinngg ppoosseess FFIIRREE aanndd EELLEECCTTRROOCCUUTTIIOONNhhaazzaarrddss.. TToo aavvooiidd tthheessee hhaazzaarrddss,, yyoouu MMUUSSTT ffoolllloowwrreeqquuiirreemmeennttss ffoorr ffiieelldd wwiirriinngg iinnssttaallllaattiioonn aannddggrroouunnddiinngg aass ddeessccrriibbeedd iinn NNEECC aanndd yyoouurr llooccaall//ssttaattee//nnaattiioonnaall eelleeccttrriiccaall ccooddeess..

WWAARRNNIINNGGPPeerrssoonnaall PPrrootteeccttiivvee EEqquuiippmmeenntt ((PPPPEE))RReeqquuiirreedd!!FFaaiilluurree ttoo wweeaarr pprrooppeerr PPPPEE ffoorr tthhee jjoobb bbeeiinngguunnddeerrttaakkeenn ccoouulldd rreessuulltt iinn ddeeaatthh oorr sseerriioouuss iinnjjuurryy..TTeecchhnniicciiaannss,, iinn oorrddeerr ttoo pprrootteecctt tthheemmsseellvveess ffrroommppootteennttiiaall eelleeccttrriiccaall,, mmeecchhaanniiccaall,, aanndd cchheemmiiccaallhhaazzaarrddss,, MMUUSSTT ffoollllooww pprreeccaauuttiioonnss iinn tthhiiss mmaannuuaallaanndd oonn tthhee ttaaggss,, ssttiicckkeerrss,, aanndd llaabbeellss,, aass wweellll aass tthheeiinnssttrruuccttiioonnss bbeellooww::

•• BBeeffoorree iinnssttaalllliinngg//sseerrvviicciinngg tthhiiss uunniitt,,tteecchhnniicciiaannss MMUUSSTT ppuutt oonn aallll PPPPEE rreeqquuiirreedd ffoorrtthhee wwoorrkk bbeeiinngg uunnddeerrttaakkeenn ((EExxaammpplleess;; ccuuttrreessiissttaanntt gglloovveess//sslleeeevveess,, bbuuttyyll gglloovveess,, ssaaffeettyyggllaasssseess,, hhaarrdd hhaatt//bbuummpp ccaapp,, ffaallll pprrootteeccttiioonn,,eelleeccttrriiccaall PPPPEE aanndd aarrcc ffllaasshh ccllootthhiinngg))..AALLWWAAYYSS rreeffeerr ttoo aapppprroopprriiaattee SSaaffeettyy DDaattaaSShheeeettss ((SSDDSS)) aanndd OOSSHHAA gguuiiddeelliinneess ffoorrpprrooppeerr PPPPEE..

•• WWhheenn wwoorrkkiinngg wwiitthh oorr aarroouunndd hhaazzaarrddoouusscchheemmiiccaallss,, AALLWWAAYYSS rreeffeerr ttoo tthhee aapppprroopprriiaatteeSSDDSS aanndd OOSSHHAA//GGHHSS ((GGlloobbaall HHaarrmmoonniizzeeddSSyysstteemm ooff CCllaassssiiffiiccaattiioonn aanndd LLaabbeelllliinngg ooffCChheemmiiccaallss)) gguuiiddeelliinneess ffoorr iinnffoorrmmaattiioonn oonnaalllloowwaabbllee ppeerrssoonnaall eexxppoossuurree lleevveellss,, pprrooppeerrrreessppiirraattoorryy pprrootteeccttiioonn aanndd hhaannddlliinnggiinnssttrruuccttiioonnss..

•• IIff tthheerree iiss aa rriisskk ooff eenneerrggiizzeedd eelleeccttrriiccaallccoonnttaacctt,, aarrcc,, oorr ffllaasshh,, tteecchhnniicciiaannss MMUUSSTT ppuuttoonn aallll PPPPEE iinn aaccccoorrddaannccee wwiitthh OOSSHHAA,, NNFFPPAA7700EE,, oorr ootthheerr ccoouunnttrryy--ssppeecciiffiicc rreeqquuiirreemmeennttssffoorr aarrcc ffllaasshh pprrootteeccttiioonn,, PPRRIIOORR ttoo sseerrvviicciinnggtthhee uunniitt.. NNEEVVEERR PPEERRFFOORRMM AANNYY SSWWIITTCCHHIINNGG,,DDIISSCCOONNNNEECCTTIINNGG,, OORR VVOOLLTTAAGGEE TTEESSTTIINNGGWWIITTHHOOUUTT PPRROOPPEERR EELLEECCTTRRIICCAALL PPPPEE AANNDDAARRCC FFLLAASSHH CCLLOOTTHHIINNGG.. EENNSSUURREEEELLEECCTTRRIICCAALL MMEETTEERRSS AANNDD EEQQUUIIPPMMEENNTT AARREEPPRROOPPEERRLLYY RRAATTEEDD FFOORR IINNTTEENNDDEEDDVVOOLLTTAAGGEE..

SCXG-SVX01P-EN 3

WWAARRNNIINNGGFFoollllooww EEHHSS PPoolliicciieess!!FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonnss bbeellooww ccoouulldd rreessuulltt iinnddeeaatthh oorr sseerriioouuss iinnjjuurryy..

•• AAllll TTrraannee ppeerrssoonnnneell mmuusstt ffoollllooww tthheeccoommppaannyy’’ss EEnnvviirroonnmmeennttaall,, HHeeaalltthh aanndd SSaaffeettyy((EEHHSS)) ppoolliicciieess wwhheenn ppeerrffoorrmmiinngg wwoorrkk ssuucchh aasshhoott wwoorrkk,, eelleeccttrriiccaall,, ffaallll pprrootteeccttiioonn,, lloocckkoouutt//ttaaggoouutt,, rreeffrriiggeerraanntt hhaannddlliinngg,, eettcc.. WWhheerree llooccaallrreegguullaattiioonnss aarree mmoorree ssttrriinnggeenntt tthhaann tthheesseeppoolliicciieess,, tthhoossee rreegguullaattiioonnss ssuuppeerrsseeddee tthheesseeppoolliicciieess..

•• NNoonn--TTrraannee ppeerrssoonnnneell sshhoouulldd aallwwaayyss ffoolllloowwllooccaall rreegguullaattiioonnss..

CopyrightThis document and the information in it are theproperty of Trane, and may not be used or reproducedin whole or in part without written permission. Tranereserves the right to revise this publication at any time,and to make changes to its content without obligationto notify any person of such revision or change.

TrademarksAll trademarks referenced in this document are thetrademarks of their respective owners.

Revision History• Running edits included.

• Updated motor electrical data.

IInnttrroodduuccttiioonn

4 SCXG-SVX01P-EN

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8R-410A Compressors . . . . . . . . . . . . . . . . . . . . . 8

Modular Series Self-Contained UnitComponents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Control Options . . . . . . . . . . . . . . . . . . . . . . . 8Human Interface Panel . . . . . . . . . . . . . . . . 8Unit Control Module . . . . . . . . . . . . . . . . . . 9Optional Controls . . . . . . . . . . . . . . . . . . . . . 9Unit Nameplate . . . . . . . . . . . . . . . . . . . . . . . 9

Model Number Description. . . . . . . . . . . . . . . . 10Commercial Self-Contained ModularSeries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Commercial Self-Contained Air-CooledCondenser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

General Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Pre-Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Receiving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Receiving Checklist. . . . . . . . . . . . . . . . . . . 16Contractor InstallationResponsibilities . . . . . . . . . . . . . . . . . . . . . . 16Unit Inspection . . . . . . . . . . . . . . . . . . . . . . 16

Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Unit Protective Covers. . . . . . . . . . . . . . . . 17Supply Fan Isolators . . . . . . . . . . . . . . . . . 17

Dimensional Data . . . . . . . . . . . . . . . . . . . . . . . . . 19Steam, Hot Water and Electric HeatCoils. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Steam Coils . . . . . . . . . . . . . . . . . . . . . . . . . 23Hot Water Coils . . . . . . . . . . . . . . . . . . . . . . 24Electric Heat Coils . . . . . . . . . . . . . . . . . . . . 25

Plenum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Waterside Economizer . . . . . . . . . . . . . . . . . . . 25

Airside Economizer . . . . . . . . . . . . . . . . . . . . . . 26

Service Clearances . . . . . . . . . . . . . . . . . . . . . . 26

Installation - Mechanical. . . . . . . . . . . . . . . . . . . 28Unit Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Skid Removal . . . . . . . . . . . . . . . . . . . . . . . . 30

Installation Preparation . . . . . . . . . . . . . . . . . . 30Split Apart Unit Assembly . . . . . . . . . . . . 30

Unit Vibration Isolator Option. . . . . . . . . . . . . 31

Unit Isolator InstallationProcedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Duct Connections. . . . . . . . . . . . . . . . . . . . . . . . 32

Installing the Plenum . . . . . . . . . . . . . . . . . . . . 33

Installing the Airside Economizer . . . . . . . . . 33

Water Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Condenser Connections . . . . . . . . . . . . . . 34Condensate Drain Connections. . . . . . . . 34General WatersideRecommendations for CoolingTowers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Waterside Piping Arrangements. . . . . . . 35Water TemperatureRequirements . . . . . . . . . . . . . . . . . . . . . . . 35

Installing Waterside Economizer . . . . . . . . . . 35Waterside Economizer with Left-hand Factory PipingComponents. . . . . . . . . . . . . . . . . . . . . . . . . 36Waterside Economizer with Right-hand Factory PipingComponents. . . . . . . . . . . . . . . . . . . . . . . . . 37

Installating the Hydronic Coil . . . . . . . . . . . . . 38

Refrigerant System . . . . . . . . . . . . . . . . . . . . . . 39Interconnecting Piping . . . . . . . . . . . . . . . 39Preliminary RefrigerantCharging . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Installation - Electrical . . . . . . . . . . . . . . . . . . . . . 42Unit Wiring Diagrams . . . . . . . . . . . . . . . . . . . . 42

Supply Power Wiring . . . . . . . . . . . . . . . . . . . . 42Voltage Range . . . . . . . . . . . . . . . . . . . . . . . 42Voltage Imbalance . . . . . . . . . . . . . . . . . . . 42Phase Monitor . . . . . . . . . . . . . . . . . . . . . . . 42Control Power . . . . . . . . . . . . . . . . . . . . . . . 42

Selection Procedures . . . . . . . . . . . . . . . . . . . . 43

Variable Frequency Drive Option(VFD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Mounting Requirements . . . . . . . . . . . . . . 44Electrical Installation Procedure . . . . . . . 44Variable Frequency Drive WithoutBypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44Variable Frequency Drive WithBypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Table of Contents

SCXG-SVX01P-EN 5

Static Pressure Transducer Installation(VAV units only) . . . . . . . . . . . . . . . . . . . . . . . . . 52

Transducer Location . . . . . . . . . . . . . . . . . 52Installing the Transducer . . . . . . . . . . . . . 52

Installing Electric Heat . . . . . . . . . . . . . . . . . . . 53Electric Heat Coil WiringProcedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Zone Sensor Options for ControlUnits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Standard with All Units:BAYSENS077 . . . . . . . . . . . . . . . . . . . . . . . . 55CV Unit Zone Sensor Options . . . . . . . . . 55

Integrated Comfort Systems Sensors forCV and VAV Applications. . . . . . . . . . . . . . . . . 55

CV and VAV Unit Zone SensorOptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Zone Sensor Installation . . . . . . . . . . . . . . . . . 56Mounting Location . . . . . . . . . . . . . . . . . . . 57Mounting the Subbase . . . . . . . . . . . . . . . 57Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57Standard Remote Sensor(BAYSENS077) . . . . . . . . . . . . . . . . . . . . . . 57

Time Clock Option . . . . . . . . . . . . . . . . . . . . . . . 57Grasslin Time Clock Option . . . . . . . . . . . 57Installing the Time Clock. . . . . . . . . . . . . . 58Surface Mounting Inside Panel . . . . . . . . 58Wiring the Time Clock . . . . . . . . . . . . . . . . 58

Remote Human Interface PanelInstallation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Human Interface (HI) Panel. . . . . . . . . . . . 58Remote Human Interface Panel. . . . . . . . 58Location Recommendations . . . . . . . . . . 59Ambient Temperature and HumidityLimits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Mounting the Remote Human Interface(RHI) Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 59Wall Mounting the RHI Panel. . . . . . . . . . 60

Wiring the Remote Human Interface. . . . . . . 60Low Voltage (AC) Field WiringConnections . . . . . . . . . . . . . . . . . . . . . . . . . 61Interprocessor CommunicationBridge Module Wiring . . . . . . . . . . . . . . . . 61Communication Link (ShieldedTwisted Pair) Wiring. . . . . . . . . . . . . . . . . . 61

At the Self-Contained Unit . . . . . . . . . . . . 61

Connecting to Tracer Summit. . . . . . . . . . . . . 62Communication Wiring. . . . . . . . . . . . . . . 62

Programming the Time ClockOption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Setting the Time Clock. . . . . . . . . . . . . . . . 62Programming the Time Clock . . . . . . . . . 62Reviewing and ChangingPrograms . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Manual Override . . . . . . . . . . . . . . . . . . . . . 63

Operating Principles . . . . . . . . . . . . . . . . . . . . . . . 64Control Sequences of Operation . . . . . . . . . . 64

Occupied/UnoccupiedSwitching . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Field-Supplied Occupied/Unoccupied Input on the RTM. . . . . . . . . 64Tracer Summit System . . . . . . . . . . . . . . . 64Factory-Mounted Time Clock. . . . . . . . . . 64

Unoccupied Sequence of Operation . . . . . . . 64Morning Warm-up . . . . . . . . . . . . . . . . . . . 64Full Capacity Morning Warm-up(MWU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Cycling Capacity Morning Warm-up(MWU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Timed Override Activation—ICS™ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Timed Override Activation—Non-ICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65VAV Drive Max Output . . . . . . . . . . . . . . . 65

Occupied Sequence. . . . . . . . . . . . . . . . . . . . . . 65Occupied Zone Temperature—Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Zone Temperature Control (UnitModel Number Digit 9 = 4 or 5) . . . . . . . . 65Supply Air Temperature Control(Unit Model Number Digit 9 = 1, 2, 3,or 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Units With Economizer . . . . . . . . . . . . . . . 66Cooling/Waterside Economizer. . . . . . . . 66Cooling/Airside Economizer. . . . . . . . . . . 66Mechanical Cooling . . . . . . . . . . . . . . . . . . 66Air-Cooled Units Only . . . . . . . . . . . . . . . . 66Water-Cooled Units Only . . . . . . . . . . . . . 66

TTaabbllee ooff CCoonntteennttss

6 SCXG-SVX01P-EN

Auto Changeover (Units with HeatOnly). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66Occupied Zone Temperature—Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66Electric Heat . . . . . . . . . . . . . . . . . . . . . . . . . 66Hydronic Heat: Hot Water orSteam. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66Supply Air Setpoint Reset (VAV UnitsOnly). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67Reset Based on OutdoorAirTemperature. . . . . . . . . . . . . . . . . . . . . . 67Reset Based on zonetemperature . . . . . . . . . . . . . . . . . . . . . . . . . 67Supply AirTempering (Hot Waterand Steam VAV Units Only) . . . . . . . . . . . 67Daytime Warm-up (Units withSupply Air Temperature ControlOnly). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67Supply AirTempering . . . . . . . . . . . . . . . . 67Changeover . . . . . . . . . . . . . . . . . . . . . . . . . 67

Thermostatic Expansion Valve . . . . . . . . . . . . 67

Compressors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67Compressor Cycling. . . . . . . . . . . . . . . . . . 68Compressor Lead/LagOperation . . . . . . . . . . . . . . . . . . . . . . . . . . . 68Step Control . . . . . . . . . . . . . . . . . . . . . . . . . 68Compressor Safety Devices . . . . . . . . . . . 69Low Ambient CompressorLockout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69Evaporator Coil Frost ProtectionFROSTAT . . . . . . . . . . . . . . . . . . . . . . . . . . . 69Service Valve Option . . . . . . . . . . . . . . . . . 69

Waterside Components . . . . . . . . . . . . . . . . . . 69Water Purge . . . . . . . . . . . . . . . . . . . . . . . . . 70Water Piping Options. . . . . . . . . . . . . . . . . 70Basic Water Piping . . . . . . . . . . . . . . . . . . . 70Intermediate Water Piping . . . . . . . . . . . . 70Water Flow Switch Option . . . . . . . . . . . . 70Water-Cooled Condensers . . . . . . . . . . . . 70Waterside Economizer Option. . . . . . . . . 70Waterside Economizer FlowControl. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71Constant Water Flow withIntermediate Piping . . . . . . . . . . . . . . . . . . 71Variable Water Flow withIntermediate Piping . . . . . . . . . . . . . . . . . . 71

Unit Airside Components. . . . . . . . . . . . . . . . . 71Supply Air Fan . . . . . . . . . . . . . . . . . . . . . . . 71Low Entering Air TemperatureSensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72High Duct TemperatureThermostat . . . . . . . . . . . . . . . . . . . . . . . . . . 72Dirty Filter Sensor Option. . . . . . . . . . . . . 72Low Ambient Sensor (Air-CooledUnits) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72Supply Air Static Pressure Limit . . . . . . . 72Variable Frequency DriveOption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72VFD with Bypass . . . . . . . . . . . . . . . . . . . . . 72Airside Economizer Option . . . . . . . . . . . 72Comparative Enthalpy Control . . . . . . . . 73Airside Economizers with TraqDamper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73Standard Two-Position DamperInterface . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73Airside Economizer Interface. . . . . . . . . . 73Airside Economizer Interface withComparative Enthalpy . . . . . . . . . . . . . . . . 74Air-Cooled Condensers . . . . . . . . . . . . . . . 74

Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75Points List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

RTM Module. . . . . . . . . . . . . . . . . . . . . . . . . 75GBAS Module . . . . . . . . . . . . . . . . . . . . . . . 75ECEM Module . . . . . . . . . . . . . . . . . . . . . . . 75

LCI-I Points List . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Phase Monitor. . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Unit Control Components . . . . . . . . . . . . . . . . 75RTM Module Board—Standard on allUnits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76Compressor Module . . . . . . . . . . . . . . . . . 78Human Interface Module—Standardon all Units . . . . . . . . . . . . . . . . . . . . . . . . . . 78Remote Human Interface ModuleOption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78Waterside Module—Standard on AllWater-cooled Units. . . . . . . . . . . . . . . . . . . 78Heat Module. . . . . . . . . . . . . . . . . . . . . . . . . 78Ventilation Override Module (VOM)Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78Trane CommunicationsModules . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79


SCXG-SVX01P-EN 7

Exhaust/Comparative EnthalpyModule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80Ventilation Control Module(VCM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80Generic Building AutomationSystem Module Option . . . . . . . . . . . . . . . 80Input Devices and SystemFunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Pre-Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86Pre-Startup Checklist. . . . . . . . . . . . . . . . . . . . . 86

Supply Fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Ductwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Water-Cooled Unit Piping . . . . . . . . . . . . . . . . 86

Air-Cooled Units Only . . . . . . . . . . . . . . . . . . . . 86

Units with Hydronic Heat . . . . . . . . . . . . . . . . . 86

Units with Electric Heat . . . . . . . . . . . . . . . . . . 86

Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87Air-Cooled Only . . . . . . . . . . . . . . . . . . . . . . . . . 87

Final Refrigerant Charge . . . . . . . . . . . . . . . . . 88

Startup Procedure . . . . . . . . . . . . . . . . . . . . . . . 89Operating & ProgrammingInstructions. . . . . . . . . . . . . . . . . . . . . . . . . . 89Startup Log. . . . . . . . . . . . . . . . . . . . . . . . . . 89

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91Service Access . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Variable Frequency Drive (VFD) . . . . . . . 91Remote-Mounted VariableFrequency Drive (VFD). . . . . . . . . . . . . . . . 91

Air Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Inspecting and Cleaning the DrainPan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Inspecting and Cleaning the Fan . . . . . . . . . . 92

Supply Fan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93Fan Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93Fan Bearings . . . . . . . . . . . . . . . . . . . . . . . . 93Fan Belt Tension . . . . . . . . . . . . . . . . . . . . . 94Measuring Belt Tension . . . . . . . . . . . . . . 94Adjusting Belt Tension . . . . . . . . . . . . . . . 94

Refrigerant System . . . . . . . . . . . . . . . . . . . . . . 97Refrigerant Leak Test Procedure. . . . . . . 97Brazing Procedures . . . . . . . . . . . . . . . . . . 98System Evacuation Procedures . . . . . . . 98

Compressors . . . . . . . . . . . . . . . . . . . . . . . . . . . 100Scroll Compressor Failure Diagnosisand Replacement . . . . . . . . . . . . . . . . . . . 100

Components . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Cleaning Coil Fin . . . . . . . . . . . . . . . . . . . . . . . 102Inspecting and Cleaning Coils . . . . . . . . 102Steam and Hot Water Coils . . . . . . . . . . 102Refrigerant Coils . . . . . . . . . . . . . . . . . . . . 103Draining the Waterside EconomizerCoil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103Cleaning the Condenser . . . . . . . . . . . . . 103. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103Chemical Cleaning of Condenser andEconomizer Coil . . . . . . . . . . . . . . . . . . . . 104

Piping Components. . . . . . . . . . . . . . . . . . . . . 104Water Valves . . . . . . . . . . . . . . . . . . . . . . . 104Flow Switch . . . . . . . . . . . . . . . . . . . . . . . . 104

Maintenance Periodic Checklists . . . . . . . . . 104Monthly Checklist . . . . . . . . . . . . . . . . . . . 104Semi-Annual Maintenance. . . . . . . . . . . 105Annual Maintenance . . . . . . . . . . . . . . . . 105

Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . 106

System Checks . . . . . . . . . . . . . . . . . . . . . 106

Additional Diagnostic Resources . . . . . . . . . 107

Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . 120


8 SCXG-SVX01P-EN

OverviewNNoottee:: One copy of this document ships inside the

control panel of each unit and is customerproperty. It must be retained by the unit’smaintenance personnel.

This manual describes proper installation, operation,and maintenance procedures for air cooled systems. Bycarefully reviewing the information within this manualand following the instructions, the risk of improperoperation and/or component damage will beminimized. It is important that periodic maintenance beperformed to help assure trouble free operation. Amaintenance schedule is provided at the end of thismanual. Should equipment failure occur, contact aqualified service organization with qualified,experienced HVAC technicians to properly diagnoseand repair this equipment.

This manual covers installation, operation andmaintenance of 20-35 ton Modular Series CommercialSelf Contained products with R-410A refrigerant.

R-410A Compressors• Use crank case heaters which must be energized 24

hours prior to compressor start.

• Contain POE oil which readily absorbs potentiallydamaging moisture from air.

• Control box includes a phase monitor to detectphase loss, line voltage imbalance and reversal.

Refer to previous IOM versions for R-407C and R-22units, or contact your local Trane representative.

Refer to the appropriate IOM for air-cooled condenserCXRC-SVX01*-EN and programming IntelliPak™controls PKG-SVP01*-EN.

Modular Series Self-ContainedUnit ComponentsCommercial self-contained units are complete HVACsystems used in floor-by-floor applications. Units areeasy to install because they feature:

• A single point power connection.

• Factory-installed and tested controls.

• A single water point connection.

• Factory-installed options.

• An internally trapped drain connection.

Evaporator fans are double width, double inlet andforward curved with fixed pitch belt drive assembly.Variable frequency drives are optional. EISA efficiencyopen drip proof (ODP) and totally enclosed fan cooled(TEFC) motor options are available.

Modular self-contained units can ship as split-apartunits for installation ease. Split-apart units ship with a

dry nitrogen charge and require field refrigerantcharging.

Units consist of multiple hermetically sealed 3D scrollcompressors, water-cooled condensers (water-cooledunits only), an evaporator coil, dual forward curvedfans, and control panel. Air-cooled units require aremote air-cooled condenser, model CXRC. Unitcontrols are either electromechanical thermostat ormicroprocessor controls on IntelliPak unit.

Hermetically sealed 3D scroll compressor motorsutilize internal motor protection and time delays toprevent excessive cycling.

Water-cooled condensers are shell and tube type withinternal sub-cooler. Condensers are available asmechanically or chemically cleanable. Evaporator fan isdouble width, double inlet and forward curved with afixed pitch belt drive assembly. Variable frequencydrives are optional. EISA efficiency open drip proof(ODP) and totally enclosed fan cooled (TEFC) motoroptions are available.

Package water-cooled units ship with full refrigerantand compressor oil charge. Split apart water cooled,and air cooled, units ship with dry nitrogen charge andcomplete compressor oil charge.

Split apart water cooled units require field connectionof suction and liquid lines. Air-cooled units requirefield-piping discharge and liquid lines to remote aircooled condenser.

All units have two (2) refrigerant circuits that includefilter drier (field-installed in air cooled), liquid lineservice valve, sight glass/moisture indicator, thermalexpansion valve with a sensing bulb and externalequalizing line, suction and discharge line access ports,and high and low pressure cutout switches. Water-cooled units also include pressure relief valve. Aircooled units include liquid line solenoid valve anddischarge line check valve.

Control OptionsUnits may be ordered with conventional thermostatinterface or IntelliPak™ Direct Digital Control (DDC).The controls include a human interface (HI) panel withtwo line by forty character clear English display foreasy operator interface to unit setup and controlparameters. All basic setup parameters are preset fromfactory.

Human Interface PanelThe HI is unit mounted and accessible without openingthe unit’s front panel. It allows easy setpointadjustment using the HI keypad. In addition, the HIdisplays all unit operating parameters and conditionsin a clear language display, which can be configuredfor either English, French, or Spanish.

SCXG-SVX01P-EN 9

The optional remote human interface (RHI) will controlup to four self-contained units, each containing aninterprocessor communications bridge (IPCB). It has allthe same features as the unit-mounted HI except for theservice mode.

For more information on setpoint defaults and rangesand unit programming, see the Self-ContainedProgramming Guide, PKG-SVP01*-EN. A copy shipswith each unit.

Unit Control ModuleThe UCM provides “smart” unit control with safetyfeatures and control relays for pumps, dampers, etc.These modules are referred to as unit control modules(UCM). In this manual, the acronym UCM refers to theentire control system network.

These modules perform specific unit functions usingproportional/integral control algorithms. They aremounted in the unit control panel and are factory wiredto their respective internal components. Each modulereceives and interprets information from other unitmodules, sensors, remote panels, and customer binarycontacts to satisfy the applicable request; i.e.,economizing, mechanical cooling, heating, ventilation.

See the Owner’s section of this manual for a detaileddescription of each module’s function.

Optional ControlsOptional controls include a disconnect switch, dirtyfilter switch, water flow switch (water-cooled only),supply air temperature reset, or external setpointinputs. Daytime heating is available on units withelectric, steam, or hot water heat control options.Morning warm-up operation is available on all units.

The static pressure probe, zone night heat/morningwarm-up, supply air temperature reset sensor optionsship separate inside the unit control panel for fieldinstallation. For more detailed information on the unitcontrol options, see the Owner’s section of thismanual.

Unit NameplateThe unit nameplate identifies the unit model number,appropriate service literature, and wiring diagramnumbers. It is mounted on the left end of the unitcontrol panel.

Figure 1. IntelliPak CSC Modular Series Unit

OOvveerrvviieeww

10 SCXG-SVX01P-EN

Model Number DescriptionCommercial Self-Contained Modular Series

Digit 1 — Unit Model

S = Self-Contained

Digit 2 — Unit Type

C = CommercialI = Industrial

Digit 3 — Condenser Medium

W =Water-cooledR = Remote Air-cooled

Digit 4 — Development Sequence

G =Modular Series

Digit 5— Refrigerant CircuitConfigurationU = Independent, R-410A refrigerant

Digit 6, 7 — Unit Nominal Capacity

20 = 20 Tons (water-cooled only)25 = 25 Tons (water-cooled only)30 = 30 Tons (water-cooled only)32 = 32 Tons (air—cooled only)35 = 35 Tons (water-cooled only)

Digit 8 — Unit Voltage

6 = 200 volt/60 hz/3 ph4 = 460 volt/60 hz/3 ph5 = 575 volt/60 hz/3 ph

Digit 9 — Air Volume/Temp Control

2 = IPak & VFD & supply air temp ctrl3 = IPak & VFD w/ bypass & supply air temp ctrl4 = IPak w/o vol. ctrl, w/ zone temp cool5 = IPak w/o vol. ctrl, w/ zone temp heat/cool6 = IPak w/o vol. ctrl, w/ supply air temp ctrl8 = thermostat interface

Digit 10, 11— Design Sequence

** = Factory Assigned

Digit 12— Unit Construction

A = Vertical dischargeB = Vertical discharge with double wallC = Horizontal dischargeD = Horizontal discharge with double wallE = Vertical discharge, ship separateF = Vertical discharge with double wall, shipseparateG = Horizontal discharge, ship separateH = Horizontal discharge with double wall, shipseparate

Digit 13— Flexible HorizontalDischarge Plenum TypeB = STD plenum w/ factory-cut holesC = Low plenum w/ factory-cut holesE = Std plenum w/ field-cut holesF = Low plenum w/ field-cut holesH = STD plenum double wall (perf) w/ field-cut holesJ = Low plenum double wall (perf) w/ field-cut holesL = STD plenum w/factory-cut holes, shipseparateM = Low plenum w/factory-cut holes, shipseparateP = STD plenum w/field-cut holes, shipseparateR = Low plenum w/field-cut holes, shipseparateU = STD plenum double-wall perf w/field-cutholes, ship separateV = Low plenum double-wall perf w/field-cutholes, ship separate0 =Without Plenum

Digit 14—Motor Type

2 = ODPmotor4 = TEFC motor

Digit 15, 16—Motor HP

05 = 5 hp07 = 7.5 hp10 = 10 hp15 = 15 hp20 = 20 hp25 = 25 hp

Digit 17, 18, 19 – Fan rpm

085 = 850 rpm090 = 900 rpm095 = 950 rpm100 = 1000 rpm105 = 1050 rpm110 = 1100 rpm115 = 1150 rpm120 = 1200 rpm125 = 1250 rpm130 = 1300 rpm135 = 1350 rpm140 = 1400 rpm145 = 1450 rpm150 = 1500 rpm155 = 1550 rpm160 = 1600 rpm165 = 1650 rpm170 = 1700 rpm175 = 1750 rpm180 = 1800 rpm185 = 1850 rpm

Digit 20—Heating Type

A = Steam coil, LHB = Hot water coil, LHC = Electric heat, 1 stageF = Hydronic heat ctrl interfaceG = Elec. heat ctrl interface (Not ULApproved)K = Steam coil ship separate, LHL = Hot water coil ship separate, LHM = Steam coil, RHN = Hot water coil, RHP = Steam coil ship separate, RHR = Hot water coil ship separate, RHT = Hi-cap. hot water coil, LHU = Hi-cap hot water coil, LH, ship separateV = Hi-cap hot water coil, RHW = Hi-cap hot water coil, RH, ship separate0 = None

Digit 21— Unit Isolators

A = IsopadsB = Spring isolators0 = None

Digit 22— Unit Finish

1 = Paint - Slate Gray

Digit 23

0 = None

Digit 24— Unit Connection

1 = Disconnect switch2 = Terminal block3 = Dual point power

Digit 25— Industrial Options

A = Protective coated evaporator coilB = Silver solderC = Stainless steel screwsD = A and BE = A and CF = B and CG = A, B, and C0 = none

Digit 26— Drain PanType

A = Galvanized slopedB = Stainless steel sloped

SCXG-SVX01P-EN 11

Digit 27—Waterside Economizer

A =Mechanical clean full capacity (4-row)B =Mechanical clean low capacity (2-row)C = Chemical clean full capacity (4-row)D = Chemical clean low capacity (2-row)E = Mechanical clean full capacity(4-row)ship separateF = Mechanical clean low capacity (2-row)ship separateG = Chemical clean full capacity (4-row) shipseparateH = Chemical clean low capacity (2-row) shipseparate0 = None

Digit 28— Ventilation Control

B = Airside econ w/Traq™ damper (top O/Ainlet)C = Airside econ w/ std damper, (top O/Ainlet)E = Airside econ w/Traq™ damper andcomparative enthalpy (top O/A)F = Airside econ w/ std dampers andcomparative enthalpy (top O/A)H = None/ventilation for 2-position controlinterfaceJ = Airside economizer interfaceK = Airside economizer interface w/comparative enthalpy0 = None

Digit 29—Water Piping

A = RH condenser connectionB = LH condenser connectionC = RH basic pipingD = LH basic pipingE = RH Intermediate pipingF = LH intermediate pipingJ = RH basic w/ flow switchK = LH basic w/ flow switchL = RH intermediate w/ flow switchM = LH intermediate w/ flow switch0 = None

Digit 30— Condenser Tube Type

A = Standard condenser tubesB = 90/10 CuNi condenser tubes0 = None

Digit 31— Compressor Service Valves

1 =With service valves0 = None

Digit 32—Miscellaneous SystemControl1 = Time Clock2 = Interface For remote HI (IPCB)3 = Dirty filter switch4 = 1 and 25 = 1 and 36 = 2 and 37 = 1, 2 and 30 = None

Digit 33 — Control Interface Options

A = Generic BAS Module; 0-5 VDC (GBAS)B = Ventilation Override Module (VOM)D = Remote Human Interface (RHI)G = GBAS and VOMH= GBAS and RHIJ = VOM and RHIM = GBAS, VOM, and RHIN = BACnet Communications Interface (BCI)P = BCI and GBASQ = BCI and VOMR = BCI and RHIT= BCI and GBAS and VOMU= BCI and GBAS and RHIV= BCI and VOM and RHIW = BCI and GBAS and VOM and RHI0 = None1 = LonTalk Comm5 Interface (LCI)2 = LCI and GBAS3 = LCI and VOM4 = LCI and RHI5 = LCI and GBAS and VOM6 = LCI and GBAS and RHI7 = LCI and VOM and RHI8 = LCI and GBAS and VOM and RHI

Digit 34— Agency

U= UL agency listing0 = None

Digit 35— Filter Type

1 = 2-inch construction throwaway2 = 2-inch med eff. throwaway

Digit 36—Miscellaneous ControlOptionA = Low entering air temp. protect device(LEATPD)B = High duct temp t-statC= Plenum high static switchD = Kit for heat mode output (w/t’stat)E= A and BF= A and CG = B and CH= A, B, and C0 = None

MMooddeell NNuummbbeerr DDeessccrriippttiioonn

12 SCXG-SVX01P-EN

Commercial Self-Contained Air-Cooled Condenser

Digit 1 — Unit Model

C = Condenser

Digit 2 — Unit Type

C = CommercialI = Industrial

Digit 3 — Condenser Medium

R = Remote

Digit 4 — Development Sequence

C = C

Digit 5, 6, 7 — Nominal Capacity

020 = 20 Tons029 = 29 Tons032 = 32 Tons

Digit 8 — Unit Voltage

4 = 460 Volt/60 Hz/3 ph5 = 575 Volt/60 Hz/3 ph6 = 200 Volt/60 Hz/3 ph

Digit 9 — Control Option

0 = No Low Ambient, IPakA = No Low Ambient, T-Stat*B = Low Ambient, IPakC = Low Ambient, T-Stat*

Note: *T-Stat only available on SCRG.

Digit 10, 11—Design Sequence

** = Factory Assigned

Digit 12— Unit Finish

1 = Paint — Slate Gray

Digit 13— Coil Options

A = Non-Coated AluminumC = Protective Coating Aluminum

Digit 14— Unit Isolators

0 = NoneA = Spring IsolatorsB = Isopads

Digit 15— Panels

1 = Louvered Panels

Digit 16— Agency

0 = NoneU =With UL Listing

MMooddeell NNuummbbeerr DDeessccrriippttiioonn

SCXG-SVX01P-EN 13

General Data

Table 1. SCWG/SIWG/SCRG/SIRG general data

Unit Size

Water-Cooled Units Air-Cooled Units

20 25 30 35 32

Compressor Data

Quantity 2 2 1/1 2 2

Nominal Ton/Comp 10 10 10/15 15 15

Circuits 2 2 2 2 2

Evaporator CoilData

Rows 4 4 4 4 4

Sq. Ft. 25.0 25.0 25.0 25.0 25.0

FPF 144 144 144 144 144

Condenser Data

Minimum GPM w/oEcon 36 36 46 54 N/A

Minimum GPM w/Econ 41 41 60 65 N/A

Maximum GPM 80 80 102 119 N/A

Evaporator FanData

Quantity 2 2 2 2 2

Size (Dia. x width -inches) 12-5/8" x 8" 12-5/8" x 9" 12-5/8" x 11" 12-5/8 x 11" 12-5/8" x 11"

Minimum HP 5 5 5 5 5

Maximum HP 20 25 25 25 25

Minimum Design CFM 6350 7250 7250 7250 7250

Maximum DesignCFM 8500 10,625 12,750 14,875 13600

R-410A RefrigerantData RefrigerantCharge - lb (kg)

Circuit A 26.5 (10.9) 27 (12.3) 24.5 (11.1) 23.0 (10.4) See Note 2

Circuit B 26.5 (10.9) 27 (12.3) 23.0 (10.4) 23.0 (10.4) See Note 2

Capacity Steps - % 100/53/0 100/53/0 100/65/42/0 100/53/0 100/53/0

Filter Data

Quantity 4 4 4 4 4

Size (inches) 16 x 25 x 2 16 x 25 x 2 16 x 25 x 2 16 x 25 x 2 16 x 25 x 2

Quantity 4 4 4 4 4

Size (inches) 20 x 25 x 2 20 x 25 x 2 20 x 25 x 2 20 x 25 x 2 20 x 25 x 2

14 SCXG-SVX01P-EN

Table 1. SCWG/SIWG/SCRG/SIRG general data (continued)

Unit Size

Water-Cooled Units Air-Cooled Units

20 25 30 35 32

CCRC/CIRCCondenser Match N/A N/A N/A N/A 32

Notes:1. Compressors are Trane 3-D™ scroll.2. All units operate with R-410A. Water Cooled units that ship together ship with full operating charge. Air-cooled and ship-separate water-cooled

units ship with dry nitrogen charge. Field refrigerant system charge required. Refer to the following table for refrigerant amounts required forremote air-cooled unit and matching CxRC condenser.

3. Maximum cfm limits are set to prevent moisture carryover on the evaporator coil.4. Minimum cfm limits are set to ensure stable thermal expansion valve operation at low load conditions.5. Filter sizes are for units without hot water or steam heating coils.

Table 2. SCRG/SIRG self-contained and CCRC/CIRC remote air-cooled condenser

SCRG/SIRG & CCRC/CIRCUnit Size 32/32

No. of Refrigerant Circuits 2

Operating Charge - lbs R-410A 46/46

Operating Charge - kg R-410A 20.9/20.9

Cond. Storage Cap. - lbs R-410A 51/51

Cond. Storage Cap. - kg R-410A 23.1/23.1

Notes:1. Refrigerant charges are listed as circuit 1/circuit 2 and provide only an estimate. Final charge requires sound field charging practice.2. Operating charge estimate includes the air-cooled self-contained, remote air-cooled condenser, and 25 feet of interconnecting refrigerant piping.3. At conditions of 95°F (35°C), condenser storage capacity is 95% full.4. To determine the correct amount of refrigerant needed for a particular application, reference the Trane Reciprocating Refrigeration Manual.5. Field piping over 25 feet requires additional refrigerant. See Table 22, p. 40 and Table 23, p. 41 to determine amounts.

Table 3. SCWG/SIWG/SCRG/SIRG self-contained heating coil

Filter Data for Heating Coil

Quantity 4

Size (inches) 20 x 18x 2

Size (mm) (508 x 457 x 51)

Quantity 8

Size (inches) 20 x 20 x 2

Size (mm) (508 x 508 x 51)

Coil Data Type Rows No.Size (in) No.Size (mm) fpf

Steam Coil NS 1 224 x 58 2609.6 x 1473.2 42

Hot Water Coil, std. cap 5W 1 148 x 62 11219 x 1575 80

Hot Water Coil, hi-cap. 5W 2 148 x 62 11219 x 1575 108

Notes:1. Hot water and steam heating coils have Prima-Flo® fins and do not have turbulators.2. For coil capacities, use TOPSS™ (Trane Official Product Selection Program).

GGeenneerraall DDaattaa

SCXG-SVX01P-EN 15

Table 4. Waterside economizer coil physical data—SCXG 20, 25, 30, 35

Type Rows FPF Height (in) Length (in)

Chemically Cleanable 2 108 50 72

Mechanically Cleanable 2 108 50 72

Chemically Cleanable 4 108 50 72

Mechanically Cleanable 4 108 50 72

Table 5. CCRC/CIRC remote air-cooled condenser general data

Unit Size 20 29 32

Condenser Fan Data

Number/Type/Drive 4/Prop/Direct 4/Prop/Direct 4/Prop/Direct

Size (inches) 26 26 26

HP ea. 1 1 1

Nominal cfm 18,800 21,200 32,000

Condenser Coil Data

Circuit 1 Size (in.) 1/46 x 71 1/46 x 71 1/64 x 71

Circuit 2 No./Size (in.) 1/46 x 71 1/64 x 71 1/64 x 71

Face Area (sq. ft.) 45.4 54.2 63.1

Rows/fpf 4/144 4/144 4/144

Ambient Temperature Operating Range

Standard Ambient (°F) 50-115 50-115 50-115

Low Ambient Option (°F) 0-115 0-115 0-115

GGeenneerraall DDaattaa

16 SCXG-SVX01P-EN

Pre-InstallationReceivingReceiving ChecklistComplete the following checklist immediately afterreceiving unit shipment to detect possible shippingdamage:

• Inspect individual cartons before accepting. Checkfor rattles, bent carton corners, or other visibleindications of shipping damage.

• If a unit appears damaged, inspect it immediatelybefore accepting the shipment. Make specificnotations concerning the damage on the freight bill.Do not refuse delivery.

• Inspect the unit for concealed damage before it isstored and as soon as possible after delivery.Report concealed damage to the freight line withinthe allotted time after delivery. Check with thecarrier for their allotted time to submit a claim.

• Do not move damaged material from the receivinglocation. It is the receiver’s responsibility to providereasonable evidence that concealed damage didnot occur after delivery.

• Do not continue unpacking the shipment if itappears damaged. Retain all internal packing,cartons, and crate. Take photos of damagedmaterial if possible.

• Notify the carrier of the damage immediately byphone and mail. Request an immediate jointinspection of the damage by the carrier andconsignee.

NNoottee:: Notify your Trane representative of the damageand arrange for repair. Have the carrier inspectthe damage before making any repairs to theunit.

Ship-Separate AccessoriesField-installed sensors ship separately inside maincontrol panel of the unit. Extra filters, sheaves, andbelts ship in the fan motor section of the unit.Condenser plugs, spring isolators, and Iso-pads shipstored in the bottom left side of the unit.

Contractor Installation ResponsibilitiesComplete the following checklist before beginning finalunit installation:

• Verify the unit size and tagging with the unitnameplate.

• Make certain the floor or foundation is level, solid,and sufficient to support the unit and accessoryweights. Level or repair the floor before positioningthe unit if necessary.

• Allow minimum recommended clearances forroutine maintenance and service. Allow space at

end of the unit for shaft removal and servicing.Refer to the unit submittals for dimensions. Seealso the “Service Clearances” section in theDimensional Data chapter.

• Allow three fan diameters above the unit for thedischarge ductwork. Return air enters the rear ofthe unit and conditioned supply air dischargesthrough the top.

• Electrical connection knockouts are on the top, leftside of the unit.

• Allow adequate space for piping access and panelremoval. Condenser water piping, refrigerantpiping, and condensate drain connections are onthe lower left end panel.

NNoottee:: Unit height and connection locations willchange if using vibration isolators. The unitheight may increase up to 5-7/8” with springtype isolators.

• Electrical supply power must meet specific balanceand voltage requirements as described in chapter“Electrical Installation”.

• Water-cooled units only: The installer is responsiblefor providing a condenser main, standby waterpump, cooling tower, pressure gauges, strainers,and all components for waterside piping. See“Water Piping,” p. 34 for general watersiderecommendations.

• Air-cooled units only: The installer is responsiblefor providing and installing the remote air-cooledcondenser and refrigerant piping.

Unit InspectionTo protect against loss due to damage incurred intransit, perform inspection immediately upon receipt ofthe unit.

Exterior InspectionIf the job site inspection reveals damage or materialshortages, file a claim with the carrier immediately.Specify the type and extent of the damage on the bill oflading before signing. Notify the appropriate salesrepresentative.

IImmppoorrttaanntt:: Do not proceed with installation of adamaged unit without salesrepresentative’s approval.

• Visually inspect the complete exterior for signs ofshipping damages to unit or packing material.

• Verify that the nameplate data matches the salesorder and bill of lading.

• Verify that the unit is properly equipped and thereare no material shortages.

• Verify that the power supply complies with the unitnameplate specifications.

SCXG-SVX01P-EN 17

Inspection for Concealed DamageVisually inspect the components for concealed damageas soon as possible after delivery and before it isstored.

If concealed damage is discovered:

• Notify the carrier’s terminal of the damageimmediately by phone and by mail.

• Concealed damage must be reported within 15days.

• Request an immediate, joint inspection of thedamage with the carrier and consignee.

• Stop unpacking the unit.

• Do not remove damaged material from receivinglocation.

• Take photos of the damage, if possible.

• The owner must provide reasonable evidence thatthe damage did not occur after delivery.

RepairNotify the appropriate sales representative beforearranging unit installation or repair.

IImmppoorrttaanntt:: Do not repair unit until the damage hasbeen inspected by the carrier’srepresentative.

UnpackingCommercial self-contained units ship assembled withprotective coverings over the coil and dischargeopenings.Figure 2, p. 17 illustrates a typical shippingpackage.

Unit Protective CoversRemove shipping protection coverings from humaninterface panel (HI) at control panel, filter box (or airinlet opening), discharge air opening, and optionalvariable frequency drive (VFD).

Supply Fan IsolatorsRemove the shipping channels and four fan mountingbolts from beneath the fan. Open both fancompartment doors to access the channels.

While keeping the fan mounting frame level, turn thefan isolator height adjusting bolts clockwise until thefan housing P-gasket compresses 1/4” against the rooftransition piece as shown below.

IImmppoorrttaanntt:: Do not over-compress the P-gasket.

NNoottee:: All Modular units use neoprene isolators.

Figure 2. Typical unit mounting on shipping skid

PPrree--IInnssttaallllaattiioonn

18 SCXG-SVX01P-EN

Figure 3. Fan Isolator Locations

Figure 4. Supply fan horizontal isolation shipping bracket

PPrree--IInnssttaallllaattiioonn

SCXG-SVX01P-EN 19

Dimensional DataFigure 5. SCWG/SIWG (in.)

20 SCXG-SVX01P-EN

Figure 6. SCRG/SIRG (in.)

DDiimmeennssiioonnaall DDaattaa

SCXG-SVX01P-EN 21

Figure 7. SCRG/SIRG/SCWG/SIWG detail “A” (in.) NNoottee:: When unit is ordered with horizontal supply,ensure that all applicable codes are consideredwhen installing equipment. Special attentionshould be made to over head clearances of unit/ducting to meet code requirements.

Table 6. Detail dimensions (in.)

Model A B C D E FSCWG 20 20 10-3/4 58-1/2 5-1/8 13-1/4 11-1/2

SCWG 25 19-1/4 12-1/4 57-5/8 5-1/8 13-1/4 11-1/2SCWG 30 - 35SCRG 32 18 14-5/8 56-1/2 5-1/8 13-1/4 11-1/2

Figure 8. Detail “B” discharge options (in.)


22 SCXG-SVX01P-EN

Figure 9. CCRC/CIRC air-cooled condenser

B

C

REFRIGERANT CIRCUIT 2

REFRIGERANT CIRCUIT 1

(LIQUID LINE CONNECTION REFRIG. CIRCUIT 1)

(HOT GAS CONNECTION REFRIG. CIRCUIT 1)

(LIQUID LINE CONNECTION REFRIG. CIRCUIT 2)

(HOT GAS CONNECTION REFRIG. CIRCUIT 2)

SUPPLY VOLTAGE WIRE ENTRY HOLESIZED FOR 1” CONDUIT

115 VOLT WIRE ENTRY HOLE SIZED FOR3/4” CONDUIT

OPTIONAL LOWAMBIENT DAMPER

REFRIGERANTLINE

24 VOLT WIRE ENTRY HOLE SIZEDFOR 3/4” CONDUIT

CONNECTIONS

OPTIONAL LOW

FRONTAL VIEW

AMBIENT DAMPER(ONE DAMPER PERCIRCUIT)

AA

AB

AC

Table 7. CCRC/CIRC air-cooled condenser dimensions& weight (in. and lbs.)

Model AA AB ACShipWeight

OperatingWeight

CCRC/CIRC 20 70-1/8 88 88 2030 1906CCRC/CIRC 29 70-1/8 88 88 2084 1960CCRC/CIRC 32 70-1/8 88 88 2138 2014

Table 8. CCRC/CIRC electrical connections (in.)

Model E F GCCRC/CIRC 20-32 4-1/2 10-1/2 17-1/2

Table 9. CCRC/CIRC refrigerant connections (in.)

Model E F G H J K L M NCCRC/CIRC 20-32 66-7/8 14-3/8 18-1/2 24-3/4 29 5/8 7/8 5/8 7/8


SCXG-SVX01P-EN 23

Steam, Hot Water and ElectricHeat CoilsSteam CoilsFigure 10. Steam coil: left connections

53 13/16"

36 15/16"

22 1/2"

3 5/16"

15 7/8"1"

40 15/16"

3 7/8"

9 3/8"

6 3/4"16 15/16"

35"

CONDENSER

1 1/2" NPTIFITTINGS

ELECTRICALCONNECTIONS30 7/8"

2 1/8"

92 3/4"73 1/2"

14 9/16" 64 1/2"

VERTICALDISCHARGE

TOP VIEW

LEFT VIEW

3/4" (4X) ISOLATORMOUNTING LOCATIONON BOTTOM OF UNIT

11"

Note: Steam Coil Weight 460 Lbs.

Figure 11. Steam coil: right connections

40 15/16"

53 13/16"22 1/2"

3 5/16"

15 7/8"1"

36 15/16"

3 7/8"

9 3/8"6 3/4"

16 15/16"

35"

PIPING CONNECTIONS2 1/2" NPTE

FEMALE CONNSTEAM INLET 1"

CONDENSATE RETURN TRAP1 1/2" FEMALE CONN

CONDENSATE RETURN TRAP1" FEMALE CONN

VACUUM BREAKER 1"FEMALE CONN

VACUUM BREAKER 1"FEMALE CONN

30 7/8"

2 1/8"

92 3/4"73 1/2"

10 15/16"64 1/2"11"

DISCHARGEVERTICAL

3/4" (4X) ISOLATORMOUNTING LOCATIONON BOTTOM OF UNIT

RIGHT VIEW

TOP VIEW Note: Steam Coil Weight 460 Lbs.


24 SCXG-SVX01P-EN

Hot Water CoilsFigure 12. Hot water coil: left-hand connections

Figure 13. Hot water coil: right-hand connections

Table 10. Hot water coil dimensions & weight (in)(lbs)

Coil A B C D E F G H J K Weight

One Row 53-3/4 4-7/8 73-1/2 16-5/8 6-3/4 7-1/2 23-1/8 37-1/4 1-3/4 2-1/2 415

Two Row 53-3/4 5-1/8 73-1/2 16-5/8 6-3/4 7-1/2 22-3/8 37-1/4 2-3/4 3-5/8 510


SCXG-SVX01P-EN 25

Electric Heat CoilsFigure 14. Electric Heat Coil

Table 11. Electric heat coil dimensions & weight (in)(lbs)

Unit Size A B C D Weight

20 tons 70-1/4 4-7/8 11-1/2 19 460

25 tons 70-1/4 4-1/8 11-1/2 19 460

30-35 tons 70-1/4 2-7/8 11-1/2 19 460Note: Coil box height is 8 inches.

PlenumFigure 15. Flexible horizontal discharge plenum

Table 12. Flexible horizontal discharge plenumdimensions & weights, in-lbs.

20-35 Tons A B C Weight

Low height 35 17-1/4 86-1/2 262Standard height 35 25-1/4 86-1/2 352

Waterside EconomizerFigure 16. Waterside Economizer

Table 13. Waterside economizer weights (in)(lbs)

Unit SizeWeight

2-Row 4-Row

20 - 35 tons 488 584


26 SCXG-SVX01P-EN

Airside EconomizerFigure 17. Detail “B” (top) and detail “A” (bottom)

Figure 18. Airside economizer

Table 14. Airside economizer sizes and dimensions (in.)

Size A B C D E F (1) F (2) G (1) G (2)

SCWG/SIWG 20, 25 36 65-5/8 37 74-1/4 39600 56-1/2 49-3/4 23-1/4 20-1/2

SCWG/SIWG 30, 35SCRG/SIRG 32 36 65-5/8 37 74-1/4 39600 61-3/8 62-3/4 28-1/8 20-1/2

Size H (1) H (2) J K L M Weight

SCWG/SIWG 20, 25 39573 7 20-1/2 17-1/8 12 49-3/4 273

SCWG/SIWG 30, 35SCRG/SIRG 32 38047 7 20-1/2 17-1/8 37377 62-3/4 273

Service ClearancesSee figures and table below for recommended serviceand code clearances.

Figure 19. Top View CCRC/CIRC 20, 29, 32 Ton

C B

D A

96” (2132 mm)

48” (1066 mm)

96” (2132 mm)

48” (1066 mm)

Control Panel

Figure 20. Top view of self-contained unit showingrecommended service and code clearances

See

air inlet 18” minimum

table

42” minimum

36”minimum

Control Panel


SCXG-SVX01P-EN 27

Table 15. Service and code clearance requirements

Side Distance Purpose

Front 42 in.(20-38 tons) NEC code requirement

Left18 in.36 in.77 in.

Air-cooled units onlyRefrigeration & waterside component serviceFan shaft removal

Right 36 in. Provides uniform airflow

Inlet 18 in. Provides uniform airflow

NNoottee:: When unit is ordered with horizontal supply,ensure that all applicable codes are consideredwhen installing equipment. Special attentionshould be made to overhead clearances of unit/ducting to meet code requirements.


28 SCXG-SVX01P-EN

Installation - MechanicalUnit Handling

WWAARRNNIINNGGIImmpprrooppeerr UUnniitt LLiifftt!!FFaaiilluurree ttoo pprrooppeerrllyy lliifftt uunniitt iinn aa LLEEVVEELL ppoossiittiioonnccoouulldd rreessuulltt iinn uunniitt ddrrooppppiinngg aanndd ppoossssiibbllyyccrruusshhiinngg ooppeerraattoorr//tteecchhnniicciiaann wwhhiicchh ccoouulldd rreessuulltt iinnddeeaatthh oorr sseerriioouuss iinnjjuurryy,, aanndd eeqquuiippmmeenntt oorrpprrooppeerrttyy--oonnllyy ddaammaaggee..TTeesstt lliifftt uunniitt aapppprrooxxiimmaatteellyy 2244 iinncchheess ((6611 ccmm)) ttoovveerriiffyy pprrooppeerr cceenntteerr ooff ggrraavviittyy lliifftt ppooiinntt.. TToo aavvooiiddddrrooppppiinngg ooff uunniitt,, rreeppoossiittiioonn lliiffttiinngg ppooiinntt iiff uunniitt iissnnoott lleevveell..

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Before lifting the unit or modular component,determine the approximate center of gravity for liftingsafety. See Figure 21, p. 28 for assembled modularunits and Figure 22, p. 29 for split-apart units. Thecenter of gravity may vary slightly within the gravityblock depending on unit options.

Always test-lift the unit to determine the exact unitbalance and stability before hoisting it to theinstallation location. See Figure 23, p. 29 and Figure24, p. 29 for typical rigging procedures and properrigging equipment usage.

Figure 21. Assembled unit gravity block location

Table 16. Gravity block dimensions

Model A B C D

SCWG 36 14 38 12

SCRG 36 16 40 12

SCXG-SVX01P-EN 29

Figure 22. Split-apart unit gravity block location

Figure 23. Split-apart modular unit proper rigging (L) and fan section (R)

Figure 24. Assembled modular unit proper rigging

IInnssttaallllaattiioonn -- MMeecchhaanniiccaall

30 SCXG-SVX01P-EN

Skid RemovalThe unit ships on skids to provide forklift locationsfrom the front or rear. The skid allows easymaneuverability of the unit during storage andtransportation. Remove the skids before placing theunit in its permanent location.

Remove the skids using a forklift or jack. Lift one end ofthe unit off of the skids. See Figure 21, p. 28 and Figure22, p. 29 for unit gravity block location. Slide the skidsout and lower the unit at the installation location.

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1. Position rigging sling under wood shipping skidand use spreader bars to avoid unit damage.

2. When using a forklift, exercise caution to preventunit damage.

3. Use the standard fork length to lift one end anddrag or pull unit while skidding the opposite end.

4. The unit center of gravity will fall within center ofgravity block at various locations depending on unitoptions.

5. Use hooks to lift fan section only. Do not hook intoopen channels to lift unit.

6. See unit nameplate for unit weight.

7. Do not stack units.

Installation PreparationBefore installing the unit, perform the followingprocedures to ensure proper unit operation.

1. Position the unit and skid assembly in its finallocation. If unit shipped split-apart, follow theprocedure in the “Split Apart Unit Assembly”section below before completing this step. Test liftthe unit to determine exact unit balance andstability before hoisting it to the installationlocation. See Figure 23, p. 29 and Figure 24, p. 29for typical rigging procedures, including cautionsand proper uses of such equipment as fork lifts,spreader bars, and hooks.

2. Test lift the unit to determine exact unit balance andstability before hoisting it to the installationlocation. See the “Unit Handling Procedures”

section for proper rigging procedures and cautions.

3. Remove the skids from under the unit. See “SkidRemoval” in the previous section.

4. Remove the protective shipping covers from theunit.

5. Verify isolators are properly tightened foroperation.

NNootteess::

• Unit height and connection locations willchange if external vibration isolators areused. The unit may be raised anadditional 5-7/8 inches with spring-typeisolators.

• Unit height and connection locations willchange if the unit is constructed to besplit-a-part in the field. See unitsubmittal drawings for connectionlocations.

6. Tighten compressor isolator mounting bolts.Torque to 18 ft/lbs. (± 2 ft/Lbs.)

7. Electrical supply power must meet specific balanceand voltage requirements.

8. Water-cooled units only (model SCWG):Theinstaller must furnish and install a condenser mainand standby water pump, cooling tower, pressuregauges and all components for the watersidepiping.

9. Air-cooled units only (model SCRG):These unitsrequire field-installation of a remote air-cooledcondenser and refrigerant piping.

Split Apart Unit Assembly1. Ensure the tagging information on the fan section

nameplate matches that on the compressornameplate.

2. Remove the connector brackets holding the sheetmetal shipping cover on compressor section. Retainbrackets and screws.

3. Remove shipping cover from the compressorsection and verify the ship-with package contains:

a. suction and liquid line couplings

b. insulation

c. sheet metal screws

4. Lift fan section onto the compressor section usingthe rigging method in .

5. Remove skid from the fan section, placing the fansection onto the compressor section. Reference .

6. Install the connection brackets with the sheet metalscrews (referenced in step 2) on all sides of the unit.Reference Detail “A” in .

7. Remove the unit panels labeled RU and RL in . Toremove panels, first remove the four shippingscrews located in the corner of each panel. Next,


SCXG-SVX01P-EN 31

turn the remaining 1/4 turn fasteners to the unlatchposition. The panel is supported by a “lip” channel.So, lift the panel up and off the unit to remove it.See Detail “A” in .

8. Connect the drain hose to the drain pan outletfitting and secure it with the drain hose clampprovided.

9. See “Refrigerant System,” p. 39 for pipingprocedures.

10. Remove panel FLR and open the bottom controlpanel door, FLL. Pull the fan motor leads (coiled inthe fan section) through the knockout in the bottomof the fan section to the control panel. Ensure thatthe bushing is installed in the hole to prevent thewires from chafing. Refer to the unit wiringdiagrams to connect the fan motor leads properlyand ensure correct phase sequencing.

IInntteelllliiPPaakk UUnniittss ((UUCCMM)) OOnnllyy

11. Remove panels FML, FMM, and FMR.

12. Pull the circular plug connector (CPC) from thecompressor section through the knockouts into thefan section. Install the bushings (provided on thewiring harnesses) in the knockouts.

13. Using the CPC wiring diagram, connect the maleCPC to the female CPC in the top control panel.

14. If the unit has the mixed air temperature option,route the capillary tube on back of the filter rack.

UUnniittss wwiitthh TThheerrmmoossttaatt OOnnllyy

15. Remove panel FMR. See Note 1 on Figure 25, p. 31.

16. Pull frost protection wires from the bottom controlpanel through knockouts in bottom of fan section.Route wires to the appropriate frost protectionswitches on the evaporator coil. Reference the unitwiring diagrams to connect frost protection wiringconnectors.

AAiirr--CCoooolleedd UUnniittss OOnnllyy

17. Route the refrigerant circuit wires for circuits 1 and2 from the bottom control panel through theknockouts to the solenoid valves. The solenoidvalves are located in the liquid refrigerant lines onthe right-hand side of the unit. Refer to the unitwiring diagrams to make splice connections.

Figure 25. Modular unit panel description andinternal connections

Figure 26. How to assemble the modular unit

Unit Vibration Isolator OptionIf your job requires external vibration isolation, twooptions are available: Iso-pads or spring-type isolators.Iso-pads should be placed under the unit at locationsindicated on the factory-provided isolator sheet.

Set the spring-type isolators () in position after the unitis removed from skids before making electrical, piping,or duct connections. All units require a minimum offour isolators per unit. But some may require sixisolators, depending upon unit options.

NNoottee:: Trane strongly recommends you consult avibration specialist before double-isolating theunit. Double isolation is not recommended.

If you decide to externally isolate the unit, use spring-flex, type CP isolators. The spring number is marked onthe outer housing. See .

Unit Isolator Installation ProcedureUse the following procedure to install isolators:

1. Position the isolators under the unit base referringto the isolator placement sheet that ships with theunit isolators. Lift one end of the unit at a time toposition the isolators. Fasten the isolators to thefloor using anchor bolts.

2. Level the unit by adjusting the isolator heights. Unitweight may cause the upper housing of the springisolators to rest on the lower housing. Maintain


32 SCXG-SVX01P-EN

clearances between 1/4 and 1/2". To increase theclearance, lift the unit off the isolator and turn theleveling bolt counterclockwise. Verify that the unitis level and the housing clearances are correct. Themaximum allowable difference between isolatorheights is 1/4". Shim as required under theisolators.

NNoottee:: The compressors and fan assembly are internallyisolated on most units. Due to this, the additionof external isolation devices (spring mountingisolators) is at the discretion of the building orHVAC system designer.

Figure 27. Optional spring isolator dimensional data

Duct ConnectionsWWAARRNNIINNGG

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Return air enters the rear of the unit and conditionedsupply air discharges through the top. Attach supply airductwork directly to the unit’s top panel, around the fandischarge opening. A duct collar is not provided.

NNoottee:: Units equipped with flexible horizontal dischargeplenum option may include a duct collar whenholes are factory cut. If discharge openings arefield-cut, refer to the following “Installation —Plenum” section.

Install all air ducts according to the National FireProtection Association standards for the “Installation ofAir Conditioning and Ventilation Systems other thanResidence Type (NFPA 90A) and Residence Type WarmAir Heating and Air Conditioning Systems (NFPA 90B).

Make duct connections to the unit with a flexiblematerial such as heavy canvas. If a fire hazard exists,Trane recommends using Flexweave 1000, type FW30or equivalent canvas. Use three inches for return ductand three inches for discharge duct. Keep materialloose to absorb fan vibration.

• If using return ductwork to the unit, secure it withthree inches of flexible duct connector.

• Extend discharge duct upward without change insize or direction for at least three fan diameters.

• Use 3" flexible duct connection on dischargeductwork.

NNoottee:: Compressors and fan assembly are internallyisolated. External isolation devices (springmounting isolators) are at discretion of avibration specialist consulted by building orHVAC system designer.

Run the ductwork straight from the opening for aminimum of three fan diameters. See Figure 28, p. 33.Extend remaining ductwork as far as possible withoutchanging size or direction. Do not make abrupt turns ortransitions near the unit due to increased noise andexcessive static losses. Use elbows with splitters orturning vanes to minimize static losses.


SCXG-SVX01P-EN 33

Poorly constructed turning vanes may cause airflowgenerated noise. Align the fan outlet properly with theductwork to decrease noise levels in the duct and toincrease fan performance. To complete trunk ductworkto the VAV terminal units, refer to the VAV boxmanuals for specific requirements. Check total externalstatic pressures against fan characteristics to be surethe required airflow is available throughout theductwork.

To achieve maximum acoustical performance,minimize the duct static pressure setpoint.

Figure 28. Duct connection recommendations

3 Fan Diameters

DuctDischarge

3-inch

DuctFlexible

AirReturn

Installing the PlenumBefore installing plenum, attach insulation strip thatships with plenum. See Figure 29, p. 33 for properinsulation location. Align plenum front with controlpanel side of unit. Using strips and screws provided,secure plenum to unit. Treat field-cut holes to preventfiberglass from entering the air stream.

NNoottee:: Plenum insulation must be applied properly toprevent air bypass around the plenum. SeeFigure 29, p. 33.

Figure 29. Correct plenum insulation placement

Plenum Bottom View

Dashed line indicates correct insulation placement.

Installing the Airside EconomizerUUnniitt HHaannddlliinngg

1. Hoist the damper cabinet to the installation locationwith straps positioned under the skid as shown inFigure 30, p. 34. Use spreader bars to prevent unitdamage during lifting.

2. With the damper cabinet at its final location (nearthe unit), remove the screws securing it to the skidfrom the side flanges. Retain these screws for lateruse.

UUnniitt PPrreeppaarraattiioonn

3. Open the access door and remove the dampercabinet’s support legs and its hanging bracket. Thesupport legs are secured to the skid, and thehanging bracket is secured with wire ties to aninside flange near the cabinet’s base. Remove theC-channel collar and install it on the unit, if notalready installed.

4. Remove the roll of 1/8" thick gasket from thedamper cabinet’s W-supports, and apply it to the C-channel collar mounted on the rear of the unit. Thisgasket will provide a seal between the dampercabinet and the unit.

5. Attach the legs (with screws provided) to the legbrackets located on the damper’s base.

6. Attach a field-provided clevis of suitable strength ( >1/2"), to each of the corner lifting brackets throughthe 7/8" diameter holes.

7. Attach to the clevises a means of lifting the dampercabinet from its skid.

UUnniitt IInnssttaallllaattiioonn

8. Slowly raise the damper cabinet from its skid.

9. Attach the hanging bracket across the front of thedamper cabinet. Position it with its short flangepointing to four o’clock, and secure it with screwsprovided. See Figure 30, p. 34.

10. Lift the damper cabinet and position it such that thehanging bracket is positioned over the unit’s C-channel collar.

11. Lower the damper cabinet until the holes in its sideflanges are aligned with the holes in the C-channelcollar. Install screws removed in step 3 through thedamper cabinet’s side flanges and into the C-channel’s corresponding holes.

12. Attach ductwork to the top and back dampersaccording to local codes.

FFiieelldd WWiirriinngg CCoonnnneeccttiioonnss


34 SCXG-SVX01P-EN


13. Open the damper cabinet’s door and connect theffaaccttoorryy--pprroovviiddeedd pplluugg from the actuator to theffaaccttoorryy--pprroovviiddeedd pplluugg in the unit’s filter section.

14. CCaabbiinneettss wwiitthh TTRRAAQQ ddaammppeerrss oonnllyy:: Unroll tworolls of pneumatic tubing located inside dampercabinet. Route tubes through cabinet’s front upperpanel (0.25 dia. holes provided). Connect to twopneumatic tubes protruding from customerelectrical connection panel on unit. Be sure toconnect black to black, white stripe to white stripe).

15. CCaabbiinneettss wwiitthh TTRRAAQQ ddaammppeerrss oonnllyy:: Locate the“bullet” sensor and rolled up wiring in the unit’sfilter section. Route it into the damper cabinet andinsert the sensor into the sensor mounting clipattached to underside of one of the Traq dampers.

Figure 30. Proper lifting of the airside economizer(top) and airside economizer option (bottom)

SpreaderBar

StrapLifting Cable with

spreader bar

C-Channel

Hanging Bracket

Water PipingCondenser Connections

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Condenser water piping knockouts are in the lower leftend panel. If necessary, remove insulation to gainaccess. All field-installed piping must conform toapplicable local, state, and federal codes. To completecondenser water connections follow the procedurebelow.

NNoottee:: Four (4) condenser waterline drain plugs ship ina bag in the left end of the unit. The installermust field install these four plugs using pipethread sealer. An additional plug is provided forunits with a waterside economizer.

1. Install the vent plugs in the economizer coil headersand condenser manifolds. See These plugs ship in abag with the condenser drain plugs.

2. Attach the water supply line to the inlet connection,and the return line to the outlet connection.Entering and leaving water connections for allcondensers are factory manifolded and require onlysingle connections for entering and leaving water. Ifthe unit has a waterside economizer and/or controlvalves, the factory pipes between thesecomponents.

3. If using a cooling tower, refer to for a typical pipingcircuit from the unit.

4. Ensure the water pressure to the unit does notexceed 400 psig.

NNoottee:: To prevent water pump damage, design systempiping to provide relief when using energysaving waterside economizer valves.

Condensate Drain ConnectionsThe condensate drain is internally trapped. Condensatedrain connections are on the right side of the unit.Connect condensate drain piping to the 1-1/4” NPTfemale fitting, using at least 7/8" OD copper or 3/4" ODiron pipe. Pitch the condensate line downward aminimum of 1/2" for each 10' of horizontal run, awayfrom the unit. Be sure to install the condensate drain“P” trap drain plug. Before starting the unit, fill the trapwith water to prevent negative pressure in the fansection from impeding condensate flow.To facilitatedrain pipe cleaning, install plugged tees in place of 90°elbows.


SCXG-SVX01P-EN 35

General Waterside Recommendationsfor Cooling TowersCooling tower control affects the unit cycle rates.Condenser water temperature swings from 10-15°Fmay cause excessive compressor, water valve, and unitcycling. Be sure to set the tower controls to minimizecompressor/unit cycling.

Table 17. Water connection sizes

Unit Size Direct Condenser Factory Piped

SCWG 20-35 1-1/2 NPT 2-1/2 NPT

Figure 31. Direct condenser connections

Waterside Piping ArrangementsInstall a condenser water pump between the coolingtower (either open or closed) and the self-containedunit. Lay out the remainder of the system condenserpiping in reverse returns. This helps balance thesystem by equalizing the length of supply and returnpipes. Multi-story buildings may use a direct returnsystem with balancing valves at each floor.

Install the supply riser and its return in close proximity.Furnish both with permanent thermometers to checkthe waterside balance during startup and routinemaintenance checks.

Also, include strainers at each pump inlet and unit.Install drain valves at the riser’s base to allow drainagepoints for system flushing during startup and routinemaintenance. For condenser draining and headerremoval, include a shutoff/balancing valve on theentering and leaving waterside pipes, drain tees, andunions of each unit.

NNoottee:: Unit does not have floor drains.

Figure 32. Condenser water piping components forcooling tower system

Water Temperature RequirementsDo not allow the entering water temperature to gobelow 54°F (12.2°C) on units with constant water flow(basic piping).This will cause the compressors to shutdown and the mechanical cooling function will lockout.However, the economizer (if enabled) will continue tofunction. The compressors will reset when the enteringwater temperature reaches 58°F (15°C).

Units with variable water flow (intermediate piping)have a modulating condensing pressure control valvethat allows compressor operation down to enteringwater temperatures of 35°F (2°C).

For more information on constant and variable waterflow, see the Sequence of Operation section of thismanual.

NNoottee:: Units with a waterside economizer can be setfrom the human interface panel for variable orconstant water flow.

Installing Waterside Economizer1. Loosen and pull all end devices that go through the

bushing on the filter rack (upper right corner ofrack).

2. Remove the filter rack from the back of the unit byremoving the 1/4” hex head screws from the topand bottom of the filter rack assembly. The filterrack assembly will hang on the unit when thescrews are removed. Remove the filter rack bylifting it up off the unit.

3. Remove the economizer from the crate and positionit behind the unit with the headers on the left side,when facing the back of the unit. Remove the plasticenvelope that is taped to the economizer boxassembly. This envelope contains the gasket thatmust be installed onto the vertical side flanges ofthe box.

4. Install the pressure sensitive gasket to the unit sideof the vertical flange on the economizer box.

5. Hang the economizer on the unit as shown in Figure


36 SCXG-SVX01P-EN

33, p. 36. Lift the economizer by using the holesprovided in the top panel of the economizer.

6. Align economizer holes with the holes in the unitchannel. Install screws in the top (6x) and bottom(6x) of the economizer.

7. Remove the rear middle panel of the unit andunbraze the two copper pipes in the 2-5/8” waterpipe. Do not remove the pipe outlet block-off panel.

8. Remove the economizer tubing assemblies fromthe shipping box. Check ship-separate parts againstthose shown in all figures within this section. Facethe front of the unit to see which side the water pipeexits to determine if the unit has either right or left-hand piping.

9. Assemble tubing as shown in Figure 34, p. 36 orFigure 37, p. 37. Tack all tubes in place beforebrazing to ensure proper fit-up. For right-handpiped units, install the ball valve actuator assemblyand actuator as shown in Figure 35, p. 36. Refer tothe unit wiring diagram for wiring connectionpoints.

10. Install the pipe insulation on all pipe line to preventsweating

11. Install the rear panels.

12. Re-install the filter rack on the back of theeconomizer coil box and affix with screws provided.

Figure 33. Installing the waterside economizer

Waterside Economizer with Left-handFactory Piping ComponentsFigure 34. Detail view of ship-separate tubingassemblies for waterside economizer left-hand piping

Figure 35. Waterside economizer with left-handfactory piping tubing assembly


SCXG-SVX01P-EN 37

Table 18. Waterside economizer ship-separate partslist - left-hand factory piping

Piping Item Part # Qty. Description

Left-Hand 4001 2 Tube; 2-5/8" x 9"

X17110026250 5 Elbow; 2-5/8" x 2-5/8"

4003 1 Tube; 2-5/8" x 26-1/8"

4740 1 Tube; 2-5/8" x 33-1/2"

4009 1 *Tube; 2-5/8" x 14-7/8"

X21040098390 10 ft. *Gasket

X21080406110 1 *Insulation; 2-5/8"Rubatex

X16120203570 1 Plug; 1-1/2" Brass

X17150027060 1 Bushing; 2-1/2" ftg. x 1-1/2"

X17170031210 1 Tee; 2-5/8" x 2-1/8" x 2-5/8"

4738 1 *Tube; 2-5/8" x 19-3/4"

4007 1 Tube; 2-5/8" x 14 1/2"

X45000032020 1 roll Tape, 1.5' wide

4006 1 Tube; 2-5/8" x 19-15/16"

Table 19. Waterside economizer part descriptions—left-hand piping

Item Part Description

A Assembly #1

B Assembly #2

C Assembly #3

D Assembly #4

E Tube; 2-5/8" x 16-7/8"

F Tube; 2-5/8" x 22-5/8"

Waterside Economizer with Right-handFactory Piping ComponentsFigure 36. Waterside economizer with right-handfactory piping tubing assembly

Figure 37. Detail view of ship-separate tubingassemblies for waterside economizer right-handpiping


38 SCXG-SVX01P-EN

Table 20. Waterside economizer ship-separate partslist—right-hand factory piping

Piping Item Part # Qty Description

Right-Hand 4001 1 Tube; 2-5/8" x 9"

4607 1 Tube; 2-5/8" x 17"

X17110026250 5 Elbow; 2-5/8" x 2-5/8"

4605 2 Tube; 2-5/8" x 9-1/2"

X15330177010 1 Water Valve

4008 1 *Tube; 2-5/8" x 20-1/4"

X17170031210 1 Tee; 2-5/8" x 2-1/8" x 2-5/8"

X16120203570 1 Brass Plug, 1-1/2"

X17150027060 1 Bushing; 2-1/8" ftg. x 1-1/2"

4007 1 Tube; 2-5/8" x 14-1/2"

4031 1 Tube; 2-5/8" x 62

4603 1 *Tube; 2-5/8" x 11-3/4"

4006 1 Tube; 2-5/8" x 19-1/4"

X13610256010 1 *Actuator with wires

X19110028040 2*90 Degree Conduit

Fitting

X19110028040 3ft. *1/2" Conduit

X210804060110 14ft.

*Rubatex Insulation, 2-5/8"

X450000320201r-oll

Tape, 1.5' wide

X21040098390 10ft. *Gasket

Table 21. Waterside economizer part descriptions—right-hand piping

Item Part Description

A Assembly #1

B Assembly #2

C Assembly #3

D Assembly #4

E Tube; 2-5/8" x 11-3/4"

F Tube; 2-5/8" x 20-1/4"

G Actuator Assembly

Installating the Hydronic Coil

WWAARRNNIINNGGUUnniitt SSttrruuccttuurraall IInntteeggrriittyy!!FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonnss bbeellooww ccoouulldd rreessuulltt iinnddeeaatthh oorr sseerriioouuss iinnjjuurryy..UUnniitt ppaanneellss pprroovviiddee ssttrruuccttuurraall iinntteeggrriittyy.. DDoo nnoottrreemmoovvee mmoorree tthhaann ttwwoo nnoonn--aaddjjaacceenntt ppaanneellss aatt oonneettiimmee aass tthhiiss ccoouulldd ccaauussee tthhee pplleennuumm ffrraammee ttooccoollllaappssee..

These instructions are for steam and hot water coilinstallation. Hydronic coil assembly has a full coil,piping, a modulating temperature control valve, and adisc temperature limit device located in unit near fanon motor frame. Hydronic coils are available witheither right or left-hand pipe connections. Pipingconnections are identical to unit piping. For example,for right-hand unit piping, hydronic coil will have right-hand connections. The hydronic coil assembly hastemperature controls to keep the internal cabinettemperature below 105°F to prevent motor and bearingdamage.

1. Remove filter rack from back of unit. Remove the 1/4” inch hex head screws from the top and bottomof the filter rack assembly. The filter rack assemblywill hang on the unit when the screws are removed.The filter rack can now be removed by lifting up onthe filter rack.

2. Remove the hydronic coil from crate and position itbehind unit with open side facing unit evaporatorcoil inlet. Remove the plastic envelope taped to coilbox assembly. This envelope contains themounting screws needed to attach the coil box tothe unit and the gasket required on the vertical sideflanges of the box.

3. Install the pressure sensitive gasket to the unit sideof the vertical flange on the coil box in two places.

4. Install 2" x 1/2” standard thread eyebolts into coillift plates to raise coil to height necessary to attachit to the unit. Top panel includes a “J” hook to allowhanging, similar to filter rack. Align holes so coilhangs on unit. If unit has dirty filter option, connectstatic pressure tube to unit before bolting coil inplace. Locate static pressure tubing on unitevaporator coil and route through the knockout inthe top corner of the coil box.

5. Align the hydronic coil with the holes in the unitchannel or waterside economizer option. Move thecoil box up against the unit and install using sixmounting screws in the top and six in the bottom ofthe coil box.

6. Remove the valve and pipe cover on the coil box.Connect the wires that are coiled in the coil box,referring to the wiring diagram installed on the unitcontrol panel door. Route wires into the unitthrough knockouts in the top of the box.


SCXG-SVX01P-EN 39

7. Reinstall the filter rack on the back of the heatingcoil rack. If the unit has the waterside economizeroption, the filter rack will require additional supportlegs.

Refrigerant SystemTrane Water Cooled Self-Contained units are availablein complete system or a “Split Apart” configuration.Complete systems are factory charged with R-410Arefrigerant. Split apart modules have a nitrogenholding charge and require field connection andcharging.

Trane Air Cooled Commercial Self-Contained andCondenser units ship with a dry nitrogen holdingcharge.

Before installing refrigerant piping, verify holdingcharge is present. Momentarily depress the CSCsuction or discharge line (and condenser liquid line)access port valves.

If charge is present, continue with piping installation.

If no nitrogen escapes the access valve, leak test theunit refrigerant system to determine the leak source,and repair. See Maintenance section, “Refrigerant LeakTest Procedure,” p. 97. After finding leak, remove testpressure and repair leak using proper brazingprocedures. See Maintenance section, “BrazingProcedures,” p. 98. Retest unit(s) to ensure all leaks arerepaired. Continue with piping installation.

Interconnecting PipingRefrigerant piping must be properly sized and applied.These two factors have a significant effect on bothsystem performance and reliability.

SSpplliitt AAppaarrtt UUnniittss OOnnllyy:: Join liquid and suction lineswith pipe sections provided. Use proper brazingprocedures.

Using Table 22, p. 40, select proper liquid anddischarge line size. Unit connection sizes are alsoshown. Install interconnecting piping using properinstallation and brazing procedures.

Work on only one circuit at a time to minimize systemexposure to potentially harmful moisture in the air.

Before installing piping verify compressor oil levels arenear top of sight glass or above.

NNoottee:: CSC units (and replacement compressors) shipfully charged with POE oil from the factory.Scroll compressors use POE oil (OIL00079, quartcontainer or OIL00080, gallon container), DONOT substitute.

Capped discharge and liquid line connections arelocated near bottom, left side of the indoor unit. CCRC/CIRC connections are located in the unit front, at top.

Remove caps with a tube cutter to minimize risk ofgetting chips inside piping.

NNoottee:: When facing the control panel side of the unit.Circuit #2 is always on the left and Circuit #1 isalways on the right.

Cleanliness is extremely important during systeminstallation to minimize residual contaminants, such asoxidization and scale.

Attach vacuum pump and begin evacuation as soon aspiping installation is complete. This starts systemdehydration and helps prevent POE compressor oilcontamination. This will also indicate large leaks ifvacuum does not hold (below 400 microns and hold for2 hours). Complete LeakTest and Evacuation (forprocedures, see “Refrigerant Leak Test Procedure,” p.97 and “System Evacuation Procedures,” p. 98 inMaintenance section) before starting “PreliminaryRefrigerant Charging,” p. 40.

NNootteess::

• Installation of a field supplied discharge lineaccess port near indoor units with optionaldischarge line ball valve will make high sidepressure measurements easier during leaktest.

• UseType “L” refrigerant grade coppertubing only.

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40 SCXG-SVX01P-EN

Table 22. Refrigerant piping sizes

Air Cooled Modular Connection Size (in)

SXRG Size

Circuit 1 Circuit 2

Liquid Discharge Liquid Discharge

32 5/8 7/8 5/8 7/8

Remote Condenser Connection Size (in)

Circuit 1 Circuit 2

CXRC Size Liquid Discharge Liquid Discharge

20, 29, 32 5/8 7/8 5/8 7/8

Interconnecting Tube Size (in)

Circuit 1 Circuit 2

SXRG/CXRC Size Liquid Discharge Liquid Discharge

32/32 5/8 1 1/8 5/8 1 1/8

Preliminary Refrigerant Charging

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WWAARRNNIINNGGHHaazzaarrddoouuss PPrreessssuurreess!!FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonnss bbeellooww ccoouulldd rreessuulltt iinnaa vviioolleenntt eexxpplloossiioonn,, wwhhiicchh ccoouulldd rreessuulltt iinn ddeeaatthh oorrsseerriioouuss iinnjjuurryy..IIff aa hheeaatt ssoouurrccee iiss rreeqquuiirreedd ttoo rraaiissee tthhee ttaannkkpprreessssuurree dduurriinngg rreemmoovvaall ooff rreeffrriiggeerraanntt ffrroommccyylliinnddeerrss,, uussee oonnllyy wwaarrmm wwaatteerr oorr hheeaatt bbllaannkkeettss ttoorraaiissee tthhee ttaannkk tteemmppeerraattuurree.. DDoo nnoott eexxcceeeedd aatteemmppeerraattuurree ooff 115500°°FF.. DDoo nnoott uunnddeerr aannyycciirrccuummssttaanncceess aappppllyy ddiirreecctt ffllaammee ttoo aannyy ppoorrttiioonn oofftthhee ccyylliinnddeerr..

CCAAUUTTIIOONNRReeffrriiggeerraanntt aatt FFrreeeezziinngg TTeemmppeerraattuurree!!DDiirreecctt ccoonnttaacctt wwiitthh lliiqquuiidd rreeffrriiggeerraanntt ccoouulldd rreessuullttiinn mmiinnoorr oorr mmooddeerraattee iinnjjuurryy..AAvvooiidd ccoonnttaacctt wwiitthh sskkiinn.. IIff wwoorrkkiinngg wwiitthh rreeffrriiggeerraannttiiss nneecceessssaarryy,, yyoouu MMUUSSTT wweeaarr aallll PPeerrssoonnaallPPrrootteeccttiivvee EEqquuiippmmeenntt ((PPPPEE)) iinncclluuddiinngg eeyyeepprrootteeccttiioonn,, ssaaffeettyy gglloovveess,, lloonngg sslleeeevveess,, aanndd ppaannttss..IInn ccaassee ooff ccoonnttaacctt,, ttrreeaatt tthhee iinnjjuurryy ssiimmiillaarr ttooffrroossttbbiittee.. SSlloowwllyy wwaarrmm tthhee aaffffeecctteedd aarreeaa wwiitthhlluukkeewwaarrmm wwaatteerr aanndd sseeeekk iimmmmeeddiiaattee mmeeddiiccaallaatttteennttiioonn..


SCXG-SVX01P-EN 41

NNOOTTIICCEECCoommpprreessssoorr DDaammaaggee!!FFaaiilluurree ttoo ffoollllooww tthheessee iinnssttrruuccttiioonnss ccoouulldd rreessuulltt iinnccoommpprreessssoorr ffaaiilluurree..IIff iitt bbeeccoommeess nneecceessssaarryy ttoo rreemmoovvee oorr rreecchhaarrggee tthheessyysstteemm wwiitthh rreeffrriiggeerraanntt,, iitt iiss iimmppoorrttaanntt tthhaatt tthheeffoolllloowwiinngg aaccttiioonnss aarree ttaakkeenn..•• TToo pprreevveenntt ccrroossss ccoonnttaammiinnaattiioonn ooff rreeffrriiggeerraannttssaanndd ooiillss,, uussee oonnllyy ddeeddiiccaatteedd RR––441100AA sseerrvviicceeeeqquuiippmmeenntt..•• DDiissccoonnnneecctt uunniitt ppoowweerr bbeeffoorree eevvaaccuuaattiioonn aannddddoo nnoott aappppllyy vvoollttaaggee ttoo ccoommpprreessssoorr wwhhiillee uunnddeerrvvaaccuuuumm..•• DDuuee ttoo pprreesseennccee ooff PPOOEE ooiill,, mmiinniimmiizzee ssyysstteemmooppeenn ttiimmee.. DDoo nnoott eexxcceeeedd 11 hhoouurr..•• WWhheenn rreecchhaarrggiinngg RR--441100AA rreeffrriiggeerraanntt,, ffoolllloowwpprroocceedduurreess oouuttlliinneedd iinn tthhee SSttaarrtt--UUpp sseeccttiioonn ooff tthhiissIIOOMM..•• AAllllooww tthhee ccrraannkkccaassee hheeaatteerr ttoo ooppeerraattee aammiinniimmuumm ooff 2244 hhoouurrss bbeeffoorree ssttaarrttiinngg tthhee uunniitt..

To charge the system:

1. Verify system leak check (including interconnectingpiping for air cooled systems) and evacuation arecomplete before adding refrigerant.

See “Refrigerant Leak Test Procedure,” p. 97 and“System Evacuation Procedures,” p. 98

2. Ensure field-supplied unit disconnect is OFF. Verifythat the unit 115 volt control circuit switch is OFFand reset relays have been unplugged, to preventinadvertent compressor starts.

3. Turn field-supplied unit disconnect ON to energizecrankcase heaters. Verify crankcase heaters areoperating.

4. Verify all service valves are open.

5. See CSC General Data for unit refrigerant charge.

6. See for additional charge required based on fieldpiping size and length. Add this to the chargeamount from Step 5 for the total charge.

NNoottee:: Step 6 not required for field piping under 25feet, or for water cooled system.

7. At the liquid line angle valve add as much R-410ALIQUID as possible up to, but not exceeding, totalcharge amount. Depending on conditions, it maynot be possible to add more than 60% of the totalcharge. This will be adequate for compressorstartup. More charge will be added aftercompressors are started. Use an accurate scale tomeasure and record preliminary amount ofrefrigerant added to each circuit.

NNoottee:: AAiirr CCoooolleedd OOnnllyy:: Add charge at thecondenser access valve or field supplieddischarge line access valve. If angle valve isused for charging, liquid line solenoid valveshould be open.

8. DO NOT add refrigerant in the suction line duringpreliminary charging to minimize refrigerant insystem low side prior to compressor start.

9. Record charge amount added.

10. If total charge is not reached see Final RefrigerantCharge in Startup.

11. Verify wiring has been returned to original.

NNoottee:: AAiirr CCoooolleedd OOnnllyy:: Verify liquid line solenoidvalve has been returned to original.

Table 23. Charge add —lbs per 10 ft of line

Piping Size (in) Liquid Line (lbs)Discharge Line

(lbs)

5/8 1.07 -

7/8 2.23 0.31

1 1/8 - 0.53

Note: Amounts listed are for 10 ft of pipe above 25'. Actualrequirements will be in direct proportion to the actual lengthof piping.


42 SCXG-SVX01P-EN

Installation - ElectricalUnit Wiring DiagramsSpecific unit wiring diagrams are provided on theinside of the control panel door. Use these diagramsfor connections or trouble analysis.

Supply Power WiringIt is the responsibility of the installer to provide powersupply wiring to the unit terminal block or the non-fused disconnect switch option. Wiring should conformto NEC and all applicable code requirements.

Bring supply wiring through the knockout in the lowerleft side of the unit control panel. Connect the threephase wires to the power terminal block or the non-fused disconnect switch in the control box terminals.Refer to specific wiring diagrams and fuse informationin the control panel.

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Voltage RangeVoltages must be within ±10% the nameplate voltage.Ensure the unit voltage is balanced by measuring at thecompressor terminals. Voltage imbalance on threephase systems can cause motor overheating andpremature failure. Maximum allowable imbalance is2.0%.

Voltage ImbalanceRead the voltage at the compressor terminals todetermine if it is balanced. Voltage imbalance on threephase systems can cause motor overheating andpremature failure. The maximum allowable imbalanceis 2.0%. Voltage imbalance is defined as 100 times thesum of the deviation of the three voltages from theaverage (without regard to sign) divided by the averagevoltage. For example, if the three measured voltagesare 221, 230, and 227, the average voltage would be:

(221 + 230 + 227) / 3 = 226 volts

The percentage of voltage imbalance is then:100 * (226 — 221) / 226 = 2.2%

Phase MonitorUnit is equipped with phase monitor in control box.The phase monitor will protect against phase loss,imbalance and reversal of line voltage. If a fault occurs,the red LED will energize. While the fault condition ispresent, the phase monitor interrupts the 115V controlcircuit. If no faults are observed, a green LED will beenergized.

Control Power

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In this example, 2.2% imbalance is not acceptable.Whenever a voltage imbalance of more than 2.0%exists, check the voltage at the unit disconnect switch.If the imbalance at the unit disconnect switch does notexceed 2.0%, faulty unit wiring is causing theimbalance. Conduct a thorough inspection of the unitelectrical wiring connections to locate the fault, andmake any repairs necessary.

Access the connection terminal block through thecontrol panel on the upper left side of the unit. Allwiring should conform to NEC and applicable localcode requirements.

Be sure all wiring connections are secure. Referencethe unit specific diagrams inside the control panel.

SCXG-SVX01P-EN 43

NNoottee:: Unit transformers IT1, IT3, IT4 and IT5 are sizedto provide power to the unit only.

Selection ProceduresRLA = rated load ampsCompressor LRA = locked rotor ampsFan motor LRA = locked rotor amps, N.E.C. Table 430 -150FLA = full load amps, N.E.C. Table 430 - 150

Voltage utilization range is ±10%

Determination of minimum circuit ampacity (MCA).

MCA = 1.25 x largest motor amps/VFD amps (FLA orRLA) + the sum of the remaining motor amps.

Determination of maximum fuse size (MFS) andmaximum circuit breaker size (MCB):

MFS and MCB = 2.25 x largest motor amps (FLA orRLA) + the sum of the remaining motor amps.

For units with the dual power option, there are twoelectrical circuits that need calculations using theprevious formulas:

• Circuit #1— fans

• Circuit #2— compressors

If the rating value determined does not equal astandard current rating of over current protectivedevice, use the next lower standard rating for themarked maximum rating.

Table 24. Number of compressors per unit

SCWG/SIWG/SCRG/SIRG 20 25 30 32, 35

10 HP 2 2 1 -

15 HP - - 1 2

Table 25. SXWG & SXRG compressor motorelectrical data

HP

200V 460V 575V

RLA LRA RLA LRA RLA LRA

10 41.4 267 18.6 142 15.8 103

15 56.9 351 25.5 197 23.1 146

Table 26. Electric heat—single stage

SCWG/SIWG

SCRG/SIRG Heat 200V 460V

Size kW Amps Amps

20 16 44.8 19.6

25 20 55.6 24.2

30 - 24 66.8 29.0

- 32 26 72.4 31.6

35 - 28 78 34.0

Note: Electric heat amperage should not be considered whendetermining minimum circuit Ampacity. The current of theunit in the heating mode will not exceed the current of theunit in the cooling mode.

Table 27. CCRC/CIRC condenser electrical data

To-ns

RatedVolt-age

#Fa-ns

FLA(ea.)

LRA(ea.) MCA MFS/

MCB

20,29,32

200 4 4.1 20.7 17.4 20

460 4 1.8 9.0 7.7 15

575 4 1.4 7.2 5.9 15

Note: All motors for CCRC/CIRC units are rated at 1 hp (.7457kW).

Table 28. Fan motor electrical data

HP Type

200V 460V 575V

FLA LRA FLA LRA FLA LRA

5OPD 15.3 109.0 6.6 48.0 5.2 40.0

TEFC 15.2 128.8 6.7 56.0 5.3 44.8

7.5OPD 23.3 199.0 9.7 84.8 7.8 61.4

TEFC 22.1 164.0 9.6 70.9 7.7 56.9

10OPD 29.5 260.0 12.6 118.0 10.1 72.3

TEFC 29.5 216.0 12.8 103.0 10.3 83.9

15OPD 43.4 271.0 18.9 118.0 15.1 95.9

TEFC 42.5 288.0 18.5 125.0 15.0 102.0

20OPD 57.0 350.0 24.5 156.0 19.6 126.0

TEFC 55.5 402.0 24.2 175.0 19.4 140.0

IInnssttaallllaattiioonn -- EElleeccttrriiccaall

44 SCXG-SVX01P-EN

Table 28. Fan motor electrical data (continued)

HP Type

200V 460V 575V

FLA LRA FLA LRA FLA LRA

25OPD 70.0 432.0 30.5 190.0 24.5 155.0

TEFC 71.0 523.0 30.5 188.0 24.5 140.0

Table 29. VFD electrical data

VFD L.I.C.

Without Bypass With Bypass

HP 200V 460V 575V 200V 460V 575V

7.5 23.8 10.6 8.8 25 11.3 9.3

10 32.2 14 11.1 31.6 14.3 11.3

15 48.3 21 16.6 47.7 21.3 15.6

20 61.9 27.6 21.4 60.9 27.3 22.3

25 78.2 34 26.3 76.5 34.3 27.3

Note: Values are at the maximum VFD input rating and not thereduced motor values.

Variable Frequency Drive Option(VFD)

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Variable frequency drive (VFD) option can only be usedwith IntelliPak units. TraneTR200 VFD and VFD with

bypass is available from 5 to 25 hp. All VFDs are pre-configured and run tested at factory. VFD is wallmounted.

Mounting RequirementsProper location of the VFD is important to achieveproper performance and normal operating life.Installation must be in an area where it will beprotected from:

• Direct sunlight, rain or moisture.

• Corrosive gases or liquids.

• Vibration, airborne dust, or metallic particles.

For effective cooling and proper maintenance, installthe VFD vertically to the ground using four mountingscrews.

To ensure sufficient air space for cooling there mmuusstt bea mmiinniimmuumm eight inch clearance above and belowVFD. A minimum 2" clearance is required on each side.Allow enough clearance to VFD cabinet door.

See Figure 38, p. 45 through Figure 45, p. 52 for VFDdimensions and weights.

Electrical Installation ProcedureRefer to the National Electric Code, section 310-16 forsizing power wires. All other control wires should betwisted shielded or twisted pair shielded, 20 - 14 AWG,with lead length not to exceed 164 feet. When usingshielded wire, the shield sheath must be connected atthe VFD only. Refer to unit schematic and connectiondiagrams for VFD wiring.

Variable Frequency Drive WithoutBypassTable 30. W/O Bypass VFD Frame Sizes

HP200VFrame

460VFrame

575VFrame

7.5 B1 A3 A3

10 B1 A3 B1

15 B1 B1 B1

20 B2 B1 B1

25 C1 B1 B1

Notes:1. See Figure 38, p. 45 through Figure 41, p. 48 for frame size

details.2. VFD wall-mounted by others


SCXG-SVX01P-EN 45

Figure 38. Frame A3: without bypass

Weight = 14 lbs (6.350 Kg)


46 SCXG-SVX01P-EN

Figure 39. Frame B1: without bypass



SCXG-SVX01P-EN 47

Figure 40. Frame B2: without bypass



48 SCXG-SVX01P-EN

Figure 41. Frame C1: without bypass


Variable Frequency Drive With BypassTable 31. With bypass VFD frame sizes

HP 200V 460V 575V

7.5 B1 A3 A3

10 B1 A3 A3

15 B2 B1 B1

20 B2 B1 B1

25 C1 B1 B1

Notes:1. See Figure 42, p. 49 through Figure 45, p. 52 for frame size

details.2. VFD wall-mounted by others.


SCXG-SVX01P-EN 49

Figure 42. Frame A3: with bypass



50 SCXG-SVX01P-EN

Figure 43. Frame B1: with bypass



SCXG-SVX01P-EN 51

Figure 44. Frame B2: with bypass

Weight = 105 lbs (47.627 Kg)


52 SCXG-SVX01P-EN

Figure 45. Frame C1: with bypass

Weight = 145 lbs (65.771 Kg)

Static Pressure TransducerInstallation (VAV units only)Supply air static pressure controls the inverter option.A static pressure head assembly ships separate incontrol panel for field installation in the supply air ductwork. Installer is responsible for providing pneumatictubing.

Transducer LocationPlace head assembly in an area of ductwork that willprovide an average and evenly distributed airflowpattern. Use the following guidelines to determine anappropriate installation location.

1. Locate static head assembly approximately 2/3 to 3/4 the way down longest duct run, in an areaapproximately 10 duct diameters downstream and2 duct diameters upstream of major interferences,turns, or changes in duct diameter.

2. When installing pneumatic tubing between headassembly and transducer in control panel, do notexceed 250ft for 1/4” OD tubing or 500ft for 3/8” ODtubing.

Installing the TransducerUse the following procedure to properly install thestatic pressure transducer:

1. Mount pressure sensing head assembly in ductwith sensing tip is in middle of the duct so that itwill provide a proper pressure measurement. SeeFigure 46, p. 53.

2. Connect the pneumatic tubing from the sensinghead to the push-on tubing connection in thecontrol panel. Use a plastic static pickup tubing. Donot exceed 250 feet for 1/4” OD tubing or 500 feetfor 3/8” OD tubing.

Transducer inside control panel picks up low side orreference pressure.


SCXG-SVX01P-EN 53

NNoottee:: If plastic tubing pulls away from a connection,trim it back before replacing it on the fitting.Stretched tubing may leak and cause faultycontrol.

Figure 46. Static pressure sensor installation

Duct

PressureSensor

Static PressureHead Assembly

Connectorfor 1/4”Tubing

Sheet Metal Screws(provided by installer) NOTE:

Pleace sensor inletperpendicular to airflow.

Installing Electric HeatElectric heat option consists of a single stage heaterand is used in IntelliPak™ units or units with a field-installed thermostat. Electric heater ships separate forfield installation and wiring. See Table 32, p. 53 forheater kW per unit size. Electric heat can be installed onunits with vertical discharge. It cannot be installed onunits with a plenum or horizontal discharge. See Figure47, p. 54 and Table 33, p. 54 for electric heatdimensional data.

Table 32. Available electric heat kW

Unit Size Heater kW

20 Tons 16

25 Tons 20

30 Tons 24

32 Tons 26

35 Tons 28



1. Remove fan discharge shipping covers, if notpreviously done.

2. Install open-cell gasket around discharge openingon heater.

3. Position electric heater so unit fan dischargeopenings line up with electric heater openings. Fora vertical discharge unit only, position electricheater as shown in Figure 47, p. 54.

4. Use hole pattern in electric heat as a template tomark and drill 3/16” diameter holes in unit.

5. Bolt electric heaters to unit with 1/4” sheet metalscrews.

NNoottee:: It is very important that electric heaters areselected based on unit voltage and tonnagebecause discharge opening sizes vary by unittonnage.

Electric Heat Coil Wiring ProcedureBefore wiring the electric heater, remove the unitwiring diagram from the unit control panel and refer tothe connection points.


54 SCXG-SVX01P-EN

Table 33. Electric heat dimensions - English - (inches)

Unit Size B1 B2 Z

20 Tons 10 3/4 15 5/8 27 3/4

25 Tons 12 1/4 15 5/8 26 3/4

Table 33. Electric heat dimensions - English - (inches)(continued)

Unit Size B1 B2 Z

30, 32, 35 Tons 14 3/4 15 5/8 23 3/4

Figure 47. Vertical discharge electric heat installation (TOP) and electric heater dimensions

Zone Sensor Options for ControlUnitsZone sensor options are available and can be orderedwith the unit or after the unit ships. They also can beordered through “Unitary Accessories (ACC)”/“UPGRooftop, Packaged Heat Pump, Split SystemAccessories (ACC)”. Contact your local Trane sales

office. Following is a full description of zone sensorsand their functions. Following is a full description ofzone sensors and their functions. See Table 41, p. 77for the zone sensor temperature vs. resistancecoefficient curve.


SCXG-SVX01P-EN 55

Standard with All Units: BAYSENS077

Zone temperature sensor only

This zone sensor module ships with all units, and canbe used with BAYSENS019, BAYSENS020, orBAYSENS021 remote sensors. When this sensor is

wired to one of these remote zone sensors, wiring mustbe 18 AWG shielded twisted pair (Belden 8760 orequivalent). Refer to the specific zone sensor for wiringdetails. It provides the following features and systemcontrol functions:

• Remote temperature sensing in the zone

• Morning warm-up sensor

• Zone sensor for ICS™ systems

• Zone temperature averaging

When used as a remote sensor for standard zonesensor, the thermistor sensor must be disabled.

(Possible Schematic Designation(s): 5U23, 5U26, 5U30,and 5RT5.)

CV Unit Zone Sensor Options

BAYSENS108Dual setpoint, manual/automatic changeover sensor

BAYSENS110Dual setpoint, manual/automatic changeover sensor with systemfunction

BAYSENS108 and BAYSENS110These zone sensor modules are for use with cooling/heating constant volume units. They have four systemswitch settings (heat, cool, auto, and off) and two fansettings (on and auto).The zone sensor provides eithermanual or automatic changeover control with dualsetpoint capability.

BAYSENS108 and BAYSENS110 features and systemcontrol functions include:

• System control switch to select heating mode(HEAT), cooling mode (COOL), automatic selectionof heating or cooling as required (AUTO), or to turnthe system off (OFF).

• Fan control switch to select automatic fan operationwhile actively heating or cooling (AUTO), orcontinuous fan operation (ON).

• Dual temperature setpoint levers for setting desiredtemperature. The blue lever controls cooling, andthe red lever controls heating.

• Thermometer to indicate temperature in the zone.This indicator is factory calibrated.

(Possible Schematic Designation: 5U29)

BAYSENS110 only function status indicator lightsinclude:

• SYSTEM ON glows continuously during normaloperation, or blinks if system is in test mode.

• COOL glows continuously during cooling cycles, orblinks to indicate a cooling system failure.

• HEAT glows continuously during heating cycles, orblinks to indicate a heating system failure.

• SERVICE blinks or glows to indicate a problem.These signals vary depending on the particularequipment being used.


Integrated Comfort SystemsSensors for CV and VAVApplicationsCV and VAV Unit Zone Sensor OptionsThese zone sensor options are for use with cooling/heating Integrated Comfort System (ICS) systems.


56 SCXG-SVX01P-EN

BAYSENS074Zone temperature sensor with timed override and localsetpoint adjustment

This electronic analog sensor features single setpointcapability and timed override with overridecancellation. BAYSENS074 features and system controlfunctions include:


• A timed override button to move an ICS or abuilding management system from its“unoccupied” to “occupied” mode

• Thumbwheel for local setpoint adjustment

• A cancel button to cancel the “unoccupiedoverride” command


BAYSENS073Zone temperature sensor with timed override

This electronic analog sensor features single setpointcapability and timed override with overridecancellation. It is used with a Trane® IntegratedComfort™ system.

BAYSENS073 features and system control functionsinclude:


• A timed override button to move an ICS or abuilding management system from its“unoccupied” to “occupied” mode

• Cancel button to cancel the “unoccupied override”mode


Figure 48. Zone sensor mounting hole locations for:BAYSENS077

RIGHT BACK

1-3/32 [27,43 mm]3/32 [2,00 mm]

1-3/8 [35,00 mm]

19/32 [15,00 mm]

15/64 [6,00 mm]

3-5/32 [80,00 mm]

1-1/32 [26,16 mm]

5/32 [3,81 mm] 4X

Zone Sensor InstallationWWAARRNNIINNGG



NNoottee:: For additional information regarding the safedischarge of capacitors, see PROD-SVB06


SCXG-SVX01P-EN 57

All sensor options ship in the main control panel andare field installed. Programmable option installationprocedures.

Mounting LocationMount the sensor on the wall in an area with good aircirculation at an average temperature. Avoid mountingspace temperature sensor is areas subject to thefollowing conditions:

• Drafts or “dead” spots behind doors or in corners

• Hot or cold air from ducts

• Radiant heat from the sun or appliances

• Concealed pipes and chimneys

• Unheated or non-cooled surfaces behind thesensor, such as outside walls

• Airflows from adjacent zones or other units

To mount the sensors, remove the dust cover andmount the base on a flat surface or 2" x 4" junction box.Sensors ship with mounting screws.

Mounting the SubbaseRemove the zone sensor cover from subbase, andmount subbase on the wall or on a 2 x 4 junction box.Route wires through the wire access hole in thesubbase. See Figure 49, p. 57. Seal the hole in the wallbehind the subbase.

NNoottee:: Guidelines for wire sizes and lengths are shownin Table 34, p. 57. The total resistance of theselow voltage wires must not exceed 2.5 ohms perconductor. Any resistance greater than 2.5 ohmsmay cause the control to malfunction due toexcessive voltage drop.

NNoottee:: Do not run low-voltage control wiring in sameconduit with high-voltage power wiring.

Wiring1. Run wires between the unit control panel and the

zone sensor subbase. To determine the number ofwires required, refer to the unit wiring diagrams.

2. Connect the wiring to the appropriate terminals atthe unit control panel and at the zone sensorsubbase. In general, zone sensor connections to theunit use the convention of connecting zone sensorterminals to like numbered unit terminals (1 to 1, 2to 2, etc.).The connection detail is shown on the unitwiring diagrams, which are located in the unitcontrol panel.

3. Replace the zone sensor cover back on the subbaseand snap securely into place.

Standard Remote Sensor (BAYSENS077)When using the remote sensor, BAYSENS077, mount itin the space that is to be controlled. Wire according tothe interconnecting wiring diagrams on the unit.

Table 34. Zone sensor maximum lengths and wiresize

Distance from Unit toController

RecommendedWiringSize

0-150 feet 22 gauge

151-240 feet 20 gauge




Figure 49. Typical zone sensor installation

Junc-

tion

Mounting to Junction Box

Mounting Directly to the Wall

Time Clock OptionGrasslin Time Clock Option

The time clock option has a programmable timer that isfactory wired to the unoccupied input to provide on/offcontrol. The time clock will not allow the unit to passthrough the night setback/morning warm-up mode,except on units with optional night heat/morningwarm-up, or programmable night setback.


58 SCXG-SVX01P-EN

The time clock, a “Digi 20” by Grasslin, is inside thecontrol panel, but accessible with the control paneldoor closed. This same type timer is also used forprogrammable night setback/morning warm up.Programming instructions for the “Digi 20” timer are inthe “Programming” section.

Installing the Time Clock1. Ensure operating temperature is between 4°F and

131°F.

2. Locate the time clock at least 5 feet away from anylarge electrical contact or machinery to avoidpossible electrical interference problems.

3. Provide a separate independent circuit for the timeclock power supply.

4. Since all electronic instruments are sensitive tovoltage spikes, pay close attention to the following:

a. If possible, supply power to the electronic timeclock from a phase different than the onesupplying power to the load.

b. Provide a suitable Varistor or RC network acrossthe INDUCTIVE LOADS supply terminals toreduce voltage spikes.

c. Place a diode across the DC OPERATEDINDUCTOR terminals to eliminate back EMF.

d. HIGHLY INDUCTIVE LOADS, especiallyfluorescent lights, may require a relay in whichcase, then Step a and Step c apply.

The time clock can be surface or flush mounted. Lift offthe front cover and loosen the two screws on oppositecorners. Pull off the base’s plug with a left to rightrolling motion.

Surface Mounting Inside Panel1. Place screws through the base’s preset holes and

screw to back of panel or wall.

2. Wire according to the instructions in the followingsection. Depending upon the specific installation,you may find it more convenient to complete wiringbefore attaching the base.

3. Place the terminal cover over the terminal block byaligning the two screws with the corner holes in thebase.

4. Push the timer firmly onto the plug in the base.

5. Tighten the two screws. A base for DIN railmounting is optional.

Wiring the Time Clock1. Wire 24, 120, or 220 VAC to input terminals. Make

sure to apply correct voltage. Using incorrectvoltage will void the warranty.

2. Connect wire to the screw terminals according tothe unit wiring diagrams. Use 12 to 22 AWG wire.

Remote Human Interface PanelInstallationHuman Interface (HI) PanelThe HI enables the user to communicate necessary unitoperating parameters and receive operating statusinformation from within the occupied space.

The HI displays top level information in the LCDwindow, unless the operator initiates other displays,for the various unit functions. It also displays menureadouts in a clear language 2 line, 40 character format.The 16-key keypad allows the operator to scrollthrough the various menus to set or modify theoperating parameters. See figure below to referencethe Human Interface (HI) panel keypad.

Figure 50. Human interface (HI) panel keypad

Remote Human Interface PanelThe remote human interface (RHI) panel is identical tothe unit mounted HI with the exception of the “unitselect” key. This key allows the operator to switch fromone unit to the next to program or view statusinformation regarding a particular unit.

The RHI functions the same as the unit mounted HIwith two exceptions. The first is the test start function.The operator can view the service parameters, but canonly initiate the service test function at the unit. TheRHI door has a locking screw to deter access by


SCXG-SVX01P-EN 59

unauthorized personnel. Additionally, the RHI cancontrol up to four different units.

Location RecommendationsThe HI microprocessor module is mounted inside amolded plastic enclosure for surface mounting. It is notweatherproof. Therefore, it is only applicable for indooruse.

Locate the RHI panel in an area that will ensure thecommunication link between the panel and the unit(s)does not exceed 5,000 feet maximum or pass betweenbuildings. See Table 36, p. 59.

The run length of the low voltage AC power wiring tothe remote HI must not exceed three ohms/conductor.Refer to Table 36, p. 59.

Table 35. Maximum communication link wiringlength

Max. Wire LengthMax. Capacitance

Between Conductors

1,000 ft up to 60 pf/ft





Note: pf/ft = picofarads/foot

Ambient Temperature and HumidityLimitsAmbient operating conditions:

• Temperature: 32 to 120°F

• Relative humidity: 10 to 90%, non-condensing

Ambient Storage Conditions

• Temperatures: -50 to 200°F

• Relative humidity: 5 to 95%, non-condensing

Table 36. Wiring recommendations for the remote HIpanel

Distance to Remote HI RecommendedWire Size

0-460 feet 18 gauge



Mounting the Remote HumanInterface (RHI) PanelThe installer must provide all mounting hardware suchas; hand tools, electrical boxes, conduit, screws, etc.Refer to Figure 51, p. 60 for the mounting hole and

knockout locations.

ProcedureRefer to Figure 51, p. 60 and follow the procedurebelow for mounting the remote HI panel on a 4" x 4"electrical junction box. Place the microprocessor in aclean dry location during the enclosure mountingprocedures to prevent damage.

1. Mount an electrical junction box in the wall so thatthe front edge of the box will be flush with thefinished wall surface.

2. Prior to mounting the panel, the microprocessormodule must be carefully removed from theenclosure. To remove the module:

a. Lay the remote panel face up on a flat surfaceand remove the locking screw from the righthand bottom end of the panel.

b. Remove the recessed hinge screw from the lefthand bottom end of the panel.

c. Unlatch the door of the enclosure as if to openit, and slide the left hand side of the doorupward away from the hinge. Lay it aside.

d. With the key pad visible, remove the two screwslocated on the right hand side of the key pad.

e. Carefully slide the key pad plate upward fromthe bottom, releasing the extruded hinge pinfrom its socket at the top.

f. Set the microprocessor aside until mounting iscomplete.

3. Remove the junction box knockout in the back ofthe enclosure.

NNoottee:: The top of the enclosure is marked “TOP.”

4. With the enclosure in the correct position; align themounting holes around the knockout in theenclosure with the screw holes in the electricalhandy box and secure with the appropriate screws.

5. Replace the microprocessor within the enclosure asfollows:

a. Verify that the terminal block jumpers areconnected properly.

b. Slide the extruded hinge pin at the top left of thekey pad plate into the hole located at the top lefthand side of the enclosure.

c. Slide the bottom of the plate into place, aligningthe two clearance holes with the screw holes onthe right. Install the screws but do not tighten.

NNoottee:: If the two screws are not installed ascalled out in the previous step, holdagainst the key pad plate while installingthe door in the next step, to prevent itfrom falling out.

d. Slide the extruded hinge pin at the top left of thedoor into the hole located under the bottom leftside of the display.


60 SCXG-SVX01P-EN

e. Install and tighten the hinge screw located at thebottom left side of the enclosure.

Wall Mounting the RHI Panel1. Prior to mounting the panel, the microprocessor

module must be removed from the enclosure.Complete Step 2 in the previous section beforeproceeding.

2. With the microprocessor removed, refer to Figure51, p. 60 for the location of the mounting holes tobe used for wall mounting.

3. Place the enclosure against the mounting surfaceand mark the mounting holes.

NNoottee:: Note: The top of the enclosure is marked with“TOP.”

4. With the enclosure in the correct position, removethe enclosure and drill the necessary holes in thesurface for the appropriate fasteners, (plasticanchors, molly bolts, screws, etc.)

5. Remove the necessary knockouts for the wire orconduit entry before mounting the panel.

6. Place the enclosure back onto the surface andsecure it with the appropriate screws.

7. Follow Step 5 in the previous section to replace themicroprocessor within the enclosure.

Figure 51. Remote HI mounting holes and knockout locations

Wiring the Remote HumanInterface



SCXG-SVX01P-EN 61

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The remote human interface requires 24 VAC + 4 voltspower source and a shielded twisted paircommunication link between the remote panel and theinterprocessor communication bridge (ICPB) module atthe self-contained unit.

Field wiring for both the low voltage power and theshielded twisted pair must meet the followingrequirements:

IImmppoorrttaanntt:: To prevent control malfunctions, do not runlow voltage wiring (30 volts or less) inconduit with higher voltage circuits.

• All wiring must be in accordance with NEC andlocal codes.

• Reference Table 36, p. 59 for recommended wiringdistance and size.

• Communication link wiring must be 18 AWGshielded twisted pair (Belden 8760, or equivalent).

• Communication link must not exceed 5,000 feetmaximum for each link. See Table 35, p. 59

• Do not run communication link between buildings.

Low Voltage (AC) Field WiringConnections1. To access the wire entry locations, open the RHI

panel door and remove the two screws on the right-hand side of the key pad.

2. Swing the keypad open, exposing both the wireentries and the back of the HI module.

3. Refer to Figure 51, p. 60 and connect one end of thethree conductor 24 volt wires to the remote panelterminal strip (+), (-), and (ground).

Interprocessor Communication BridgeModule Wiring1. Refer to the figure below and trim the outer

covering of the shielded cable back approximatelyone inch.

2. Cut the bare shield wire off even with the outercovering.

3. Strip approximately 1/2" of insulation from eachinsulated wire in order to connect them to theterminal strip at the unit.

4. Wrap tape around any exposed foil shield and/orbase shield wire.

NNoottee:: The communication link is polarity sensitive.

Figure 52. Dressing shielded twisted wire

Communication Link (Shielded TwistedPair) Wiring1. Trim the outer covering of the shielded cable back

approximately 1 inch. See the “Dressing shieldedtwisted wire” figure above. Do not cut the bareshield wire off.

2. Strip approximately 1/2–inch of insulation fromeach insulated wire to connect them to the terminalstrip at the remote panel.

3. Connect the white lead to the positive (+) terminal,the black lead to the negative (-) terminal, and thebare shield wire to the terminal at the remotehuman interface panel.

4. Close the key pad plate and install and tighten thetwo screws removed earlier.

5. Close the outer door and install the recessedlocking screw at the bottom right hand side of theenclosure to prevent accidental starting of the unitby unauthorized personnel while completing thewiring at the self-contained unit.

At the Self-Contained Unit1. Connect the opposite end of the three conductor 24-

volt wire to the appropriate terminal strip asfollows:

NNoottee:: Although the 24 volt power is not polaritysensitive, do not connect either the + (plus) or- (minus) terminals from the remote panel toground at the self-contained unit.

2. Connect the wire connected to the positive (+)terminal at the remote panel.

3. Connect the wire connected to the negative (-)terminal at the remote panel.


62 SCXG-SVX01P-EN

4. Connect the ground wire from the remote panel tothe unit control panel casing.

5. Refer to the unit wiring diagram and connect thewhite lead to the positive (+) terminal and the blacklead to the negative (-) terminal. (These terminalsare numbered. Reference to color is for clarificationto maintain polarity).

NNoottee:: To maintain polarity, do not connect the baseshield wire to ground at the self-containedunit.

Connecting to Tracer Summit


IntelliPak™ commercial self-contained (CSC) unitsoperate with Trane building automation software,Tracer Summit version 10.0.4 or later or any OS2operating system.

NNoottee:: Tape the non-insulated end of the shield onshielded wire at the unit. Any connectionbetween the shield and ground will cause amalfunction. If daisy-chained in the unit, spliceand tape the shields to prevent contact withground.

Communication WiringNNoottee:: Communication link wiring is a shielded, twisted

pair of wire and must comply with applicableelectrical codes.

An optional communication link provides a serialcommunication interface (SCI) between Tracer Summitand each commercial self-contained (CSC) unit in thesystem. The CSC system can have a maximum of 12CSC units per connection link to Tracer Summit. Use asingle 18 AWG shielded, twisted pair wire withstranded, thinned copper conductors to establish eachcommunication link between Tracer Summit and eachunit.

Programming the Time ClockOptionSetting the Time ClockUse the following instructions to set the time clock:

IImmppoorrttaanntt:: Depress the reset key before beginning toset time and program.

1. Select military (24:00 hr.) or AM/PM (12:00 hr.) timemode by depressing and holding the “h” key whilepressing “+ 1h” key to toggle between military andAM/PM. (AM appears in the display when in AM/PMmode.)

2. Press and hold down “🕒” key.

3. If setting the time when daylight savings time is ineffect, press “+ 1h” key once (+ 1h will appear indisplay).

4. Set hour with “h” key. If AM or PM does not appearin display, the unit is in military time. See noteabove to change display.

5. Set minutes with “m” key.

6. Press “Day” key repeatedly to the day of the week.(1 is Monday, 7 is Sunday)

7. Release “🕒” key, colon will begin flashing.

NNoottee:: If keys h + or m + are kept depressed for longerthan 2 seconds, a rapid advance of figures willresult.

The “Digi 20” electronic time switch is freelyprogrammable for each day of the week in one minuteincrements. For easy and quick programming, thefollowing 4 block programs are available:

• Monday through Sunday

• Monday through Saturday

• Monday through Friday

• Saturday and Sunday

Programming the Time ClockUse the following instructions to program the timeclock:

1. Press “Prog.” key. 1234567 AM —:— will appear indisplay. (Pressing “Prog.” key again, display willshow the number of free programs “Fr 20”). Pressagain to RETURN to 1st program.

2. Press “👌”key,“◉” ON symbol will appear. Pressingthe key again will toggle to OFF “❍”. Select ON orOFF for the program.

3. Press “h+” to select hour for switching time.

4. Press “m+” to select minute for switching time.

5. If the program is to occur every day of the week, (24hour time control) ignore “Day” key and press“Prog.” key to advance to program.

6. For 7 day time control, press “Day” key. 1 2 3 4 5 6


SCXG-SVX01P-EN 63

(Monday through Saturday) block of days appearsin display. Pressing “Day” key again, 1 2 3 4 5(Monday through Friday) appears in display.Repeated presses will cycle through all days of theweek and back to 1 through 7 (Monday throughSunday). Select day or block of days desired.

7. Press “Prog.” key and repeat steps 2 through 6a toenter additional programs of ON and OFF times.(Note that more than one OFF time may beprogrammed, enabling automatic control ormanual overrides.)

8. Press “🕒” key to enter run mode.

Reviewing and Changing ProgramsUse the following instructions to review and changeprograms:

1. To review a program at any time, press “Prog.” key.Programs display in the sequence they wereentered with repeated presses of “Prog.” key.

2. To change a program, select that program asoutlined in step 1. Enter the time of day and days ofweek just as in the programming steps above.Theold program is overwritten with the new selections.Press “Prog.” to store the new program.

3. To delete an individual program, select the programas in step 1 and press “h” and “m” keys until “—:—” appears in the display. Press either “Prog.” or“¹” key until“—:—” flashes.The program is deletedafter a few seconds.

Manual OverrideWhile in the “run” mode (“🕒” symbol is displayed),pressing the “👌” key will reverse the load status(switch load off if it is on, or switch it on if it is off). Ahand symbol appears in the display to indicate theoverride is active. At the next scheduled switchingtime, automatic time control resumes, eliminating theoverride.

Pressing the “👌” key a second time “◉” appears in thedisplay indicating the load is permanently on.

Pressing the “👌” key a third time “❍” appears in thedisplay indicating the load is permanently off.

Pressing the “👌” key a fourth time returns toautomatic, “👌” appears in the display.

All days shown in the respective blocks will switch on(or off) at the selected hour and minute.


64 SCXG-SVX01P-EN

Operating PrinciplesControl Sequences of OperationOccupied/Unoccupied Switching• Night setback zone sensor

• Field-supplied contact closure (hard wired binaryinput to RTM)

• Tracer Summit

• Factory-mounted time clock

Field-Supplied Occupied/UnoccupiedInput on the RTMThis input accepts a field-supplied switch or contactsclosure, such as a time clock, with a rating of 12 mA at24 VDC minimum.

Tracer Summit SystemThe Tracer Summit system can control the occupied/unoccupied status of the self-contained unit.

Factory-Mounted Time ClockA time clock can control the occupied/unoccupiedstatus of the self-contained unit.

Unoccupied Sequence ofOperationThe unoccupied mode helps conserve energy duringtimes when a building is usually unoccupied. When inunoccupied mode, the unit will control to theunoccupied setpoints (usually a lower heating setpointand higher cooling setpoint). Setpoints can beprogrammed at the HI, Tracer Summit, or the nightsetback zone sensor.

The unit enters the unoccupied mode when the RTMreceives a closed signal on the unoccupied input formore than five seconds. For units with supply airtemperature control entering unoccupied mode, thefollowing sequence will occur:

• Heating/cooling functions cease and theeconomizer option closes fully. The supply fanshuts down for proper cool-down time of the heatexchanger. However, the supply fan may remain onfor a short period of time.

• After the supply fan shuts down, the occupied/unoccupied relay energizes, and the VAV box stroketime begins. The VAV box stroke time is fieldadjustable to allow time for VAV boxes to go to thefull open airflow position.

• After the max VAV box stroke time expires, thesupply fan, economizer (if enabled), compressors,and heat are enabled to satisfy the unoccupied zonetemperature setpoints.

NNoottee:: Unoccupied economizer operation can beenabled or disabled at the HI or using TracerSummit.

Figure 53. Typical cycling morning warm-up cycle

MWUVentilationEnable

MorningWarmupTemperature

For units without volume control entering unoccupiedmode, the following sequence will occur:

• The occupied/unoccupied relay energizes and theeconomizer option fully closes.

• The fan mode is set to auto and the unit will controlto the unoccupied zone temperature setpoints.

With MWU enabled at the HI, if the zone temperature isbelow the MWU setpoint, the unit enters the MWUmode.

Morning Warm-upThis feature can be enabled at the HI, and can be usedwith factory- or field-installed heat. If MWU is notrequired disable the function in the setup menu at theHI. MWU transitions the zone from unoccupied tooccupied. It will heat until the MWU setpoint is met.The unit is then released to occupied mode. Supplyduct static pressure is maintained during thissequence. MWU can be set (at the HI) to function aseither full or cycling capacity.

Full Capacity Morning Warm-up (MWU)Full capacity morning warm-up uses full heatingcapacity to heat the zone as quickly as possible. Fullheating capacity is provided until the morning warm-up setpoint is met. At this point, the unit is released todaytime mode.

Cycling Capacity Morning Warm-up(MWU)Cycling capacity morning warm-up provides a moregradual heating to overcome “building sink” as thezone is heated. Normal zone temperature control withvarying capacity is used to raise the zone temperatureto the MWU zone temperature setpoint. This method ofwarm-up is used to overcome the “building sink”effect.

SCXG-SVX01P-EN 65

Reference Figure 53, p. 64 for a pictorial explanation ofthe cycling MWU sequence. Cycling capacity MWU willheat until MWU temperature setpoint is reached. Next,a 60-minute timer begins. If the building load reachesthe MWU ventilation setpoint, or the 60 minutes expire,whichever is first, the airside economizer will control tothe minimum position. MWU will end when the zonetemperature rises above the MWU terminate setpoint.

Timed Override Activation—ICS™This function is operational whenever the unit’s RTMmodule is used as the zone temperature sensor source,which can be set at the HI panel. When this function isinitiated by the push of the override button on the zonesensor, the unit will switch to the occupied mode. Unitoperation (occupied mode) during timed override isterminated by a signal from Tracer.

Timed Override Activation—Non-ICSThis function is active whenever the unit’s RTM moduleboard is selected as the zone temperature source,which can be set at the human interface panel. Whenthis function is initiated by the push of the overridebutton on the zone sensor, the unit will switch to theoccupied mode. Automatic cancellation of the timedoverride mode occurs after three hours of operation.

VAV Drive Max OutputThis is a single-pole, double-throw relay rated at amaximum voltage of 24 vac, two amps max. The relaycontacts of this relay switch when the unit goes fromthe occupied mode to the unoccupied mode by meansof the unoccupied binary input, night setback zonesensor, or Tracer Summit. The contacts will stayswitched during the unoccupied and morning warm-upmode. They will return to the position shown on theunit wiring diagram when the unit returns to theoccupied mode. The intent of this binary output is tosignal the VAV boxes or other terminal devices to go toa full open airflow position.

Occupied SequenceAll setpoints can be adjusted using the HI panel. Also,cooling/heating setpoints can be adjusted in the zone, ifusing an adjustable zone sensor. For a complete list ofunit setpoint default values and ranges, see theIntelliPak™ Self-Contained Programming Guide, PKG-SVP01*-EN.

Occupied Zone Temperature—CoolingThe unit transitions from unoccupied to occupied whenthe occupied/unoccupied input on the RTM is open formore than five seconds after having been closed. Thisinput can be received from Tracer Summit, the remoteNSB zone sensor, the timed override function, or a fieldsupplied contact. Dependent on unit options and the HIprogramming, the following sequence will occur:

• The unit will begin MWU and then switch to theoccupied mode after the MWU setpoint is met.

• Purge will be enabled by Tracer Summit. ThenTracer Summit will enable the occupied mode.

• The unit will switch from unoccupied to occupiedcontrol immediately.

Upon entering occupied mode, the occupied/unoccupied relay will de-energize.

Zone Temperature Control (Unit ModelNumber Digit 9 = 4 or 5)A zone sensor located directly in the space sends inputto the RTM while the CV unit is in occupied coolingmode. When the unit is in occupied cooling, the RTMcontrols the zone temperature within the coolingsetpoint deadband by modulating the economizeroption and/or staging mechanical cooling on and off asrequired.

Supply Air Temperature Control (UnitModel Number Digit 9 = 1, 2, 3, or 6)When the VAV unit is in occupied cooling, the RTMcontrols the supply air temperature to the specifiedsupply air cooling setpoint by modulating theeconomizer option and/or staging mechanical coolingon and off as required. The changeover relay contacts(field supplied) must be open on units with hydronicheat for cooling to operate.

CoolingUpon entering occupied mode, the RTM receives aninput from either the HI, RHI, Tracer Summit, or theGBAS to start the supply fan. The RTM supply fancontacts close and energize the supply fan contactor.When the supply fan starts, the fan proving switchcloses, signaling the RTM that airflow is established.The VFD will ramp the fan, and/or the airsideeconomizer dampers will open to the user-definedminimum position.

When a cooling request is sent to the RTM from thezone sensor, the RTM evaluates the system operatingconditions using the supply air and outdoortemperature input before sending the request to theMCM for mechanical cooling. If outdoor conditions(temperature and humidity) are suitable or the EWT iswithin specified setpoints, the RTM will attempt to use“free cooling” without using any compressors. TheRTM will use either the airside or waterside economizeroption. When outdoor air conditions are not suitable,only mechanical cooling will function and outside airdampers will remain at their minimum position. If theunit does not have an economizer, mechanical coolingwill operate to satisfy cooling requirements.

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66 SCXG-SVX01P-EN

Units With EconomizerIf the entering condenser water temperature (units witha WSE) or the outside air enthalpy (units with an ASE)is appropriate to use “free cooling,” the economizerwill attempt to satisfy the cooling zone temperaturesetpoint.

NNoottee:: When using an ASE with economizer enabled, O/A temperature enable can be used instead ofcomparative enthalpy if the O/A temperaturefalls below the economizer setpoint.

Then compressors will stage on as necessary tomaintain supply air temperature setpoint, which isuser-defined at the HI. Minimum on/off timing ofcompressors prevents rapid cycling.

When both airside and waterside economizers are on asingle unit, priority must be set at the HI. Theeconomizer with the highest priority attempts coolingfirst. Once it is operating at its maximum, and ifadditional cooling is necessary, the other economizerenables before mechanical cooling begins.

Cooling/Waterside EconomizerWaterside economizing enables when the unit’sentering water temperature is below the unit’s enteringmixed air temperature by 4°F plus the user adjustableeconomizer approach temperature. The approachtemperature default is 4°F.

Waterside economizing disables when the unit’sentering water temperature is not below the unit’sentering mixed air temperature by at least the watereconomizer approach temperature (default value of 4°F).The economizer acts as the first stage of cooling. Ifthe economizer is unable to maintain the zone (CVunits) or supply air (VAV units) temperature setpoint,the compressor module will bring on compressors asrequired to meet the setpoint.

Cooling/Airside EconomizerOn units with an airside economizer, a call for coolingwill modulate the fresh air dampers open. The rate ofeconomizer modulation is based on deviation of thezone temperature from setpoint; i.e., the further awayfrom setpoint, the faster the fresh air damper will open.The first stage of cooling will start after the economizerreaches full open.

NNoottee:: The airside economizer will only function freely ifambient conditions are below the enthalpycontrol settings or below the return air enthalpyif unit has comparative enthalpy installed. Ifoutside air is not suitable for “economizing,” thefresh air dampers drive to the minimum openposition. A field adjustable, factory defaultsetting at the HI panel or Tracer Summit canprovide the input to establish the minimumdamper position.

When outdoor air conditions are above the setpoint orcomparative enthalpy control setting, only mechanical

cooling will function and outside air dampers willremain at their minimum position.

Mechanical CoolingIf the zone temperature cannot be maintained withinthe setpoint deadband using the economizer option orif there is no economizer, the RTM sends a coolingrequest to the MCM. The compressor module checksthe compressor protection circuit before closing stageone. After the first functional stage starts, thecompressor module monitors the saturated refrigeranttemperature and closes the condenser fan outputcontact when the saturated refrigerant temperaturerises above the lower limit setpoint.

Air-Cooled Units OnlyThe compressor module closes the condenser fanoutput contact when the saturated refrigeranttemperature rises above the lower limit setpoint.

Water-Cooled Units OnlyThe WSM modulates the condenser coil water valvesto maintain condenser temperature, if applicable.Otherwise, it will check the entering condenser watertemperature to ensure it is greater than 54°F or if not, itwill lock out cooling.

Auto Changeover (Units with Heat Only)When the system mode is in auto, the mode willchange to cooling or heating as necessary to satisfy thezone cooling and heating setpoints. The zone coolingand heating setpoints can be as close as 2°F (1.1°C).

Occupied Zone Temperature—HeatingRelies on input from a sensor directly in the space,while a system is in occupied heating mode or anunoccupied period, to stage electric heat on and off ormodulate the hydronic heating valve as required tomaintain the zone temperature within the heatingsetpoint deadband. The supply fan will operate whenthere is a request for heat.

Electric HeatOn units with electric heat, the zone temperature canbe controlled to a heating setpoint during the occupiedmode by cycling a single stage electric heater. Aninterface can be provided for field supplied electric heat(up to three stages).The zone temperature heatingsetpoint and deadband are user defined at the HI panel.

Hydronic Heat: Hot Water or SteamOn units with hot water or steam heating, the zonetemperature can be controlled to a heating setpointduring the occupied mode. The zone temperatureheating setpoint and deadband are user defined at theHI panel or zone sensor. VAV occupied heating initiatesby closing a field-supplied switch or relay contacts


SCXG-SVX01P-EN 67

connected to the changeover input on the RTM. Supplyair static pressure is maintained.

Supply Air Setpoint Reset (VAV UnitsOnly)Supply air reset can be used to adjust the supply airtemperature setpoint on the basis of a zonetemperature or outdoor air temperature. Supply airreset adjustment is available at the HI panel for supplyair heating and supply air cooling control.

Reset Based on Outdoor AirTemperatureOutdoor air cooling reset is sometimes used inapplications where the outdoor temperature has alarge effect on building load. When the outside airtemperature is low and the building cooling load is low,the supply air setpoint can be raised, therebypreventing subcooling of critical zones. This reset canlower usage of mechanical cooling, thus savings incompressor kW, but an increase in supply fan kW mayoccur.

Outdoor air heating reset is the inverse of cooling, withthe same principles applied.

For both outdoor air cooling reset and heating reset,there are three user defined parameters that areadjustable through the human interface panel:

• Beginning reset temperature

• Ending reset temperature

• Maximum amount of temperature reset

Reset Based on zone temperatureZone reset is applied to the zone(s) in a building thattends to overcool or overheat. The supply airtemperature setpoint is adjusted based on thetemperature of the critical zone(s).This can have theeffect of improving comfort and/or lowering energyusage. The user-defined parameters are the same asfor outdoor air reset.

Supply AirTempering (Hot Water andSteam VAV Units Only)When supply air temperature falls below the supply airtemperature deadband low end, the heating valvemodulates open to maintain the minimum supply airtemperature setpoint.

Daytime Warm-up (Units with Supply AirTemperature Control Only)During occupied mode, if the zone temperature falls toa preset, user-defined zone low limit temperaturesetpoint, the unit is put into daytime warm-up. Thesystem changes over to CV heating, the VAV boxesdrive full open. However, unit airflow modulationcontrol operates to maintain duct static setpoint, andfull heating capacity is provided until the daytime

warm-up setpoint is reached. The unit is then returnedto normal occupied mode.

Supply AirTemperingSupply air tempering is available on units withoutvolume control and with hot water, steam, or electricheat or units with supply air temperature control withsteam or electric heat. When the unit is in heat modebut not actively heating, if the supply air temperaturedrops to 10°F (5.5°C) below the occupied zone heatingtemperature setpoint, electric heat will stage on or thehydronic valve will modulate to maintain a minimumsupply air temperature. The unit transitions out of heatmode if the supply air temperature rises to 10°F (5.5°C)above the occupied zone heating temperature setpoint.

ChangeoverThis mode only functions on units with supply airtemperature control with hydronic heat. When thechangeover binary input is closed the unit will controlto a discharge air heating setpoint. This setpoint isentered from the HI, and can be a higher temperaturethan the supply air cooling setpoint. This functionmaintains duct static pressure.

Thermostatic Expansion ValveNNOOTTIICCEE

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Refrigerant system reliability and performance isheavily dependent upon proper superheat. Theimportance of maintaining the proper superheatcannot be overemphasized. Accurate measurements ofsuperheat will provide the following information:

• How well the expansion valve is controlling therefrigerant flow.

• The efficiency of the evaporator coil.

• The amount of protection the compressor isreceiving against flooding.

The expected range for superheat is 14-20°F at full loadconditions. At part load, expect a properly adjustedexpansion valve to control to 8-12°F superheat.Systems operating with lower superheat could causeserious compressor damage due to refrigerantfloodback.

CompressorsUnits use two sizes of hermetic scroll compressors, 10and 15 hp, and have from two to six compressors.When viewing the front of the unit, compressors areidentified A through F from left to right. The secondcompressor from the left, or B compressor, is always


68 SCXG-SVX01P-EN

the first to come on, unless locked out for amalfunction or shut off on frost protection. See Table37, p. 69 for compressor cycling stages and and forpercent cooling capacity by stage.

R-410 compressors have belly band heaters that mustbe energized 24 hours before starting compressor.Power to the unit will energize the heaters. Heaters willbe energized during the off-cycle as long as the unithas power. Failure to perform these pre-startinstructions could result in compressor damage.

The control system logic permits compressor operationonly after the supply fan is on. If the supply fan shutsdown, compressors will not operate. Units withouthead pressure control (units with intermediate pipingpackages) will lock out mechanical cooling when theentering condenser water temperature falls below 54°F.Mechanical cooling will resume when the enteringcondenser water temperature exceeds 58°F.

Compressor CyclingCompressors cycle to maintain the operating staterequired by the temperature controls. In the event of acompressor failure, the next available compressorturns on. Refer to Table 37, p. 69 for compressorcycling by unit model and tons.

During normal conditions, compressors will not shutoff until they have been on for at least three minutesand will not turn on until they have been off for at leastthree minutes. Normal operating conditions areestablished on an individual compressor basis. When acompressor starts, its timer also starts. The compressorevaporator circuit frost protection can override the“minimum” timer and reduce the five minuteminimum required time period.

When the unit is powered up, or manually reset therewill be a three to eight minute delay before the firstcompressor may be turned on as requested by the unittemperature control algorithm.

Compressor Lead/Lag OperationCompressor lead/lag is a user-selectable feature at theHI panel and is available on all units. After each requestfor compressor operation, the lead refrigeration circuitor compressor switches, thereby causing a moreequitable or balanced run time among compressors.

When lead/lag is enabled, each time the system cycles,it will alternate between the standard compressorstaging and the lead/lag staging. Using Table 37, p. 69,a SXWF 29-ton unit will first stage compressor B thenA, then AB for

first cycle and A, then AB for the second cycle.Appropriate condenser valves (water-cooled andcondenser fans (air-cooled) will stage with appropriate

compressors to maintain saturated condensingtemperature. Enabling lead/lag may drop a coolingstage when compared to standard staging. See Table37, p. 69 for compressor staging.

Step ControlSteps of mechanical cooling are control based onsupply air or zone temperature. See Table 37, p. 69 forcompressor staging.

Capacity is based on an integrating control concept.The unit capacity matches the existing load andmaintains an average supply air temperature within thesupply air setpoint temperature control band region.

The supply air temperature control band is centeredaround supply air temperature setpoint and isadjustable from 2 to 12°F. In a steady state, the unit willeither maintain a constant level of cooling capacitywith the supply air temperature within the controlband, or the highest active cooling level will cycle toprovide an average supply air temperature equal to thesetpoint.

If the supply air temperature swings outside the limitsof the control band, the mechanical cooling capacitywill increase or decrease by one level accordingly. Thechange occurs by integrating the temperature offsetfrom the control band limit.

A minimum time delay of five minutes follows eachchange in cooling level. This time delay promotesstability by allowing the system to respond to thechange before any further control action occurs. As thesupply air temperature approaches setpoint, the timeduration between changing levels of cooling capacityincreases.

See Figure 54, p. 69 for the typical unit operating curve.Figure 55, p. 69 shows typical unit performance whensupply air temperature swings exceed the control bandlimits.

Adjust the supply air temperature control bandaccording to the desired unit performance. Increasingthe control band reduces the equipment cycle rate andincreases the maximum potential supply airtemperature deviation from setpoint. Conversely,decreasing the control band reduces the maximumpotential temperature deviation, but increases thecompressor cycle rate.

Follow these recommendations concerning the supplyair temperature control band settings based onexpected unit sizing:

• 2 Cooling stage unit: 9°F




SCXG-SVX01P-EN 69

Table 37. Compressor stages

Unit SizeRefrigerant CircuitType Model # Digit 5

Compressor HP byStage

StandardCompressor Staging

Lead/LagCompressor Staging

SCMor MCMA B

SXWG 20, 25 Independent 10 10 B/AB A/AB MCM

SXWG 30 Independent 15 10 B/A/AB A/AB MCM

SXWG 35SXRG 32 Independent 15 15 B/AB A/AB MCM

Figure 54. Typical pulldown curve for unit operatingproperly within control band

Figure 55. Typical pulldown curve for unit operatingimproperly outside control band

Compressor Safety DevicesIf a compressor low pressure cutout opens duringcompressor startup, the UCM will not shut thecompressor off during the first two to three minutesafter startup. This prevents possible nuisance tripsduring low ambient start conditions. See Table 38, p.69.

Each compressor’s discharge line contains a highpressure cutout. Under abnormal operating conditions,the cutout will open to stop compressor operation.

Table 38. Pressure cutouts (open/close)

Unit ModelHigh Pressure

CutoutLow Pressure

Cutout

SXWF 553/424 49/74

SXRF 650/500 36/61

Low Ambient Compressor LockoutThis function will lock out the compressor if theoutdoor air temperature sensor reads an outdoortemperature below the low ambient compressorlockout temperature setpoint. This setpoint isadjustable at the human interface panel. Compressorswill lock out when outdoor air temperature falls belowthat selected temperature and will start again when thetemperature rises 5°F above the setpoint.

Evaporator Coil Frost ProtectionFROSTATThe FROSTAT™ system eliminates the need for hot gasbypass. It utilizes an evaporator temperature sensormounted on the suction line near the TXV bulb of eachcircuit to protect the evaporator from freezing.

If the evaporator temperature approaches the specifiedsetpoint (adjustable between 25 and 35°F at the HI) thecompressor(s) will cycle off. The supply fan remains onto help de-ice the coil. The compressors will restartwhen the evaporator temperature has risen 10°F abovethe specified cutout temperature and when thecompressor(s) have been off a minimum of threeminutes. This prevents rapid cycling of thecompressors.

Service Valve OptionIf ordered, service valves are factory installed on eachcircuit before and after the compressor to allowcompressor isolation for servicing.

Waterside ComponentsWaterside components consist of water piping, watervalves, water flow switch option, water cooledcondensers (SXWF only), and the economizer option.


70 SCXG-SVX01P-EN

Water Purge

NNOOTTIICCEEPPrrooppeerr WWaatteerr TTrreeaattmmeenntt RReeqquuiirreedd!!TThhee uussee ooff uunnttrreeaatteedd oorr iimmpprrooppeerrllyy ttrreeaatteedd wwaatteerrccoouulldd rreessuulltt iinn ssccaalliinngg,, eerroossiioonn,, ccoorrrroossiioonn,, aallggaaee oorrsslliimmee..UUssee tthhee sseerrvviicceess ooff aa qquuaalliiffiieedd wwaatteerr ttrreeaattmmeennttssppeecciiaalliisstt ttoo ddeetteerrmmiinnee wwhhaatt wwaatteerr ttrreeaattmmeenntt,, iiffaannyy,, iiss rreeqquuiirreedd.. TTrraannee aassssuummeess nnoo rreessppoonnssiibbiilliittyyffoorr eeqquuiippmmeenntt ffaaiilluurreess wwhhiicchh rreessuulltt ffrroomm uunnttrreeaatteeddoorr iimmpprrooppeerrllyy ttrreeaatteedd wwaatteerr,, oorr ssaalliinnee oorr bbrraacckkiisshhwwaatteerr..

This user-definable feature allows the user to select apurge schedule to automatically circulate waterthrough the economizer and condensers periodicallyduring non-operational times. This allows freshchemicals to circulate in waterside heat exchangers.This feature is on all units and is defined at the HI.

Water Piping OptionsWater piping is factory-installed with left-handconnections on units without a waterside economizer.Units can be ordered with either basic piping orintermediate piping. Also, units with watersideeconomizers can be set for either variable or constantwater flow at the HI. See Figure 56, p. 71 and Figure57, p. 71 for detailed piping configuration information.

With compatible piping configurations, the unit can beconfigured to provide:

• Constant water flow with basic or intermediatepipingor

• Variable water flow (head pressure control) withintermediate piping only.

Constant water flow is for condenser pumping systemsthat are not capable of unloading the water-pumpingsystem. Variable water flow maximizes energy savingby unloading the water pumping system.

Basic Water PipingThis option is available on units without a watersideeconomizer and with condenser water applicationsabove 54°F (12.2°C) that do not require condensingpressure control. Left hand water connections andpiping are extended to the unit exterior. Manifoldpiping is factory installed.

Intermediate Water PipingThis option provides condensing temperature controlwhen the unit is configured (user defined at the HI) forvariable water flow with or without a watersideeconomizer. A two-way modulating control valve iswired and installed in the unit to maintains a specificrange of water temperature rise through the condenserwhen entering fluid temperature is less than 58°F (15°

C).This option allows the compressor to operate withentering fluid temperature down to 35°F (2°C).Theminimum valve position to maintain minimumcondenser flow rates is user-defined at the HI. Thisvalve drives closed if the unit shuts down or if a powerfailure occurs.

Water Flow Switch OptionA water flow switch is factory installed in thecondenser water pipe within the unit. Whenever theflow switch detects a water flow loss prior to or duringmechanical cooling, compressor operation locks outand a diagnostic code displays. If water flow isrestored, the compressor operation automaticallyrestores.

Water-Cooled CondensersUnits that are set up for variable water flow willmodulate a water valve to maintain a user-definedcondensing temperature setpoint. Condensingtemperature will be referenced utilizing factoryinstalled sensors located at each condenser.

Table 39. Condenser water piping connection sizes

Unit Size Inlet Pipe Outlet Pipe

SXWG 20, 25, 30, 32, 35 2 1/2 NPT 2 1/2 NPT

Waterside Economizer OptionThe waterside economizer option takes advantage ofcooling tower water to either precool the entering air toaid the mechanical cooling process or, if the watertemperature is low enough, provide total systemcooling. Waterside economizing enables when theunit’s entering water temperature is below the unit’sentering mixed air temperature by a minimum of 4°Fplus the economizer’s approach temperature. Theapproach temperature default is 4°F. Watersideeconomizing disables when the unit’s entering watertemperature is not below the unit’s entering mixed airtemperature by at least the water economizer approachtemperature. The approach temperature defaults to 4°F. The economizer acts as the first stage of cooling. Ifthe economizer is unable to maintain the supply airsetpoint, the unit control module brings oncompressors as required to meet the setpoint.

The waterside economizer includes a coil, modulatingvalves, controls, and piping with cleanouts. The coilconstruction is ½-inch (13 mm) OD seamless coppertubes expanded into aluminum fins. The evaporatorand economizer coils share a common sloped (IAQ)drain pan. Drain pan options are either galvanized orstainless steel, and are insulated and internallytrapped.

The waterside economizer coil is available with either atwo or four row coil, with no more than 12 fins per inch.


SCXG-SVX01P-EN 71

The tubes are arranged in a staggered pattern tomaximize heat transfer. The coil has round coppersupply and return headers with removable cleanoutand vent plugs. The optional mechanical cleanableeconomizer has removable cast iron headers to alloweasy mechanical cleaning of the tubes. The watersideworking pressure is rated for 400 psig (2758 kPa).

Waterside Economizer Flow ControlUnits equipped with a waterside economizer can be setfrom the human interface panel for variable or constantwater flow.

Constant Water Flow with IntermediatePipingTwo-way modulating control shutoff valves are wired,controlled, and installed in unit. One valve is located ineconomizer’s water inlet, and the other in condenserbypass water inlet. When waterside economizerenables, two-way valves modulate to maintaindischarge air temperature setpoint. As economizervalve opens, condenser bypass valve closes, and viceversa. Full water flow is always maintained throughcondensers. Both valves will close in event of a powerfailure.

Variable Water Flow with IntermediatePipingTwo-way modulating control shutoff valves are wired,controlled, and installed in the unit. One valve islocated in the economizer’s water inlet, and the other is

in the condenser water inlet. The economizer valve andthe condenser bypass valve modulate in- dependentlyof each other. When the economizer valve is active, allthe water flowing through the economizer exits into thecondensers. The software reads the saturatedcondenser water temperature for each circuit; trying tomaintain 100 degrees saturated condensertemperature. Whichever circuit is the furthest away(either above 120 degrees or below 80 degrees) drivesthe software to modulate the condenser bypass valveeither towards open or towards closed respectively.Eventually a balance will be reached until the saturatedcondenser temperatures change again. Both valvesclose whenever mechanical cooling is not required,and in the event of a power failure.

If the unit does not have a waterside economizer thenvariable water flow is automatically active withintermediate piping.

Figure 56. Basic water piping, constant water flow

Condenser 1

Condenser 2

Figure 57. Intermediate water piping, variable water flow (L) and Intermediate piping with waterside economizer,variable or constant water flow (R)

Condenser 1

Condenser 2V2

V2Condenser 2V1

Economizer

Condenser 1

Variable Water Flow Waterside EconomizerVariable or Constant Water Flow

Unit Airside ComponentsThe air delivery system consists of dampers, enthalpyswitch option, airside economizer option, filters, lowambient sensors, and factory mounted single or doublewall plenums.

Supply Air FanThe unit has two supply fans on a single shaft that runat a constant speed (CV). However, the fans may have

the VFD option with supply air temperature control(VAV) that modulates airflow based on supply air ductstatic pressure. Pressing the stop key on the HI will turnthe supply fan off. The fan is on continuously when aCV unit is in occupied mode and except when a unit isin the night heat/morning warm-up mode. During thenight heat and setback mode the fan cycles on and offin response to a call for heat.


72 SCXG-SVX01P-EN

Low Entering Air Temperature SensorThis is standard on all units with a hydronic coil orwaterside economizer. It can also be ordered as anoption.

A thermostat limit switch is factory mounted on theentering air side of the unit with a capillary tubeserpentine across the coil face. If the temperature fallsbelow 35°F (2°C), the fan shuts down and the watersideeconomizer and/or hydronic heat valve options open toallow full water flow. The heat output also energizes. Amanual reset is required. The low entering airtemperature setpoint is adjustable at the HI.

High Duct Temperature ThermostatA factory-supplied temperature limit switch with resetelement detects the supply air duct temperature. Thissensor should be field-installed downstream from thedischarge in the supply air duct. If the supply air ducttemperature exceeds 240°F (115.6°C), the unit shutsdown and displays a diagnostic. A manual reset isrequired at the unit. High duct temperature can beadjusted at thermostat.

Dirty Filter Sensor OptionA factory installed pressure switch senses the pressuredifferential across the filters. When the differentialpressure exceeds 0.9 inches (23 mm) WG, contactclosure occurs and the HI will display a diagnostic. Theunit will continue to run until you replace the air filters.

A field installed indicator device may be wired to relayterminals to indicate when filter service is required.Contacts are rated at 115 VAC and are powered by afield-supplied transformer.

Low Ambient Sensor (Air-Cooled Units)Low ambient sensor is field-installed on air-cooledunits. Position it in a location subject to ambienttemperatures only and not exposed to direct sunlightor exhaust fans.

The low pressure cutout initiates based on the ambienttemperature. A time delay on the low pressure cutoutinitiates for ambient temperatures between 50 (zerominutes) and 0°F (10 minutes).This helps to preventnuisance low pressure cutout trips.

Supply Air Static Pressure LimitThe opening of the VAV boxes coordinate during unitstartup and transition to/from occupied/unoccupiedmodes to prevent supply air duct over pressurization.However, if for any reason the supply air pressureexceeds the user-defined supply air static pressurelimit set at the HI panel, the supply fan VFD shutsdown. The unit will attempt to restart, up to threetimes. If the over pressurization condition still occurson the third restart, the unit shuts down and a manualreset diagnostic sets and displays at the HI.

Variable Frequency Drive OptionVariable frequency drive (VFD) is driven by amodulating 0-10 vdc signal from the RTM module. Apressure transducer measures duct static pressure, andthe VFD adjusts fan speed to maintain the supply airstatic pressure within an adjustable user-defined range.The range is determined by the supply air pressuresetpoint and supply air pressure dead band, which areset at the HI panel.

VFDs provide supply fan motor speed modulation. Thedrives will accelerate or decelerate as required tomaintain the supply air static pressure setpoint.

VFD with BypassBypass control is an option that provides full nominalairflow in the event of drive failure. The user mustinitiate the bypass mode at the HI panel. When inbypass mode, VAV boxes need to be fully open. Theself-contained unit will control heating and coolingfunctions to maintain setpoint from a user-defined zonesensor. Supply air static pressure limit is active in thismode.

For more detailed information on VFD operation,reference VFD technical manual that ships with theunit.

Airside Economizer OptionUnits with the airside economizer option are equippedwith the necessary control sequences to use outside airfor the first stage of cooling, in occupied or unoccupiedmode and when ambient conditions are favorable foreconomizing. Inherent in the unit controller is theability to suppress the setpoint below the normal unitsetpoint. This allows the building to improve comfortlevels when possible, and at the same time, optimizebuilding mechanical cooling operation for peakoperating efficiency. An outside air temperature andrelative humidity sensor are provided to allowmonitoring of reference enthalpy and are fieldinstalled.

If the unit has the ECEM board, economizer operationenables when the outside air enthalpy is less than 25BTUs/lb. default (adjustable 19-28 BTUs/lb). Duringoccupied mode, the outside air damper opens to 15%(adjustable 0-100% at the HI) for ventilation purposes.Also, the ability to alter the outside air damper positionto compensate for VAV supply air modulation isinherent in the unit controls, and can be enabled by theoperator.

If the unit does not have an ECEM board, it willeconomize when the O/A temperature falls below theO/A economizer setpoint.

The mixing box fabrication is galvanized steel.Opposed low leak damper blades are fabricated fromgalvanized steel and rotate on rustproof nylonbushings. A factory installed 24V modulating springreturn actuator controls both damper positions.


SCXG-SVX01P-EN 73

When outdoor conditions are not suitable foreconomizer cooling, the enthalpy control disables theeconomizer function and permits the outdoor airdamper to open only to the minimum position.

On water-cooled units, compressor operation lockoutwill not occur at low ambient air temperatures.However, lockout will still occur via low condenserwater temperature.

The outdoor air dampers drive fully closed wheneverthe supply air fan is off, provided there is power to theunit.

Comparative Enthalpy ControlComparative enthalpy controls the economizeroperation and measures temperature and humidity ofboth return air and outside air to determine whichsource has lower enthalpy. This allows truecomparison of outdoor air and return air enthalpy bymeasurement of outdoor air and return airtemperatures and humidities. A factory-installedcontrol board, with field-installed outside and return airtemperature and relative humidity sensors, allowsmonitoring of outside and return air.

NNoottee:: If comparative enthalpy is not ordered, standardmethod is to compare outdoor air enthalpy withthe fixed reference enthalpy. The referenceenthalpy is set through the human interfacepanel.

Units with comparative enthalpy control are equippedwith the necessary control sequences to allow usingoutside air for the first stage of cooling, in occupied orunoccupied mode and when ambient conditions arefavorable for economizing. Inherent in the unitcontroller is the ability to suppress the setpoint belowthe normal unit setpoint. This allows building toimprove comfort levels when possible, and at the sametime, optimize building mechanical cooling operationfor peak efficiency.

Economizer operation enables when the outside airenthalpy is 3 BTU/lb less than the return air enthalpy.During occupied mode, the outside air damper opensto 15% (adjustable 0-100%) for ventilation purposes.Also, the ability to alter the outside air damper positionto compensate for VAV supply air modulation isinherent in the unit controls, and can be enabled by theoperator.

The mixing box fabrication is galvanized steel.Opposed low leak damper blades are fabricated fromgalvanized steel and rotate on rustproof nylonbushings. A factory installed 24V modulating springreturn actuator controls both damper positions.

Airside Economizers with Traq DamperOutside air enters the unit through the Traq™ damperassembly and is measured by velocity pressure flowrings. The velocity pressure flow rings are connected toa pressure transducer/solenoid assembly, which

compensates for temperature swings that could affectthe transducer. The ventilation control module (VCM)utilizes the velocity pressure input, the RTM outdoor airtemperature input, and the minimum outside air cfmsetpoint to modify the volume (cfm) of fresh airentering the unit as the measured airflow deviates fromsetpoint.

When the optional preheat temperature sensor isinstalled at the auxiliary temperature on the VCM andthe preheat function is enabled, the sensor will monitorthe combined (averaged) fresh air and return airtemperatures. As this mixed air temperature fallsbelow the preheat actuate temperature setpoint, theVCM activates the preheat binary output to control afield-installed heater. The output deactivates when thetemperature rises 5°F above the preheat actuatetemperature setpoint.

Using a field-installed CO2 sensor with CO2 resetenabled, as the CO2 concentration increases above theCO2 reset start value, the VCM modifies the minimumoutside air cfm setpoint to increase the amount of freshair entering the unit. The setpoint adjusts upward untilreaching the CO2 maximum reset value. The maximumeffective (reset) setpoint value for fresh air is limited tothe system’s operating cfm. As the CO2 concentrationdecreases, the effective (reset) setpoint value adjustsdownward toward the minimum outside air cfmsetpoint. See CO2 reset figure below for an airflow cfmvs. CO2 concentration curve.

Figure 58. CO2 reset function, outside air vs. CO2

IncreasingConcentration

Carbon Dioxide Reset

MaximumAirflow

IncreasingReset Amount

O.A CFMSetpoint

Carbon DioxideReset Start

Carbon DioxideMaximum Reset

Standard Two-Position Damper InterfaceUnits with the two-position damper interface areprovided with a 0-10 VDC control output suitable forcontrolling a field-provided modulating actuator. Inoccupied mode, the output drives to the maximumposition.

Airside Economizer InterfaceUnits with airside economizer interface are equippedwith the necessary control sequences to allow usingoutside air for first stage of cooling, in occupied orunoccupied mode and when ambient conditions arefavorable for economizing. Inherent in unit controller isthe ability to suppress setpoint below normal unitsetpoint. This allows the building to improve comfort


74 SCXG-SVX01P-EN

levels when possible, and at the same time, optimizebuilding mechanical cooling operation for peakoperating efficiency. An outside air temperature andrelative humidity sensor are provided for fieldinstallation to monitor reference enthalpy. Economizeroperation enables when the outside air enthalpy is lessthan 25 BTu/lb (adjustable 19-28 BTu/lb.). Duringoccupied mode, the outside air damper opens to 15%(adjustable 0-100%) for ventilation purposes. Also, theability to alter the outside air damper position tocompensate for VAV supply air modulation is inherentin the unit controls, and can be enabled by theoperator. An analog 2-10VDC output (adjustable (0-10VDC) is provided to modulate the field-provided 30second damper actuators (adjustable 1-255 seconds).

Airside Economizer Interface withComparative EnthalpyUnits with airside economizer interface andcomparative enthalpy are equipped with the necessarycontrol sequences to allow using outside air for the firststage of cooling, in occupied or unoccupied mode andwhen ambient conditions are favorable foreconomizing. Inherent in the unit controller is theability to suppress the setpoint below the normal unitsetpoint. This allows the building to improve comfortlevels when possible, and at the same time, optimizebuilding mechanical cooling operation for peak

operating efficiency. A factory-installed control board,with outside and return air temperature and relativehumidity sensors, are provided for monitoring outsideand return air. The sensors are field installed.Economizer operation enables when the outside airenthalpy is 3 BTU’s/lb. less than the return air enthalpy.During occupied mode, the outside air damper opensto 15% (adjustable 0-100%) for ventilation purposes.Also, the ability to alter the outside air damper positionto compensate for VAV supply air modulation isinherent in the unit controls, and can be enabled by theoperator. An analog 2-10 VDC output (adjustable (0-10VDC) is provided to modulate the field-provided 30-second damper actuators (adjustable 1-255 seconds).

Air-Cooled CondensersModel SXRGunits are designed for use with the remoteair-cooled condenser, model CXRC. For moreinformation, see the Installation, Owner, andMaintenance Manual for Air-cooled Condenser, CXRC-SVX01*-EN. See for CXRC refrigerant connection sizes.

Condenser fans will stage per a user-defined setting. Ifthe condenser is equipped with head pressure control(air modulation on last stage of condenser capacity),the condenser airflow will modulate to maintaincondensing temperature setpoint. Condensingtemperature is determined by sensors located at eachcondenser coil.


SCXG-SVX01P-EN 75

ControlsPoints ListRTMModule

Binary Inputs• Emergency stop

• External auto/stop

• Unoccupied/occupied

• Dirty filter

• VAV changeover with hydronic heat

Binary Outputs• VAV box drive max (VAV units only)

• CV unoccupied mode indicator (CV units only)

• Alarm

• Fan run request

• Water pump request (water-cooled only)

Analog Input• Airside economizer damper minimum position

Analog Output• Outside air damper actuator

Heat Module:• Analog output

GBAS Module

Binary Inputs• Demand limit contacts

Binary Outputs• Dirty filter relay

• Refrigeration fail relay

• Heat fail relay

• Supply fan fail relay

• Active diagnostics

Analog inputs• Occupied zone cooling setpoint

• Occupied zone heating setpoint

• Unoccupied zone cooling setpoint

• Unoccupied zone heating setpoint or minimumoutside air flow setpoint

• Supply air cooling setpoint

• Supply air heating setpoint

• Supply air static pressure setpoint

ECEMModule

Analog Inputs• Return air temperature

• Return air humidity

IInn aaddddiittiioonn,, uunniittss wwiitthh aa VVOOMM hhaavvee::

Binary Inputs• VOM mode A, unit off

• VOM mode B, pressurize

• VOM mode C, exhaust

• VOM mode D, purge

• VOM mode E, purge w/duct pressure control

Binary Output• V.O. relay

LCI-I Points ListRefer to the LonTalk™ Communications Interface forIntellipak and Commercial Self-Contained IntegrationGuide, BAS-SVP02*-EN.

Phase MonitorUnit is equipped with phase monitor in control box.The phase monitor will protect against phase loss,imbalance and reversal of line voltage. If a fault occurs,the red LED will energize. While the fault condition ispresent, the phase monitor interrupts the 115V controlcircuit. If no faults are observed, a green LED will beenergized.

Unit Control ComponentsThe self-contained unit is controlled by amicroelectronic control system that consists of anetwork of modules. These modules are referred to asunit control modules (UCM). In this manual, theacronym UCM refers to the entire control systemnetwork.

These modules perform specific unit functions usingproportional/integral control algorithms. They aremounted in the unit control panel and are factory wiredto their respective internal components. Each modulereceives and interprets information from other unitmodules, sensors, remote panels, and customer binarycontacts to satisfy the applicable request; i.e.,economizing, mechanical cooling, heating, ventilation.

Following is a detailed description of each module’sfunction.

76 SCXG-SVX01P-EN

RTMModule Board—Standard on allUnitsThe RTM responds to cooling, heating, and ventilationrequests by energizing the proper unit componentsbased on information received from other unitmodules, sensors, remote panels, and customersupplied binary inputs. It initiates supply fan, exhaustfan, exhaust damper, or variable frequency driveoutput, and airside economizer operation based on thatinformation.

Reference the RTM points list on page 70.

NNoottee:: Emergency stop and external auto/stop, stop theunit immediately, emergency stop generates amanual reset diagnostic that must be reset at theunit human interface. External auto-stop willreturn the unit to the current operating modewhen the input is closed, so this input is autoreset.

RTM Remote Economizer Minimum PositionThe remote minimum position potentiometer,BAYSTAT023A, provides a variable resistance (0-270ohms) to adjust the economizer minimum positionfrom 0 to 100% when connected to the economizerremote minimum position input of the RTM. The RTMmust be selected as the source for economizerminimum position. If the RTM is the selected source foreconomizer minimum position, and if a valid resistanceper the table below is provided to the RTM remoteminimum position input, the OA cfm compensationfunction will not operate, even if enabled. “Default” isthe only possible source for economizer minimumposition when using the OA cfm compensationfunction.

Table 40. Economizer remote minimum positioninput resistance

Input Resistance Economizer Min. Position

0 - 30 ohms 0%

30 - 240 ohms 0-100% (linear)

240 - 350 ohms 100%

> 350 ohms N/A

Note: A resistance greater than 350 ohms is assumed to be anopen circuit. The system will use the default minimumposition value.

RTM Analog OutputsThe RTM has two 0-10 Vdc outputs: one for the supplyfan and one for the economizer option. These outputsprovide a signal for one or two damper actuators.There are no terminal strip locations associated withthese wires. They go directly from pins on RTM circuitboard to actuator motor.

RTM Binary OutputsThe RTM has an output with pressure switch provinginputs for the supply fan. There is a 40 second delayfrom when the RTM starts the supply fan until the fanproving input must close. A fan failure diagnostic willoccur after 40 seconds. This is a manual resetdiagnostic, and all heating, cooling, and economizerfunctions will shut down. If this proving input isjumped, other nuisance diagnostics will occur. If theproving input fails to close in 40 seconds, theeconomizer cycles to the minimum position. This is amanual reset diagnostic. External control of the fan isnot recommended.

VAV Drive Max OutputThis is a single-pole, double-throw relay rated at amaximum voltage of 24 Vac, two amps. The relaycontacts of this relay switch when the unit goes fromthe occupied mode to the unoccupied mode by meansof the occupied binary input. The contacts will stayswitched during the unoccupied and morning warm-upmode. They will return to the position shown on theunit wiring diagram when the unit returns to theoccupied mode. This binary output signals the VAVboxes or other terminal devices to go full open.

RTM Alarm RelayThis is a single pole, double throw relay rated at amaximum voltage of 24 Vac, two amps max. Relaycontacts can be programmed from the unit humaninterface. This relay can be programmed to pick up onany one or group of diagnostics from the unit humaninterface.

Status/Annunciator OutputThe status annunciator output is an internal functionwithin the RTM module on CV and VAV units. Itprovides:

• Diagnostic and mode status signals to the remotepanel (LEDs) and to the Human Interface.

• Control of the binary alarm output on the RTM.

• Control of the binary outputs on the GBAS moduleto inform the customer of the operational statusand/or diagnostic conditions.

Occupied/Unoccupied InputsThere are four (4) ways to switch to occupied/unoccupied:

• Field-supplied contact closure hard wired binaryinput to the RTM.

• Programmable night setback zone sensor.

• Tracer Summit.

• Factory-mounted time clock.

VAV Changeover ContactsThese contacts are connected to the RTM whendaytime heating on VAV units with internal or external

CCoonnttrroollss

SCXG-SVX01P-EN 77

hydronic heat is required. Daytime (occupied) heatingswitches the system to a CV unit operation. Refer to theunit wiring diagram for the field connection terminalsin the unit control panel. The switch must be rated at 12mA @ 24 Vdc minimum.

External Auto/Stop SwitchA field-supplied switch may be used to shut down unitoperation. This switch is a binary input wired to theRTM. When opened, the unit shuts down immediatelyand can be canceled by closing the switch. Refer to theunit wiring diagrams (attached to the unit controlpanel) for proper connection terminals. The switchmust be rated for 12 mA @ 24 Vdc minimum. Thisinput will override all VOM inputs, if the VOM option ison the unit.

Occupied/Unoccupied ContactsTo provide night setback control if a remote panel withnight setback was not ordered, install a field-suppliedcontact. This binary input provides the building’soccupied/unoccupied status to the RTM. It can beinitiated by a time clock, or a building automationsystem control output. The relay’s contacts must berated for 12 mA @ 24 Vdc minimum. Refer to theappropriate wiring diagrams (attached to the unitcontrol panel for the proper connection terminals in theunit control panel.

Emergency Stop InputA binary input is provided on the RTM board forinstallation of a field-supplied normally closed (N.C.)switch to use during emergency situations to shutdown all unit operations. When open, an immediateshutdown occurs. An emergency stop diagnosticenters the human interface and the unit will require amanual reset. Refer to the unit wiring diagrams(attached to the unit control panel for the properconnection terminals. The switch must be rated for 12mA @ 24 Vdc minimum. This input will override allVOM inputs, if the VOM option is on the unit.

VAV Box OptionTo interlock VAV box operation with evaporator fanand heat/cool modes, wire the VAV boxes/air valves toVAV box control connections on the terminal block.

Supply Duct Static Pressure ControlThe RTM relies on input from the duct pressuretransducer when a unit is equipped with VFD to set thesupply fan speed to maintain the supply duct staticpressure to within the static pressure setpoint deadband.

RTM SensorsRTM sensors include: zone sensors with or withoutsetpoint inputs and modes, supply air sensor, ductstatic pressure, outside air temperature, outside airhumidity, airflow proving, and dirty filter.

Table 41. RTM sensor resistance vs. temperature

Temp °F ResistanceV ohms

Temp °F ResistanceV ohms

-40 346.1 71 11.60

-30 241.7 72 11.31

-20 170.1 73 11.03

-10 121.4 74 10.76

-5 103.0 75 10.50

0 87.56 76 10.25

5 74.65 77 10.00

10 63.8 78 9.76

15 54.66 79 6.53

20 46.94 80 9.30

25 40.40 85 8.25

30 34.85 90 7.33

35 30.18 100 5.82

40 26.22 105 5.21

45 22.85 110 4.66

50 19.96 120 3.76

55 17.47 130 3.05

60 15.33 140 2.50

65 13.49 150 2.05

66 13.15 160 1.69

67 12.82 170 1.40

68 12.50 180 1.17

69 12.19 190 0.985

70 11.89 200 0.830

Table 42. RTM setpoint analog inputs

Cooling or HeatingSetpoint Input, °F (using

RTM as zone temp.source) ohms

Cooling Setpoint Input, °F(using RTM as supply air

temp. source)resistance, V

40 40 1084

45 45 992

50 50 899

55 55 796

60 60 695

65 65 597

70 70 500

75 75 403

80 80 305

NA 85 208

NA 90 111

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Table 43. RTM resistance value vs. system operatingmode

Resistance appliedto RTMmode inputterminals, ohms

CV Units VAVUnits

Fanmode

Systemmode

Systemmode

2320 auto off off

4870 auto cool

7680 auto auto auto

10,770 on off

13,320 on cool

16,130 on auto

19,480 auto heat

27,930 on heat

Note: Mode boundaries are 1000 to 40,000 ohms. Otherboundaries are equal to the midpoint between thenominal mode resistance.

Compressor Module(MCM - Standard on all units)

The Compressor module, upon receiving a request formechanical cooling, energizes the appropriatecompressors and condenser fans. It monitors thecompressor operation through feedback information itreceives from various protection devices.

Human Interface Module—Standard onall UnitsThe human interface (HI) module enables the operatorto adjust the operating parameters for the unit using its16-key keypad on the human interface panel. The HIpanel provides a two line, 40 character, clear language(English, Spanish, or French) LCD screen with unitstatus information and menus to set or modifyoperating parameters. It is mounted in the unit’s maincontrol panel and accessible through the unit’s controlpanel door.

Remote Human Interface Module OptionThe optional remote-mount human interface (RHI)panel has all the functions of the unit-mounted versionexcept for service mode. To use a RHI, the unit must beequipped with an optional interprocessorcommunications bridge (IPCB). Model number digit 32(=2) indicates if the ICPB was ordered with the unit. Ifnot, contact your local Trane representative to order anICPB kit for field installation. The RHI can be located upto 1,000 feet (304.8 m) from the unit. A single RHI canmonitor and control up to four self-contained units ifeach one contains an IPCB. The IPCB switches must beset as SW1–off, SW2–off, and SW3–on.

Interprocessor Communications Board(IPCB - Optional used with the Optional Remote HumanInterface)

The Interprocessor Communication Board expandscommunications from the rooftop unit UCM network toa Remote Human Interface Panel. DIP switch settingson the IPCB module for this application should be;Switches 1 and 2 “Off”, Switch 3 “On”.

Waterside Module—Standard on AllWater-cooled UnitsThe waterside module (WSM) controls all water valvesbased on unit configuration. In addition, the WSMmonitors waterflow proving and the followingtemperatures:

• Entering water

• Entering air low

• Mixed air

• Entering condenser water

• Refrigerant circuit 3:

– Saturated condenser

– Evaporator frost

• Refrigerant circuit 4:

– Condenser

– Evaporator

Cooling Tower InterlockTo interlock condenser pump/tower with coolingoperation, wire the cooling tower to an external 115volt control power source, to ground, and to controlterminal block. Normally open/closed contacts areprovided.

Heat ModuleThe heat module is standard on all units with factory-installed heat. It controls the unit heater to stage upand down to bring the temperature in the controlledspace to within the applicable heating setpoint. Also, itincludes a freezestat, morning warm-up, and heatingoutputs.

Ventilation Override Module (VOM)OptionThe ventilation override module can be field-configured with up to five different override sequencesfor ventilation override control purpose. When any oneof the module’s five binary inputs are activated, it willinitiate specified functions such as: spacepressurization, exhaust, purge, purge with ductpressure control, and unit off.

Once the ventilation sequences are configured, theycan be changed unless they are locked using the HI.

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SCXG-SVX01P-EN 79

Once locked, the ventilation sequences cannot beunlocked.

The compressors and condenser fans disable duringthe ventilation operation. If more than one ventilationsequence activates, the one with the highest priority(VOM “A”) begins first, with VOM “E” having lowestpriority and beginning last.

A description of the VOM binary inputs follows below.

UNIT OFF Sequence “A”When complete system shut down is required, thefollowing sequence can be used.

• Supply fan—off

• Supply fan VFD—off (0 Hz)

• Outside air dampers—closed

• Heat—all stages—off, modulating heat output at 0Vdc

• Occupied/Unoccupied output—de-energized

• VO relay—energized

• Exhaust fan (field provided -installed)—off

• Exhaust damper (field provided -installed)—closed

PRESSURIZE Sequence “B”This override sequence can be used if a positivelypressured space is desired instead of a negativelypressurized space.

• Supply fan—on

• Supply fan VFD—on (60 Hz)/VAV boxes— open

• Outside air dampers—open

• Heat—all stages—off, hydronic heat output at 0 Vdc

• Occupied/ unoccupied output—energized


• Exhaust fan (field provided -installed)—off

• Exhaust damper (field provided -installed)—closed

EXHAUST Sequence “C”With the building’s exhaust fans running and the unit’ssupply fan off, the conditioned space becomesnegatively pressurized. This is desirable for clearing thearea of smoke when necessary; i.e. from anextinguished fire, to keep smoke out of areas that werenot damaged.

• Supply fan—off

• Supply fan VFD—off (0 Hz)

• Outside air dampers—closed


• Occupied/Unoccupied output—de-energized


• Exhaust fan (field provided -installed)—on

• Exhaust damper (field provided -installed)—open

PURGE Sequence “D”This sequence can purge the air out of a buildingbefore coming out of unoccupied mode of operation ina VAV system. Also, it can be used to purge smoke orstale air.

• Supply fan—on

• Supply fan VFD—on (60 hz)/VAV boxes—open

• Outside air damper—open

• Heat—all stages—off, modulating heat output at 0Vdc

• Occupied/Unoccupied output—energized




PURGE with Duct Pressure Control “E”This sequence can be used when supply air control isrequired for smoke control.

• Supply fan—on

• Supply fan VFD—on (if equipped)

• Outside air dampers—open


• Occupied/unoccupied output—energized




NNoottee:: Each system (cooling, exhaust, supply air, etc.)within the unit can be redefined in the field foreach of the five sequences, if required. Also thedefinitions of any or all of the five sequences canbe locked into the software by simple key strokesat the human interface panel. Once locked intothe software, the sequences cannot be changed.

Trane Communications Modules

Lontalk®/BACnet® CommunicationInterface Module(LCI/BCI - Optional - used on units with Trane ICS™ or3rd party Building Automation Systems)

The LonTalk/BACnet Communication Interfacemodules expand communications from the unit UCMnetwork to a Trane Tracer Summit™ or a 3rd partybuilding automation system and allow externalsetpoint and configuration adjustment and monitoringof status and diagnostics.

The LCI-I (Lontalk) utilizes an FTT-10A Free Topologytransceiver, which supports non-polarity sensitive, freetopology wiring, which allows the system installer toutilize star, bus, and loop architectures. This controllerworks in standalone mode, peer-to-peer with one ormore other units, or when connected to a Trane Tracer

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80 SCXG-SVX01P-EN

Summit or a third party building automation systemthat supports LonTalk.

The BCI-I (BACnet) utilizes the BACnet defined MS/TPprotocol as defined in ASHRAE standard 135-2004. Thiscontroller works in standalone mode, with Tracer SC®or when connected to a third party building automationsystem that supports BACnet.

Exhaust/Comparative Enthalpy Module(ECEM - Optional used on units with Statitrac and/orcomparative enthalpy options)

The Exhaust/Comparative Enthalpy module receivesinformation from the return air humidity sensor, theoutside air humidity sensor, and the return airtemperature sensor to utilize the lowest possiblehumidity level when considering economizeroperation. In addition, it receives space pressureinformation which is used to maintain the spacepressure to within the setpoint control band. Refer toFigure 59, p. 80 for humidity vs. voltage values.

Figure 59. Relative humidity vs. voltage

Figure 60. Velocity pressure transducer/solenoidassembly

Tube from low side of Transducer

PressureTransducer

VentilationControl Module

SolenoidTube from high sideof Transducer

Tube from low sideof Velocity Ring

Ventilation Control Module (VCM)((AAvvaaiillaabbllee oonnllyy wwiitthh TTrraaqq™™ ddaammppeerr ooppttiioonn))

The ventilation control module (VCM) is located in theairside economizer section of the unit and linked to theunit’s UCM network. Using a velocity pressuretransducer/solenoid (pressure sensing ring) in the freshair section allows the VCM to monitor and control freshair entering the unit to a minimum airflow setpoint. See

Figure 59, p. 80 for a detail view of the velocitypressure transducer/solenoid assembly.

An optional temperature sensor can be connected tothe VCM to enable control of a field installed fresh airpreheater.

Also, a field-provided CO2 sensor can be connected tothe VCM to control CO2 reset. The reset functionadjusts the minimum cfm upward as the CO2concentrations increase. The maximum effective (reset)setpoint value for fresh air entering the unit is limitedto the system’s operating cfm. Table 44, p. 80 lists theminimum outside air cfm vs input voltage.

Table 44. Minimum outside air setpoint w/VCMmodule and Traq™ sensing

Unit Input Volts CFM

SXWG 20 0.5 - 4.5 vdc 6,350-8,500

SXWG 25 0.5 - 4.5 vdc 7,250-10,625

SXWG 30 0.5 - 4.5 vdc 7,250-12,750

SXWG 35 0.5 - 4.5 vdc 7,250-14,875

SXRG 32 0.5 - 4.5 vdc 7,250-13,600

Generic Building Automation SystemModule OptionGeneric building automation system module (GBAS)provides broad control capabilities for buildingautomation systems other than Trane’s Tracer®system. A field provided potentiometer or a 0-5 Vdcsignal can be applied to any inputs of GBAS to providefollowing points:

GBAS Analog InputsFour analog inputs that can be configured to be any ofthe following:

• Occupied zone cooling

• Unoccupied zone cooling

• Occupied zone heating

• Unoccupied zone heating

• SA cooling setpoint

• SA heating setpoint

• Space static pressure setpoint

• SA static pressure setpoint

GBAS Binary OutputsFive binary outputs to provide diagnostics, signaling upto five alarms. Each of the five relay outputs can bemapped to any/all of the available diagnostics. Eachoutput contains a dry N.O. and N.C. contact with a VArating of 2 amps at 24 Vac.

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SCXG-SVX01P-EN 81

GBAS Binary InputOne binary input for the self-contained unit to use thedemand limit function. This function is operational onunits with a GBAS and is used to reduce electricalconsumption at peak load times. Demand limiting canbe set at either 50% or 100%. When demand limiting isneeded, mechanical cooling and heating (with field-provided 2-stage electric heat only) operation are eitherpartially (50%), or completely disabled (100%) to saveenergy. The demand limit definition is user definable atthe HI panel. Demand limit binary input accepts a fieldsupplied switch or contact closure. When the need fordemand limiting has been discontinued, the unit’scooling/heating functions will again become fullyenabled.

GBAS Communication (Analog Inputs)The GBAS accepts external setpoints in the form ofanalog inputs for cooling, heating, supply air pressure.Refer to the unit wiring diagram for GBAS input wiringand the various desired setpoints with thecorresponding DC voltage inputs.

Any of the setpoint or output control parameters can beassigned to each of the four analog inputs on the GBASmodule. Also, any combination of the setpoint and/oroutput control parameters can be assigned to theanalog inputs through the HI. To assign the setpoints,apply an external 0-5 Vdc signal to one of the following:

• Directly to the signal input terminals

• To the 5 Vdc source at the GBAS module with a 3-wire potentiometer.

NNoottee:: There is a regulated 5 Vdc output on the GBASmodule that can be used with a potentiometer asa voltage divider. The recommendedpotentiometer value is 1000-100,000 ohms.

The setpoints are linear between the values shown inTable 45, p. 82. Reference Table 46, p. 82 forcorresponding input voltage setpoints. Following areformulas to calculate input voltage or setpoint. SP =setpoint, IPV = input voltage.

• IIff tthhee sseettppooiinntt rraannggee iiss 5500--9900°°FF::

– IPV = (SP - 50) (0.1) + 0.5

– SP = [(IPV - 0.5)/0.1] + 50


– IPV = (SP - 40)(0.8) + 0.5

– SP = [(IPV - 0.5)/0.08] + 40


– IPV = (SP - 40)(0.029) + 0.5

– SP = [(IPV - 0.5)/0.029] + 40

• IIff tthhee ssttaattiicc pprreessssuurree rraannggee iiss 00..0033--00..33 iiwwcc::

– IPV = (SP - 0.03)(14.8) + 0.5

– SP = [(IPV - 0.5)/14.8] + 0.03

• IIff tthhee ssttaattiicc pprreessssuurree rraannggee iiss 00..00--55..00 iiwwcc::

– IPV = (SP)(0.8) + 0.5

– SP = [IPV/(0.8 + 0.5)]

GBAS Demand Limit Relay (Binary Input)The GBAS allows the unit to utilize the demand limitfunction by using a normally open (N.O.) switch to limitthe electrical power usage during peak periods.Demand limit can initiate by a toggle switch closure, atime clock, or an ICS control output. These contactsmust be rated for 12 ma @ 24 Vdc minimum.

When the GBAS module receives a binary input signalindicating demand limiting is required, a commandinitiates to either partially (50%) or fully (100%) inhibitcompressor and heater operation. This can be set at theHI using the setup menu, under the “demand limitdefinition cooling” and “demand limit definitionheating” screens. A toggle switch, time clock, orbuilding automation system control output can initiatedemand limiting.

If the cooling demand limit is set to 50%, half of thecooling capacity will disable when the demand limitbinary input closes. The heating demand limitdefinition can only be set at 100%, unless the unit hasfield-provided two-stage electric heat. In that case, ifthe heating demand limit is set to 50%, half or onestage of heating disables when the demand limit binaryinput closes. If the demand limit definition is set to100%, then all cooling and/or heating will disable whenthe demand limit input closes.

GBAS Diagnostics (Binary Outputs)The GBAS can signal up to five alarm diagnostics,which are fully mappable through the setup menu onthe HI. These diagnostics, along with the alarm outputon the RTM, allow up to six fully mappable alarmoutputs.

Each binary output has a NO and NC contact with arating of two amps at 24 Vac. The five binary outputsare factory preset as shown on the unit wiring diagram(on the unit control panel door). However, theseoutputs can be field defined in a variety ofconfigurations, assigning single or multiple diagnosticsto any output.

For a complete listing of possible diagnostics, see theSelf-Contained Programming Guide, PKG-SVP01. Forterminal strip locations, refer to the unit wiring diagramfor the GBAS.

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Table 45. GBAS analog input setpoints

Control Parameter Signal Range Vdc Setpoint Range °F

Occupied zone cooling setpoint (CV units only) 0.5 to 4.5 50 to 90°F

Unoccupied zone cooling setpoint (CV and VAV) 0.5 to 4.5 50 to 90°F

Occupied zone heating setpoint (CV units only) 0.5 to 4.5 50 to 90°F

Unoccupied zone heating setpoint (CV and VAV) 0.5 to 4.5 50 to 90°F

Supply air cooling setpoint (VAV units only) 0.5 to 4.5 40 to 90°F

Supply air hydronic heating setpoint (VAV units only) 0.5 to 4.5 40 to 180 F

Space static pressure setpoint 0.5 to 4.5 0.03 to 0.30 IWC

Supply air pressure setpoint (VAV units only) 0.5 to 4.5 0.0 to 5.0 IWC

Notes:1. Input voltages less than 0.5 Vdc are considered as 0.5 Vdc input signal is lost, the setpoint will "clamp" to the low end of the setpoint scale. No

diagnostic will result from this condition.2. Input voltages greater than 4.5 Vdc are considered to be 4.5 Vdc.3. The actual measured voltage is displayed at the HI.

Table 46. GBAS input voltage corresponding setpoints

Volts Temp. °F Volts Temp. °F Volts Temp. °F Volts Temp. °F

0.5 50 1.6 60 2.6 70 2.7 80

0.6 51 1.7 61 2.7 71 2.8 81

0.7 52 1.8 62 2.8 72 2.9 82

0.8 53 1.9 63 2.9 73 3.0 83

0.9 54 2.0 64 3.0 74 3.1 84

1.0 55 2.1 65 3.1 75 3.2 85

1.1 56 2.2 66 3.2 76 3.3 86

1.2 57 2.3 67 3.3 77 3.4 87

1.3 58 2.4 68 3.4 78 3.5 88

1.5 59 2.5 69 3.5 79 3.6 89

1.6 60 — — — — — —

1.7 61 — — — — — —

1.8 62 — — — — — —

1.9 63 — — — — — —

2.0 64 — — — — — —

2.1 65 — — — — — —

2.2 66 — — — — — —

2.3 67 — — — — — —

2.4 68 — — — — — —

Input Devices and System FunctionsFollowing are basic input device and system functiondescriptions used within the UCM network on self-contained units. Refer to the unit wiring diagrams forspecific connections.

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Water Purge


During the unoccupied mode, water-cooled units willperiodically circulate water through the condensersand waterside economizer if the user has enabled thepurge function at the HI. The water purge functioncirculates water to introduce fresh water-treatmentchemicals and help prevent water stagnation. Thenumber of hours between each periodic purge, orpurge duration, is user-defined at the HI between 1-999hours. If the periodic purge timer expires while the unitis in occupied mode, it will wait for the next availableunoccupied time before initiating water purge.Contrary, if a request for cooling occurs during a purgesequence, purge will terminate and cooling willcommence.

Compressor Circuit BreakersThe Scroll Compressors are protected by circuitbreakers which interrupt the power supply to thecompressors if the current exceeds the breakers “musttrip” value. During a request for compressor operation,if the Compressor Module detects a problem outsidenormal parameters, it turns any operating compressor(s) on that circuit “Off”, locks out all compressoroperation for that circuit, and initiates a manual resetdiagnostic.

Low Pressure ControlLow pressure (LP) control is accomplished using abinary input device mounted on the suction line, nearthe compressor. If suction pressure drops to 49 (water-cooled), 36 (air-cooled) ± 6 psig, or below, the switchopens.

If the switch is open at start, no compressors on thatcircuit will operate. They are locked out and a manualreset diagnostic initiates. If the LP switch opens after acompressor start, all compressors on that circuit willstop and remain off a minimum 3 minutes beforerestarting. If the LP cutout trips four times in the firstthree minutes of operation, all compressors on thatcircuit lockout and a manual reset diagnostic initiates.

LP switches close at 74 (water-cooled) and 61 (air-cooled)± 6 psig.

Evaporator Temperature Sensor FrostatThe evaporator temperature sensor is an analog inputdevice used to monitor refrigerant temperature insidethe evaporator coil to prevent coil freezing. It isattached to the suction line near the evaporator coilwith circuits 1 and 2 connected to the SCM/MCM andcircuits 3 and 4 connected to the WSM. The coil frostcutout temperature is factory set at 30°F. It is adjustableat the HI from 25-35°F. The compressors stage off asnecessary to prevent icing. After the last compressorstages off, the compressors will restart when theevaporator temperature rises 10°F above the coil frostcutout temperature and the minimum three minute“off” time elapses.

Saturated Condenser Temperature SensorsThe saturated condenser temperature sensors areanalog input devices. They are mounted inside atemperature well located on a condenser tube bend onair-cooled units, and in the condenser shell on water-cooled units. The sensors monitor the saturatedrefrigerant temperature inside the condenser coil andare connected to the SCM/MCM for circuits 1 and 2 (airor water cooled), and WSM for circuits 3 and 4 (onlywater-cooled).

Head Pressure ControlHead pressure control is accomplished using twosaturated refrigerant temperature sensors on air-cooled units and up to four sensors on water-cooledunits.

AAiirr--ccoooolleedd uunniittss:: During a request for compressoroperation when the condensing temperature risesabove the lower limit of the control band, thecompressor module (SCM/MCM) sequences condenserfans on. If the operating fans cannot bring thecondensing temperature to within the control band,more fans turn on. As the saturated condensingtemperature approaches the lower limit of the controlband, fans sequence off. The minimum on/off time forcondenser fan staging is 5.2 seconds. If the system isoperating at a given fan stage below 100% for 30minutes the saturated condensing temperature isabove the efficiency check point setting, a fan stage willbe added. If the saturated condensing temperature fallsbelow the efficiency check point setting, fan controlremains at the present operating stage. If the fan stagecycles four times within a 10 minute period, the lowerlimit temperature is redefined as being equal to thelower limit minus the temporary low limit suppressionsetting. The unit will utilize this new low limittemperature for one hour to reduce condenser fanshort cycling.

WWaatteerr--ccoooolleedd:: Units without WSE, the condenservalve modulates to maintain an average saturatedcondenser temperature. Units with WSE, ifeconomizing and mechanical cooling is necessary theeconomize valve will sacrifice free cooling andmodulate to maintain condensing saturated

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84 SCXG-SVX01P-EN

temperature. If not economizing, the condenser valvewill modulate to maintain condensing saturatedtemperature. Water-cooled units without head pressurecontrol will lock out mechanical cooling at enteringcondenser water temperatures below 54°F. Mechanicalcooling will resume when the entering condenserwater temperature exceeds 58°F.

Low Ambient Control (Air-Cooled UnitsOnly)The low ambient modulating output on the compressormodule is functional on all units with or without thelow ambient option. When the compressor modulestages up to it's highest stages 2 or 3 depending onunit size), the modulating output is 100% (10 Vdc).When the control is at stage 1, the modulating output(0-10 Vdc) controls the saturated condensingtemperature to within the programmable condensingtemperature low ambient control point.

Low Ambient Compressor LockoutUtilizes an analog input device. When the system isconfigured for low ambient compressor lockout, thecompressors are not allowed to operate if thetemperature of the outside air falls below the lockoutsetpoint. When the temperature rises 5°F above thelockout setpoint, the compressors are allowed tooperate. The factory preset is 50°F.

Return Air Temperature SensorThe return air temperature sensor is an analog inputdevice used with a return humidity sensor on units withthe comparative enthalpy option. The sensor monitorsthe return air temperature and compares it to theoutdoor temperature to establish which temperature isbest suited to maintain cooling requirements. It ismounted in the return air path and connected to theECEM.

Supply Fan Circuit Breaker, Fuses, andOverloadsThe supply fan motor is protected by either circuitbreakers fuses or a combination of fuses andoverloads, dependent upon unit configuration. Circuitbreakers are used on units without a VFD. They will tripand interrupt the motor power supply if the currentexceeds the breaker trip value. The RTM shuts allsystem functions off when detecting an open fanproving switch. Units with a VFD have fuses to protectthe VFD and motor. Units with a VFD w/bypass havefuses to protect VFD circuit and overloads to protect themotor when in bypass.

Supply Air Temperature Low LimitUses the supply air temperature sensor input tomodulate the economizer damper to minimum positionin the event the supply air temperature falls below theoccupied heating setpoint temperature.

Supply Air Temperature SensorThe supply air temperature sensor is an analog inputdevice. It monitors the supply air temperature forsupply air temperature control, supply air temperaturereset, supply air temperature low limiting, and supplyair tempering. It is mounted in the supply air dischargesection of the unit and connected to the RTM.

Supply Airflow Proving SwitchesThis is binary input device used on units to signal theRTM when the supply fan is operating. It is mounted inthe supply fan section and is connected to the RTM.During a request for fan operation and if the differentialswitch opens for 40 consecutive seconds, compressoroperation turns off, heat operation turns off, therequest for supply fan operation turns off and locks out,economizer damper option closes, and a manual resetdiagnostic initiates.

Low Entering Air Protection Device(LEATPD)The low entering air protection device (LEATPD) is abinary input on units with hydronic heat or a watersideeconomizer. It is optional on water-cooled units.

If the LEATPD is on a unit with factory-installed heat, itis mounted in the heat section and connected to theheat module. If the entering air temperature to theheating coil falls to 40°F, the normally open contacts onthe LEATPD close and cause the following events:

• The hydronic heat actuator fully opens.

• The supply fan turns off

• The outside air damper closes

• The SERVICE light at the remote zone sensor optionturns on.

• A LEATPD diagnostic displays at the humaninterface panel.

If the LEATPD is on a water-cooled unit without factory-installed heat, it is wired to the WSM. It will trip if theentering water temperature falls to 34°F, open theeconomizer valve, and energize the pump output.

High Duct Temp Thermostat Option OnUnits with a LCI-IThe high duct temperature thermostats are binaryinput devices used on units with a Tranecommunication interface module (TCI).They provide ahigh limit unit shutdown and require a manual reset.The thermostats are factory set to open if the supply airtemperature reaches 240°F, or the return airtemperature reaches 135°F. Once tripped, thethermostat requires a manual reset. Reset by pressingthe sensor’s reset button when the air temperaturedecreases approximately 25°F below the cutout point.

Filter SwitchA binary input device that measures the pressuredifferential across the unit filters. It is mounted in the

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SCXG-SVX01P-EN 85

filter section and is connected to the RTM. A diagnosticSERVICE signal is sent to the remote panel if thepressure differential across the filters is at least 0.5" w.c. The contacts will automatically open when thepressure differential across the filters decrease to 0.4"w.c. The switch differential can be field adjustedbetween 0.17" w.c. to 5.0" w.c. ± 0.05" w.c.

High Duct Static Switch OptionThe high duct static switch is field-mounted in theductwork or plenums with smoke dampers. It willcause a manual reset diagnostic if the duct staticexceeds the pre-set static limit. The static limit isadjustable at the HI.

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Pre-StartupPre-Startup ChecklistComplete this checklist after installing unit to verify allrecommended installation procedures are completebefore startup. This does not replace the detailedinstructions in the appropriate sections of this manual.Always read the entire section carefully to becomefamiliar with the procedures.

Supply Fan• Verify the fan and motor shafts are parallel.

• Verify the fan and motor sheaves are aligned.

• Check the fan belt condition and tension. Adjust thetension if belts are floppy or squeal continually.Replace worn or fraying belts in matched sets.

• Ensure the fan rotates freely.

• Tighten locking screws, bearing set screws andsheaves.

• Ensure bearing locking collars do not wobble whenrotated.

• Remove fan assembly tie down bolts.

• Ensure fan rotation is in direction of arrow on fanhousing. If incorrect, verify incoming powerphasing is correct. Switch wires on the fan contactto properly phase fan if necessary.

Ductwork• Ensure trunk ductwork to VAV boxes is complete

and secure to prevent leaks.

• Verify that all ductwork conforms to NFPA 90A or90B and all applicable local codes

Water-Cooled Unit Piping• Verify condensate drain, water piping drain plugs,

economizer header, and condenser vent plug areinstalled.

Air-Cooled Units Only• Verify leak test was performed after refrigerant

piping was installed.

• Verify liquid line filter driers installed.

Units with Hydronic Heat• Verify the entering water temperature sensor is

installed upstream of the hydronic coil.

Units with Electric Heat• Verify that a zone temp sensor is installed.

Electrical• Verify electrical connections are tight.

Components• Verify liquid line service valve, and suction and

discharge service valves if present, are open atstartup.

NNoottee:: Each compressor suction line contains a lowpressure sensor that will shut thecompressor down in low pressure situations.See Table 38, p. 69.

• Ensure system components are properly set andinstalled.

SCXG-SVX01P-EN 87

StartupWWAARRNNIINNGG

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To start the unit, complete the following steps in order.

Review Table 22, p. 40, if applicable. Confirm all stepswere completed.

Air-Cooled Only• Charging is more accurate at higher outdoor

temperatures. If outdoor temperature is < 80°F,temporarily disable fan pressure control switches.See unit wiring diagrams and disconnect the wiresbetween switches and terminal strip.

• Do not attempt to charge system with low ambientdampers operating (if applicable). Disable thesedampers in “Open” position before proceeding.

• Evaporator load should be at least 70°F return air,350 CFM/ton.

• Work on only one circuit at a time. See section“General Data,” p. 13 for compressor sequencing.

NNoottee:: R-410A compressors have belly band crankcaseheaters that must be energized 24 hours beforestarting compressor. Power to the unit willenergize the heaters. Heaters will be energizedduring the off-cycle as long as the unit has power.Failure to perform these pre-start instructionscould result in compressor damage.

1. Verify compressor crank case heaters have been onfor at least 24 hours.

2. Make sure all service valves are open.

3. Attach a thermocouple type temperature sensor onliquid line close to liquid line service valve. Toensure an accurate reading, clean line where sensoris attached. After securing sensor to line, insulatesensor and line to isolate it from ambient air.

4. Attach service gauges to suction and dischargeports.

5. Check low side pressure. Low pressure cutoutopens below, and closes above, values in Table 38,p. 69. If the low side pressure is less than the openpsig, refrigerant may need to be added to thesuction line before starting the compressor(s) toclose the switch. SLOWLY meter into the suctionline only as much R- 410A as needed to close thelow pressure cutout. Use the VAPOR chargingconnection. If possible, plan to use this entirerefrigerant bottle on the same unit in order tominimize fractionalization. Use an accurate scale tomeasure and record amount of R-410A added.

6. Switch the field supplied unit disconnect to “OFF”.Open the unit control box and plug in the resetrelay for only the circuit being started

WWAARRNNIINNGGHHaazzaarrddoouuss VVoollttaaggee!!FFaaiilluurree ttoo ddiissccoonnnneecctt ppoowweerr bbeeffoorree sseerrvviicciinngg ccoouullddrreessuulltt iinn ddeeaatthh oorr sseerriioouuss iinnjjuurryy..DDiissccoonnnneecctt aallll eelleeccttrriicc ppoowweerr,, iinncclluuddiinngg rreemmootteeddiissccoonnnneeccttss bbeeffoorree sseerrvviicciinngg.. FFoollllooww pprrooppeerrlloocckkoouutt//ttaaggoouutt pprroocceedduurreess ttoo eennssuurree tthhee ppoowweerrccaann nnoott bbee iinnaaddvveerrtteennttllyy eenneerrggiizzeedd.. VVeerriiffyy tthhaatt nnooppoowweerr iiss pprreesseenntt wwiitthh aa vvoollttmmeetteerr..

7. Turn 115 volt control circuit switch “ON”. Closecontrol box and switch field supplied unitdisconnect “ON”. Unit power should be off nolonger than 60 minutes to prevent refrigerantmigration to compressor sumps. If power is off forlonger than 60 minutes, allow time for crankcaseheaters to drive refrigerant from compressor sumpsbefore starting compressors.

8. Adjust setpoints at the HI.

88 SCXG-SVX01P-EN

NNoottee:: Sufficient cooling load must be visible torefrigerant circuit controls for mechanicalrefrigeration to operate. If necessary,temporarily reduce the discharge air setpointto verify the refrigeration cycle operation.

9. Check voltage at all compressor terminals to ensureit is within 10% of nameplate voltage.

10. Check voltage imbalance from these three voltagereadings at each compressor. Maximum allowablevoltage imbalance, phase to phase is 2%.

11. Start the first step compressor only.

12. Check amp draw at compressor terminals. RLA andLRA are on the unit nameplate.

13. Measure amp draw at evaporator fan motorterminals. FLA data is on the motor nameplate.

14. As soon as a compressor starts, verify correctrotation. If a scroll compressor is allowed to runbackwards for even a very short period of time,internal compressor damage could occur andcompressor life could be reduced. When rotatingbackwards scroll compressors make a loud noise,do not pump, and draw about 1/2 expected amps,and low side shell gets hot. Immediately shut off acompressor rotating backwards and correct wiring.

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15. AAiirr CCoooolleedd OOnnllyy: Check condenser fans for properrotation. From top of unit, correct rotation directionis clockwise. If running backwards, correct wiring.

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16. After 10 minutes, start second compressor ofmanifold circuits.

17. Allow 10 minutes for circuit operation to stabilize atfull load.

18. Complete charging, if required.

Final Refrigerant ChargeIf full charge was not used during installation, followthese steps:

1. Determine remaining charge required bysubtracting charge added during “PreliminaryRefrigerant Charging,” p. 40 from the total.

2. With all circuit compressors running, SLOWLYmeter remaining R-410A into the suction line fromthe LIQUID charging connection.

NNOOTTIICCEECCoommpprreessssoorr DDaammaaggee!!OOvveerrcchhaarrggiinngg ssyysstteemm ccoouulldd rreessuulltt iinn ccoommpprreessssoorrffaaiilluurree aanndd//oorr rreedduucceedd ccoommpprreessssoorr lliiffee..DDoo nnoott oovveerrcchhaarrggee ssyysstteemm.. EExxcceessssiivvee rreeffrriiggeerraannttcchhaarrggiinngg ccaann ccaauussee ccoommpprreessssoorr lliiqquuiidd sslluuggggiinngg aattssttaarrttuupp,, aanndd ccoonnddiittiioonnss wwhheerree ccoommpprreessssoorrss aanndd//oorrccoonnddeennsseerr ffaannss sshhoorrtt ccyyccllee..

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3. Use an accurate scale to measure and recordamount of R-410A added.

4. After unit has been operating for approximately 30minutes at full load, measure and record operatingpressures.

AAiirr CCoooolleedd OOnnllyy: Operating pressure measurementmust be made with all condenser fans running.

5. Repeat for other circuits.

6. Confirm, and adjust charge if needed, by checkingsubooling at AHRI 340/360 full load operatingconditions (80/67°F entering evap, ~300CFM/ton, 85/95°F EWT/LWT for water-cooled and 95°F OA forair-cooled).

• Water-cooled subcooling should be 8-10°F

• Air-cooled subcooling should be 14-18°F

SSttaarrttuupp

SCXG-SVX01P-EN 89

Startup ProcedureUsing the startup log on the following pages, establishnominal conditions for consistent measurements asfollows:

• Leaving air greater than 60°F

• Entering air temperature = 70 to 90°F

• Entering water temperature > 60°F

With all compressors running at full load:

1. Compute superheat from the suction line pressureand temperature at the compressor on each circuit.Adjust the thermal expansion valve settings ifnecessary. Superheat should be between 14 and20°F.

2. Inspect refrigerant flow in the liquid line sight glass.Flow should be smooth and even, with no bubblesonce the system has stabilized.

NNoottee:: Sight glass moisture indicator may showcaution or wet at startup. May need up to 12hours of operation for system to reachequilibrium and correctly showmoisture.

Normal startup will occur provided that Tracer™Summit is not controlling the module outputs or thegeneric BAS is not keeping the unit off. To preventTracer Summit from affecting unit operation, removeTracer wiring and make required changes to setpointand sensor sources.

Operating & Programming InstructionsSee Self-Contained Programming Guide, PKG-SVP01*-EN, for available unit operating setpoints andinstructions. A copy ships with each unit. For units withVFD option, see installer guide that ships with eachVFD.

Startup Log

Unit:

Unit Location:

Unit Voltage

Evaporator

Evaporator fanmotor horsepower:

Evaporator fanmotor amps:

Evaporator fan rpm (actual):

Evaporator system static (from test andbalance report or actual readings)

Supply duct static: Return duct static:

Evaporator system cfm (test and balancesheet or actual tested):

Evaporator Air Conditioners (with all compressor operating)

Entering Leaving

Dry-bulb °F: Dry-bulb °F:

Wet-bulb °F: Wet-bulb °F:

Circuit Compressor Amp Draw Suctionpressure,psig

Dischargepressure,psig

Superheat Liquid linepressure,psig

Sub cooling°F

A B(a)

Circuit A

Circuit B

Circuit C

Circuit D

Circuit E

Circuit F

(a) Air-Cooled only

SSttaarrttuupp

90 SCXG-SVX01P-EN

Water-Cooled Units

Circuit A Circuit B Circuit C Circuit D Circuit E Circuit F

Entering watertemp °F

Leaving watertemp °F

Entering waterpressure psig

Leaving waterpressure psig

Air-Cooled Units (Data taken from outside condensing unit)

Voltage

Amp Draw

Entering air temp °F (Outside condensingunit only)

Leaving air temp °F (Outside condensingunit only)

Refrigerant pressures at condenser, psig

Sub cooling at condenser °F

SSttaarrttuupp

SCXG-SVX01P-EN 91

MaintenanceService AccessRefer to the section, “,”, for recommended service andcode clearances. Access to thermostat unit controls isthrough a hinged access panel door on the front, lowerleft of the compressor section.

IntelliPak unit controls access is through a panel on themiddle right of the fan section. The panel is securedwith an automatic latch and quick-acting fasteners,which require a screwdriver to open.

Removable front unit panels provide access tocompressors, fan, motor and belts.

Removable left side panels give access to drive side,fan bearing, condensers, and waterside economizercontrol valve. The compressor, condenser and fanmotor access panels are secured with quick-actingfasteners. Access panels for evaporator coils,expansion and water valves, and left fan bearing aresheet metal screws. Access to other components forservice requires removal of panels secured with sheetmetal screws. During operation, sight glasses areviewable through portholes on the upper right sidepanel of the fan section.

Variable Frequency Drives are shipped separately andfield installed. Refer to the section “Variable FrequencyDrive Option (VFD),” p. 44, for VFD related dimensionsand weights.

Variable Frequency Drive (VFD)


The VFD access panel is hinged to allow service accessto the fan motor and belt drive components that arelocated behind it. To swing the panel open:

1. Remove the unit center cover panel to the left of theVFD panel.

2. Remove and discard the sheet metal shippingscrews along the top and bottom edges of the VFDpanel.

3. Disconnect the communications cable from thekeypad on the VFD door panel.

4. Turn the two slotted-head fasteners on the rightedge of the VFD panel fully counterclockwise.

5. Pull on the handle to swing the panel 180°.

To close and reattach the panel, reverse the procedureslisted above.

NNootteess::

• To secure the panel in the open positionduring service procedures, attach the chainmounted to the cabinet frame behind theunit center cover panel to the chain retainernotch on the edge of the VFD panel.

• Verify that all wires are in their properposition and not rubbing before replacingthe panel.

• Panel weight rating = 225 lbs. total,including factory-installed components.

Remote-Mounted Variable FrequencyDrive (VFD)Reference TR200 operating instructions (BAS-SVX19*-EN) for maintenance information on VFD.

Air FiltersWWAARRNNIINNGG


Filter access doors are on the unit’s left side. Filteraccess for the 2" filter rack on optional steam and hotwater coils and airside economizers is also on the leftside of the unit. To replace throwaway filters, remove

92 SCXG-SVX01P-EN

the dirty elements and install new filters with the filter’sdirectional arrows pointing toward the fan. Verify thatno air bypasses the filters.

Inspecting and Cleaning theDrain PanCheck the condensate drain pan and drain line toensure that the condensate drains properly at leastevery six months or as dictated by operatingexperience.

If evidence of standing water or condensate overflowexists, take steps to identify and remedy the causeimmediately. Refer to the troubleshooting section ofthis manual for possible causes and solutions.


Clean drain pans using the following procedure:

1. Disconnect all electrical power to the unit.

2. Don the appropriate personal protective equipment(PPE).

3. Remove all standing water.

4. Use a scraper or other tools to remove and solidmatter. Remove solid matter with a vacuum devicethat utilizes high efficiency particulate arrestance(HEPA) filters with a minimum efficiency of 99.97%at 0.3 micron particle size.

5. Thoroughly clean the contaminated area(s) with amild bleach and water solution or an EPA-approvedsanitizer specifically designed for HVAC use.Carefully follow the sanitizer manufacturer’sinstructions regarding product use.

6. Immediately rinse the drain pan thoroughly withfresh water to prevent potential corrosion from thecleaning solution.

7. Allow the unit to dry thoroughly before putting thesystem back into service.

8. Properly dispose of all contaminated materials andcleaning solution.

Inspecting and Cleaning the Fan


Inspect the fan section every six months or morefrequently if operating experience dictates. Cleanaccumulated dirt and organic matter on the fan interiorsurfaces using the following procedure:


2. Wear the appropriate personal protectiveequipment (PPE).

3. Use a portable vacuum with HEPA filtration toremove the loose dirt and organic matter. The filtershould be 99.97% efficient at 0.3 micron particlesize.

4. Thoroughly clean the fan and associatedcomponents with an industrial cleaning solution.Carefully follow the cleaning solutionmanufacturer’s instructions regarding personalprotection and ventilation when using theirproduct.

5. Rinse the affected surfaces thoroughly with freshwater and a fresh sponge to prevent potentialcorrosion of metal surfaces.

6. Allow the unit to dry completely before putting itback into service.

7. Properly dispose of all contaminated materials andcleaning solution.

MMaaiinntteennaannccee

SCXG-SVX01P-EN 93

Supply FanFan Drive


Perform the following procedures according to the“Maintenance Periodic Check List”:

1. Rotate the fan wheel to ensure it turns freely in theproper direction and is not rubbing on the fanhousing or inlet. If necessary, center the fan wheelagain.

2. Check the position of both shafts. Fan and motorshafts should operate parallel to each other formaximum belt and bearing life. Shim as necessaryunder the motor or fan bearings to obtain properalignment.

3. Check the fan motor sheave alignment with straightedge or a tightly pulled string. For sheaves ofdifferent widths, place a string in the center grooveof each sheave and pull it tight for a center line. SeeFigure 62, p. 95 for recommended torques.

4. Once the sheaves are properly aligned, tightensheave set screws to proper torque.

5. Check belt tension. Refer to the “Measuring BeltTension” section.

6. If required, adjust belt to the minimumrecommended tension. Refer to “Adjusting BeltTension” section.

7. Re-tighten bearing set screws to the proper torquesafter aligning the sheaves. See Table 52, p. 94 forproper torques.

8. Check the fan bearing locking collars for tightnesson the shaft. To tighten the locking collar, loosenthe set screw and slide the collar into its properposition over the extended end of the inner case.Tighten the set screw to the torque value in Table52, p. 94.

9. During air balancing, verify the sheave alignment,belt tension, and that the shaft is parallel.

Figure 61. Fan shaft and motor sheave alignment

Fan BearingsThe opposite drive end bearing is a special bearingwith close tolerance fit of balls and races. Replace thisbearing with the same part number as the originalbearing.

Follow the fan bearing lubrication schedules in Table47, p. 93, Table 48, p. 94, and Table 49, p. 94 toreference compatible fan bearing grease for specificbearings.

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Table 47. Baldor fan bearing lubrication schedule

Baldor Rated Speed, rpm

NEMA/ (IEC)Frame Size 3600 1800 1200 900

up to 210 incl.(132) 5500 hrs 12,000

hrs18,000hrs

22,000hrs

over 210 to 280incl. (180) 3600 hrs 9500 hrs 15,000

hrs18,000hrs

over 360 to 5800incl. (300) 2200 hrs 3500 hrs 7400 hrs 10,500

hrs


94 SCXG-SVX01P-EN

Table 48. AO smith bearing lubrication schedule

SpeedServiceOver1800rpm

FrameAll

Stand-ard

Service6

months

SevereService3

months

Extreme3

months

1800 rpm 140-180 3 yrs 1 yr 6 mths

210-280 2 1/2 yrs 10 1/2mths

5 1/2mths

320-360 2 yrs 9 mths 4 1/2mths

400-440 1 1/2 yrs 8 mths 4 mths

Note: Service standard - 8 hrs/day, normal to light loading, 100°Fambient temp. max. Severe service - 24 hrs/day, shockloading, vibration, dirt or dust, 100°F to 150°F ambienttemp. Extreme service - heavy shock or vibration, dirt ordust, 100°F to 150°F ambient temp.

Table 49. Compatible with NLGI grade 2 lithium fanbearing greases

Type

Shell Alvania EP2

Mobile SHC 220

FINA LICAL

Table 50. Compatible with NLGI grade 2 lithium fanbearing greases

Recommended Grease Recommended OperatingRange

FINA LICALShell Alvania EP2Mobile SHC 220

20°F to 205°F

Fan Belt TensionNNoottee:: Check fan belt tension at least twice during the

first days of new belt operation since there is arapid decrease in tension until belts are run-in.

Proper belt tension is necessary to endure maximumbearing and drive component life and is based on fanbrake horsepower requirements. If frayed or worn,replace belts in matched sets.

Measuring Belt TensionMeasure fan belt tension with a Browning, Gates, orequivalent belt tension gauge. Determine deflection bydividing the belt span distance (in inches) by 64. SeeFigure 62, p. 95. Use the following procedure tomeasure belt tension:

1. Measure belt span between centers of sheaves andset the large “O” ring of the tensioning gauge at 1/64 inch for each inch of belt span.

2. Set the load “O” ring at zero.

3. Place the large end of the gauge at the center of the

belt span. Press down until the large “O” ring iseven with the top of the belt line or the next belt asin Figure 62, p. 95. Place a straight edge across thesheaves as a reference point. See Figure 61, p. 93.

4. Remove the gauge. Note that the load “O” ring nowindicates a number on the plunger scale. Thisnumber represents pounds of force required todeflect the belt.

5. Check the reading from step 4 against the valuesgiven in Table 51, p. 94. If necessary, readjust belttension.

Table 51. Fan shaft bearing torques

SetscrewSize

Hex-SizeAcross Flats

Recommended Torque

In-lb ft-lb

1/4"-20 1/8” 180 15

5-16"-18 5-32” 402 33.5

Table 52. Fan hub and sheave torques

Unit Size Fan Dia.SetscrewSize

Torque (ft-lbs)

SCWG 20 8” (qty 2) 5/16” 12

SCWG 25 9” (qty 2) 5/16” 12

SCWG 30

11” (qty 2) 5/16” 12SCWG 35

SCRG 32

Adjusting Belt Tension

NNOOTTIICCEEBBeelltt TTeennssiioonn!!DDoo nnoott oovveerr--tteennssiioonn bbeellttss aass iitt ccoouulldd rreedduuccee ffaannaanndd mmoottoorr bbeeaarriinngg lliiffee,, aacccceelleerraattee bbeelltt wweeaarr aannddppoossssiibbllyy ccaauussee sshhaafftt ffaaiilluurree..


SCXG-SVX01P-EN 95

Figure 62. Belt tension gauge (top) and fan beltadjustment (bottom)

To adjust belt tension see Figure 62, p. 95 and performthe following procedure:

1. Loosen bolts A, B, and E on both sides of the slidingmotor base. See Figure 63, p. 96.

2. Loosen nuts C and D (as required for motorhorsepower) to slide the motor on its mountingplate in the proper direction to tension or relievetension on the belt.

3. Adjust nuts A-D and bolt E. Do not stretch the beltsover the sheaves.

4. Retighten all nuts and bolts.

5. Verify tension is adjusted properly.

Recommended belt tension range values are on theunit fan scroll. To access the fan scroll, face the right-hand side of the unit and remove the top left panel. Thebelt tension label is on the top right-hand corner of thefan scroll. See Figure 63, p. 96 and .

The correct operation tension for a V-belt drive is thelowest tension at which the belt will not slip under thepeak load conditions. It may be necessary to increasethe tension of some drives to reduce flopping orexcessive startup squealing.


96 SCXG-SVX01P-EN

Figure 63. Location of fan belt label on fan scroll (top) and belt tensioning with fan adjustment points (bottom)

Figure 64. Fan assembly


SCXG-SVX01P-EN 97

Refrigerant SystemIf refrigerant system repair is required, Leak Test,Brazing and Evacuation Procedures are described.

Preliminary charging is described in the Installation–Mechanical section, “Preliminary RefrigerantCharging,” p. 40 and final charging is described in theStartup section, “Final Refrigerant Charge,” p. 88.

Ignore Air Cooled Only steps for Water Cooledsystems.

Refrigerant systems that have been opened must havefilter driers replaced and complete leak test andevacuation before recharging.

Refrigerant Leak Test Procedure

WWAARRNNIINNGGCCoonnffiinneedd SSppaaccee HHaazzaarrddss!!FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonnss bbeellooww ccoouulldd rreessuulltt iinnddeeaatthh oorr sseerriioouuss iinnjjuurryy..DDoo nnoott wwoorrkk iinn ccoonnffiinneedd ssppaacceess wwhheerree rreeffrriiggeerraannttoorr ootthheerr hhaazzaarrddoouuss,, ttooxxiicc oorr ffllaammmmaabbllee ggaass mmaayy bbeelleeaakkiinngg.. RReeffrriiggeerraanntt oorr ootthheerr ggaasseess ccoouulldd ddiissppllaacceeaavvaaiillaabbllee ooxxyyggeenn ttoo bbrreeaatthhee,, ccaauussiinngg ppoossssiibblleeaasspphhyyxxiiaattiioonn oorr ootthheerr sseerriioouuss hheeaalltthh rriisskkss.. SSoommeeggaasseess mmaayy bbee ffllaammmmaabbllee aanndd oorr eexxpplloossiivvee.. IIff aa lleeaakkiinn ssuucchh ssppaacceess iiss ddeetteecctteedd,, eevvaaccuuaattee tthhee aarreeaaiimmmmeeddiiaatteellyy aanndd ccoonnttaacctt tthhee pprrooppeerr rreessccuuee oorrrreessppoonnssee aauutthhoorriittyy..

WWAARRNNIINNGGEExxpplloossiioonn HHaazzaarrdd!!FFaaiilluurree ttoo ffoollllooww ssaaffee lleeaakk tteesstt pprroocceedduurreess bbeelloowwccoouulldd rreessuulltt iinn ddeeaatthh oorr sseerriioouuss iinnjjuurryy oorreeqquuiippmmeenntt oorr pprrooppeerrttyy--oonnllyy--ddaammaaggee..NNeevveerr uussee aann ooppeenn ffllaammee ttoo ddeetteecctt ggaass lleeaakkss.. UUssee aalleeaakk tteesstt ssoolluuttiioonn ffoorr lleeaakk tteessttiinngg..

WWAARRNNIINNGGEExxpplloossiioonn HHaazzaarrdd!!FFaaiilluurree ttoo ffoollllooww tthheessee iinnssttrruuccttiioonnss ccoouulldd rreessuulltt iinnddeeaatthh oorr sseerriioouuss iinnjjuurryy oorr eeqquuiippmmeenntt oorr pprrooppeerrttyy--oonnllyy ddaammaaggee..UUssee oonnllyy ddrryy nniittrrooggeenn wwiitthh aa pprreessssuurree rreegguullaattoorr ffoorrpprreessssuurriizziinngg uunniitt.. DDoo nnoott uussee aacceettyylleennee,, ooxxyyggeenn oorrccoommpprreesssseedd aaiirr oorr mmiixxttuurreess ccoonnttaaiinniinngg tthheemm ffoorrpprreessssuurree tteessttiinngg.. DDoo nnoott uussee mmiixxttuurreess ooff aahhyyddrrooggeenn ccoonnttaaiinniinngg rreeffrriiggeerraanntt aanndd aaiirr aabboovveeaattmmoosspphheerriicc pprreessssuurree ffoorr pprreessssuurree tteessttiinngg aass tthheeyymmaayy bbeeccoommee ffllaammmmaabbllee aanndd ccoouulldd rreessuulltt iinn aanneexxpplloossiioonn.. RReeffrriiggeerraanntt,, wwhheenn uusseedd aass aa ttrraaccee ggaasssshhoouulldd oonnllyy bbee mmiixxeedd wwiitthh ddrryy nniittrrooggeenn ffoorrpprreessssuurriizziinngg uunniittss..

WWAARRNNIINNGGEExxpplloossiioonn HHaazzaarrdd!!FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonn bbeellooww ccoouulldd rreessuulltt iinnddeeaatthh oorr sseerriioouuss iinnjjuurryy..DDoo nnoott eexxcceeeedd uunniitt nnaammeeppllaattee ddeessiiggnn pprreessssuurreesswwhheenn lleeaakk tteessttiinngg ssyysstteemm..

WWAARRNNIINNGGRR--441100AA RReeffrriiggeerraanntt uunnddeerr HHiigghheerrPPrreessssuurree tthhaann RR--2222!!FFaaiilluurree ttoo uussee pprrooppeerr eeqquuiippmmeenntt oorr ccoommppoonneennttss aassddeessccrriibbeedd bbeellooww,, ccoouulldd rreessuulltt iinn eeqquuiippmmeenntt ffaaiilliinnggaanndd ppoossssiibbllyy eexxppllooddiinngg,, wwhhiicchh ccoouulldd rreessuulltt iinnddeeaatthh,, sseerriioouuss iinnjjuurryy,, oorr eeqquuiippmmeenntt ddaammaaggee..TThhee uunniittss ddeessccrriibbeedd iinn tthhiiss mmaannuuaall uussee RR--441100AArreeffrriiggeerraanntt wwhhiicchh ooppeerraatteess aatt hhiigghheerr pprreessssuurreesstthhaann RR--2222.. UUssee OONNLLYY RR--441100AA rraatteedd sseerrvviicceeeeqquuiippmmeenntt oorr ccoommppoonneennttss wwiitthh tthheessee uunniittss.. FFoorrssppeecciiffiicc hhaannddlliinngg ccoonncceerrnnss wwiitthh RR--441100AA,, pplleeaasseeccoonnttaacctt yyoouurr llooccaall TTrraannee rreepprreesseennttaattiivvee..

NNoottee:: These service procedures require working withrefrigerant. Do not release refrigerant to theatmosphere! The service technician mustcomply with all federal, state, and local laws.

When leak-testing refrigerant systems, observe allsafety precautions. Leak test only one circuit at a timeto minimize system exposure to potentially harmfulmoisture in the air.

Field Piping (Air-cooled Discharge and LiquidLines)1. Ensure all required field-installed piping pressure

tests are completed in accordance with nationaland/or local codes.

2. Close liquid line angle valve.

3. Connect R-410A refrigerant cylinder to high sidecharging port (at Remote Condenser or field-supplied discharge line access port). Addrefrigerant to reach pressure of 12 to 15 psig.

4. Disconnect refrigerant cylinder. Connect drynitrogen cylinder to high side charging port andincrease pressure to 150 psig. Do not exceed highside (discharge) unit nameplate design pressure.Do not subject low side (suction) components tohigh side pressure.

5. Check all piping joints, valves, etc. for leaks.Recommend using electronic detector capable ofmeasuring 0.1 oz/year leak rate.

6. If a leak is located, use proper procedures toremove the refrigerant/nitrogen mixture, breakconnections and make repairs. Retest for leaks.



98 SCXG-SVX01P-EN

System Repair1. If system is water cooled with service valves, or air

cooled, high and low side may be testedindependently by closing liquid line angle valve andwater cooled unit discharge line ball valve.Otherwise leave all valves open and DO NOTexceed low side design pressure.

2. Connect R-410A refrigerant cylinder to chargingport, add refrigerant to reach pressure of 12 to 15psig.

3. Disconnect refrigerant cylinder. Connect drynitrogen cylinder to high side charging port andincrease pressure to 150 psig. DO NOT exceed unitnameplate design pressures. If testing completesystem, low side design pressure is maximum.

4. Check piping and/or components as appropriate forleaks.

5. Recommend using electronic detector capable ofmeasuring 0.1 oz/year leak rate.

6. If a leak is located, use proper procedures toremove the refrigerant/nitrogen mixture, breakconnections and make repairs. Retest for leaks.


Brazing Procedures

WWAARRNNIINNGGEExxpplloossiioonn HHaazzaarrdd aanndd DDeeaaddllyy GGaasseess!!FFaaiilluurree ttoo ffoollllooww aallll pprrooppeerr ssaaffee rreeffrriiggeerraanntthhaannddlliinngg pprraaccttiicceess ccoouulldd rreessuulltt iinn ddeeaatthh oorr sseerriioouussiinnjjuurryy..NNeevveerr ssoollddeerr,, bbrraazzee oorr wweelldd oonn rreeffrriiggeerraanntt lliinneess oorraannyy uunniitt ccoommppoonneennttss tthhaatt aarree aabboovvee aattmmoosspphheerriiccpprreessssuurree oorr wwhheerree rreeffrriiggeerraanntt mmaayy bbee pprreesseenntt..AAllwwaayyss rreemmoovvee rreeffrriiggeerraanntt bbyy ffoolllloowwiinngg tthheegguuiiddeelliinneess eessttaabblliisshheedd bbyy tthhee EEPPAA FFeeddeerraall CClleeaannAAiirr AAcctt oorr ootthheerr ssttaattee oorr llooccaall ccooddeess aass aapppprroopprriiaattee..AAfftteerr rreeffrriiggeerraanntt rreemmoovvaall,, uussee ddrryy nniittrrooggeenn ttoobbrriinngg ssyysstteemm bbaacckk ttoo aattmmoosspphheerriicc pprreessssuurree bbeeffoorreeooppeenniinngg ssyysstteemm ffoorr rreeppaaiirrss.. MMiixxttuurreess ooffrreeffrriiggeerraannttss aanndd aaiirr uunnddeerr pprreessssuurree mmaayy bbeeccoommeeccoommbbuussttiibbllee iinn tthhee pprreesseennccee ooff aann iiggnniittiioonn ssoouurrcceelleeaaddiinngg ttoo aann eexxpplloossiioonn.. EExxcceessssiivvee hheeaatt ffrroommssoollddeerriinngg,, bbrraazziinngg oorr wweellddiinngg wwiitthh rreeffrriiggeerraannttvvaappoorrss pprreesseenntt ccaann ffoorrmm hhiigghhllyy ttooxxiicc ggaasseess aannddeexxttrreemmeellyy ccoorrrroossiivvee aacciiddss..

Proper brazing techniques are essential when installingrefrigerant piping. The following factors should be keptin mind when forming sweat connections:

1. When heating copper in the presence of air, copperoxide forms. To prevent copper oxide from forminginside the tubing during brazing, sweep an inertgas, such as dry nitrogen, through the tubing. Anitrogen flow of 1 to 3 cubic feet per minute issufficient to displace the air in the tubing andprevent oxidation of the interior surfaces. Use a

pressure regulating valve or flow meter to controlthe flow.

2. Ensure that the tubing surfaces requiring brazingare clean, and that the tube ends are carefullyreamed to remove any burrs.

3. Make sure the inner and outer tubes of the joint aresymmetrical and have a close clearance, providingan easy “slip” fit. If the joint is too loose, theconnection’s tensile strength is significantlyreduced. Ensure the overlap distance is equal to theinner tube diameter.

4. Wrap each refrigerant line component with a wetcloth to keep it cool during brazing. Excessive heatcan damage the internal components.

NNoottee:: Use 40-45% silver brazing alloy (BAg-7 orBAg-28) on dissimilar metals. Use BCup-6brazing alloy on copper-to-copper joints.

5. If using flux, apply it sparingly to the joint. Excessflux will contaminate the refrigerant system.

6. Apply heat evenly over the length andcircumference of the joint.

7. Begin brazing when the joint is hot enough to meltthe brazing rod. The hot copper tubing, not theflame, should melt the rod.

8. Continue to apply heat evenly around the jointcircumference until the brazing material is drawninto the joint by capillary action, making amechanically sound and gas-tight connection.

9. Visually inspect the connection after brazing tolocate any pinholes or crevices in the joint. Use amirror if joint locations are difficult to see.

System Evacuation Procedures• Each refrigeration circuit must be evacuated before

the unit can be charged and started.

• Use a rotary type vacuum pump capable of pullinga vacuum of 100 microns or less.

• Verify that the unit disconnect switch and thesystem control circuit switches are “OFF”.

• Oil in the vacuum pump should be changed eachtime the pump is used with high quality vacuumpump oil. Before using any oil, check the oilcontainer for discoloration, which usually indicatesmoisture in the oil and/or water droplets. Moisturein the oil adds to what the pump has to removefrom the system, making the pump inefficient.

• When connecting vacuum pump to refrigerationsystem, it is important to manifold vacuum pump toboth high and low side of system (liquid line accessvalve and suction line access valve). Follow pumpmanufacturer’s directions for proper methods ofusing vacuum pump.

• Lines used to connect the pump to the systemshould be copper and of the largest diameter thatcan practically be used. Using larger line sizes with


SCXG-SVX01P-EN 99

minimum flow resistance can significantly reduceevacuation time.

NNoottee::

• Rubber or synthetic hoses are not recommendedfor system evacuation. They have moistureabsorbing characteristics that result in excessiverates of evaporation, causing pressure rise duringstanding vacuum test. This makes it impossible todetermine if system has a leak, excessive residualmoisture, or continual or high rate of pressureincrease due to hoses.

• Install an electronic micron vacuum gauge in thecommon line ahead of the vacuum pump shutoffvalve, as shown in Figure 65, p. 99. Close Valves Band C, and open Valve A.

Start vacuum pump. After several minutes the gaugereading will indicate the maximum vacuum thepump is capable of pulling. Rotary pumps shouldproduce vacuums of 100 microns or less.

NNOOTTIICCEEMMoottoorr WWiinnddiinngg DDaammaaggee!!FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonnss bbeellooww ccoouullddrreessuulltt iinn ccoommpprreessssoorr mmoottoorr wwiinnddiinngg ddaammaaggee..DDoo nnoott uussee aa mmeeggoohhmm mmeetteerr oorr aappppllyy vvoollttaaggeeggrreeaatteerr tthhaann 5500 VVDDCC ttoo aa ccoommpprreessssoorr mmoottoorrwwiinnddiinngg wwhhiillee iitt iiss uunnddeerr aa ddeeeepp vvaaccuuuumm..

• Open Valves B and C. Evacuate system to apressure of 300 microns or less. As vacuum is beingpulled on system, it may appear that no furthervacuum is being obtained, yet pressure is high. It isrecommended during evacuation process to“break” vacuum to facilitate evacuation.

• To break the vacuum, shut valves A, B, & C andconnect a refrigerant cylinder to charging port onmanifold. Purge air from hose. Raise standingvacuum pressure in system to “zero” (0 psig) gaugepressure. Repeat process two or three times duringevacuation.

NNoottee:: It is unlawful to release refrigerant into theatmosphere. When service proceduresrequire working with refrigerants, the servicetechnician must comply with all Federal,State, and local laws.

Standing Vacuum TestOnce 300 microns or less is obtained, close valve A andleave valves B and C open to allow the vacuum gaugeto read the actual system pressure. Let system equalizefor approximately 15 minutes. This is referred to as a“standing vacuum test” where time versus pressurerise. Maximum allowable rise over a 15 minute periodis 200 microns. If pressure rise is greater than 200microns but levels off to a constant value, excessivemoisture is present. If pressure steadily continues torise, a leak is indicated. Figure 66, p. 100 illustratesthree possible results of “standing vacuum test”.

If a leak is encountered, repair the system and repeatthe evacuation process until the recommendedvacuum is obtained. Once the system has beenevacuated, break the vacuum with refrigerant andcomplete the remaining Pre-Start procedures beforestarting the unit.

Figure 65. Typical vacuum pump hookup


100 SCXG-SVX01P-EN

Figure 66. Evacuation time vs. pressure rise

200

400

600

800

1000

1200

1400

1600

-10 0 10 20 30 40 50 60 70 80 90

Pres

sure

in M

icro

ns

Time in Minutes

Continously increasing pressureindicates the presence of leaks,moisture, or both.

Initial evacuation pressure.

State of equilibrium indicates thetrue amount of moisture left inthe system. It indicates that noleaks are present and the systemis properly evacuated.

State of equilibrium indicates thetrue amount of moisture left inthe system. It indicates that noleaks, but requires further evacuation.

CompressorsScroll Compressor Failure Diagnosis andReplacementIf compressor failure is suspected, refer to COM-SVN01for detailed information regarding compressor failurediagnosis and replacement of scroll compressors.


SCXG-SVX01P-EN 101

ComponentsFigure 67. Typical water-cooled compressor section components

NNoottee:: Tighten bolts to 38 ft. lbs.

IImmppoorrttaanntt:: On units ordered with a Design Special ofInlet Guide Vanes, refer to non-current IOM(SCXF-SVX01) dated on or before March2008 for maintenance procedure.


102 SCXG-SVX01P-EN

Cleaning Coil Fin

WWAARRNNIINNGGHHaazzaarrddoouuss CChheemmiiccaallss!!CCooiill cclleeaanniinngg aaggeennttss ccaann bbee eeiitthheerr aacciiddiicc oorr hhiigghhllyyaallkkaalliinnee aanndd ccaann bbuurrnn sseevveerreellyy iiff ccoonnttaacctt wwiitthh sskkiinnoorr eeyyeess ooccccuurrss..HHaannddllee cchheemmiiccaall ccaarreeffuullllyy aanndd aavvooiidd ccoonnttaacctt wwiitthhsskkiinn.. AALLWWAAYYSS wweeaarr PPeerrssoonnaall PPrrootteeccttiivveeEEqquuiippmmeenntt ((PPPPEE)) iinncclluuddiinngg ggoogggglleess oorr ffaaccee sshhiieelldd,,cchheemmiiccaall rreessiissttaanntt gglloovveess,, bboooottss,, aapprroonn oorr ssuuiitt aassrreeqquuiirreedd.. FFoorr ppeerrssoonnaall ssaaffeettyy rreeffeerr ttoo tthhee cclleeaanniinnggaaggeenntt mmaannuuffaaccttuurreerr’’ss MMaatteerriiaallss SSaaffeettyy DDaattaa SShheeeettaanndd ffoollllooww aallll rreeccoommmmeennddeedd ssaaffee hhaannddlliinnggpprraaccttiicceess..

WWAARRNNIINNGGHHaazzaarrddoouuss VVoollttaaggee ww//CCaappaacciittoorrss!!FFaaiilluurree ttoo ddiissccoonnnneecctt ppoowweerr aanndd ddiisscchhaarrggeeccaappaacciittoorrss bbeeffoorree sseerrvviicciinngg ccoouulldd rreessuulltt iinn ddeeaatthh oorrsseerriioouuss iinnjjuurryy..DDiissccoonnnneecctt aallll eelleeccttrriicc ppoowweerr,, iinncclluuddiinngg rreemmootteeddiissccoonnnneeccttss aanndd ddiisscchhaarrggee aallll mmoottoorr ssttaarrtt//rruunnccaappaacciittoorrss bbeeffoorree sseerrvviicciinngg.. FFoollllooww pprrooppeerrlloocckkoouutt// ttaaggoouutt pprroocceedduurreess ttoo eennssuurree tthhee ppoowweerrccaannnnoott bbee iinnaaddvveerrtteennttllyy eenneerrggiizzeedd.. VVeerriiffyy wwiitthh aaCCAATT IIIIII oorr IIVV vvoollttmmeetteerr rraatteedd ppeerr NNFFPPAA 7700EE tthhaatt aallllccaappaacciittoorrss hhaavvee ddiisscchhaarrggeedd..FFoorr aaddddiittiioonnaall iinnffoorrmmaattiioonn rreeggaarrddiinngg tthhee ssaaffeeddiisscchhaarrggee ooff ccaappaacciittoorrss,, sseeee PPRROODD--SSVVBB0066**--EENN..

NNOOTTIICCEECCooiill DDaammaaggee!!FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonnss bbeellooww ccoouulldd rreessuulltt iinnccooiill ddaammaaggee..DDoo nnoott cclleeaann tthhee rreeffrriiggeerraanntt ccooiill wwiitthh hhoott wwaatteerr oorrsstteeaamm aass iitt ccoouulldd ccaauussee hhiigghh pprreessssuurree iinnssiiddee tthheeccooiill ttuubbiinngg..DDoo nnoott uussee aacciiddiicc cchheemmiiccaall ccooiill cclleeaanneerrss.. AAllssoo,, ddoonnoott uussee aallkkaalliinnee cchheemmiiccaall ccooiill cclleeaanneerrss wwiitthh aa ppHHvvaalluuee ggrreeaatteerr tthheenn 88..55 ((aafftteerr mmiixxiinngg)) wwiitthhoouutt uussiinnggaann aalluummiinnuumm ccoorrrroossiioonn iinnhhiibbiittoorr iinn tthhee cclleeaanniinnggssoolluuttiioonn..

• Keep coils clean to maintain maximumperformance. For operation at its highest efficiency,clean the refrigerant coil often during periods ofhigh cooling demand or when dirty conditionsprevail. Clean the coil a minimum of once per yearto prevent dirt buildup in the coil fins, where it maynot be visible.

• Remove large debris from the coils and straightenfins before cleaning. Remove filters beforecleaning.

• Clean refrigerant coils with cold water anddetergent, or with one of the commercially

available chemical coil cleaners. Rinse coilsthoroughly after cleaning.

• Economizer and evaporator coils are installed sothe evaporator is directly behind the economizer.To clean between the coils, remove the sheet metalblock off. Access the block off by removing thecorner panels on the left or right rear side of theunit.

• If the refrigerant coil is installed back to back withthe waterside economizer coil, use a cleaner that isacceptable for cleaning both types of coils.

Inspecting and Cleaning CoilsCoils become externally fouled as a result of normaloperation. Coil surface dirt reduces heat transfer abilityand can cause comfort problems, increased airflowresistance and thus increased operating energy costs.

Inspect coils at least every six months or morefrequently as dictated by operating experience.Cleaning frequently is dependent upon systemoperating hours, filter maintenance, efficiency, and dirtload. Following is the suggested method for cleaningsteam and hot water coils.

Steam and Hot Water Coils



2. Wear appropriate personal protective equipment(PPE).

3. Access both sides of the coil section.

4. Use a soft brush to remove loose debris from bothsides of the coil.

5. Use a steam cleaning machine, starting from thetop of the coil and working downward. Clean theleaving air side of the coil first, then the entering airside. Use a block-off to prevent steam from blowingthrough the coil and into a dry section of the unit.

6. Repeat step 5 as necessary. Confirm that the drainline is open following completion of the cleaningprocess.

7. Allow the unit to dry thoroughly before putting the


SCXG-SVX01P-EN 103

system back into service.

8. Straighten any coil fins that may be damaged with afin rake.

9. Replace all panels and parts and restore electricalpower to the unit.

10. Ensure that contaminated material does not contactother areas of the equipment or building. Properlydispose of all contaminated materials and cleaningsolutions.

Refrigerant Coils



2. Wear the appropriate personal protectiveequipment (PPE).

3. Access to the coil section of the unit (both sides).


5. Mix a high quality coil cleaning detergent withwater according to the manufacturer’s instructions.If the detergent is strongly alkaline after mixing (pH8.5 or higher), it must contain an inhibitor. Carefullyfollow the cleaning solution manufacturer’sinstructions regarding product use.

6. Place the mixed solution in a garden pump-upsprayer or high pressure sprayer. If using a highpressure sprayer note the following:

• Maintain a minimum nozzle spray angle of 15°

• Spray perpendicular to the coil face

• Protect other areas of the equipment andinternal controls from contact with moisture orthe cleaning solution

• Keep the nozzle at least six inches from the coil

• Do not exceed 600 psig

Draining the Waterside Economizer Coil

NNOOTTIICCEECCooiill FFrreeeezzee--UUpp!!FFaaiilluurree ttoo ffoollllooww iinnssttrruuccttiioonn bbeellooww ccoouulldd rreessuulltt iinneeqquuiippmmeenntt ddaammaaggee..DDrraaiinn aanndd vveenntt ccooiillss wwhheenn nnoott iinn uussee.. TTrraanneerreeccoommmmeennddss ggllyyccooll pprrootteeccttiioonn iinn aallll ppoossssiibblleeffrreeeezziinngg aapppplliiccaattiioonnss.. UUssee aa ggllyyccooll aapppprroovveedd ffoorruussee wwiitthh ccoommmmeerrcciiaall ccoooolliinngg aanndd hheeaattiinngg ssyysstteemmssaanndd ccooppppeerr ttuubbee ccooiillss..

Drain plugs are in the piping below supply and returnheader for each coil. Use these plugs to drain the coiland piping. When draining the coil, open the vents atthe top of the supply and return headers. Also, a drainplug is at the bottom of the inlet condenser manifoldand in the outlet pipe near the left side of the unit.Remove these plugs to drain the condensers. Be sureto open the vent plugs at the top of the condenser inletand outlet manifold. See .

When refilling the condenser/waterside economizercoil system with water, provide adequate watertreatment to prevent the formation of scale orcorrosion.

Cleaning the Condenser


Condensing water contains minerals that collect on thecondenser tube walls. Cooling towers also collect dustand foreign materials that deposit in the condensertube. The formation of scale or sludge in the condenseris indicated by a decreased water flow, lowtemperature difference between inlet and outlet water,and abnormally high condensing temperatures. Tomaintain maximum condenser efficiency, thecondenser must remain free of built-up scale andsludge. Clean the condenser either mechanically orchemically.


2. Wear appropriate personal protective equipment(PPE).

3. Access both sides of the coil section.



104 SCXG-SVX01P-EN

5. Use a steam cleaning machine, starting from thetop of the coil and working downward. Clean theleaving air side of the coil first, then the entering airside. Use a block-off to prevent steam from blowingthrough the coil and into a dry section of the unit.

6. Repeat step 5 as necessary. Confirm that the drainline is open following completion of the cleaningprocess.

7. Allow the unit to dry thoroughly before putting thesystem back into service.

8. Straighten any coil fins that may be damaged with afin rake.

9. Replace all panels and parts and restore electricalpower to the unit.

10. Ensure that contaminated material does not contactother areas of the equipment or building. Properlydispose of all contaminated materials and cleaningsolutions.

Chemical Cleaning of Condenser andEconomizer CoilChemical cleaning removes scale deposits built up byminerals in the water. For a suitable chemical solution,consult a water treatment specialist. The condenserwater circuit is composed of copper, steel, and castiron. The chemical supply house should approve orprovide all materials used in the external circulatingsystem, along with the quantity of cleaning material,duration of cleaning time, and safety precautionsnecessary for handling the cleaning agent.

Piping ComponentsWater Valves


Water valves have a stern packing nut. If there is

evidence of water leakage at the valve stem, proceed asfollows:

1. Remove actuator motor from support plate.

2. Remove shaft coupling.

3. Torque the packing nut to 10-ft.-lbs. of torque.

4. Replace shaft coupling.

5. Replace actuator motor.

Flow SwitchFlow switches have a magnet on the vane assemblythat attracts ferrous particulate may build up on themagnet to the point that the vane will wedge and notoperate properly. When the flow switch does notoperate, remove and replace.

Maintenance Periodic ChecklistsWWAARRNNIINNGG

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Monthly ChecklistThe following check list provides the recommendedmaintenance schedule to keep the commercial self-contained equipment running efficiently.

1. Inspect unit air filters. Clean or replace if airflow isblocked or if filters are dirty.

2. Inspect coils for excess moisture or icing. Icing onthe coils may indicate low airflow supply, restrictedairflow from dirty fins, evaporator frost protectionsensor problems, or a shortage of refrigerantflowing through the coil.

3. Check that condensate from the evaporator andeconomizer coils flows freely through thecondensate piping, traps, drain pan, and drainageholes. Remove algae and or any airflowobstructions.


SCXG-SVX01P-EN 105

4. Check the condition and tension of fan belts. Adjusttension if belts are floppy or squeal continually.Replace worn or fraying belts in matched sets.

NNoottee:: Check belt tension and adjust it at least twicedaily the first days of new belt operation. Belttension will rapidly decrease until the beltsare run in.

5. Check the liquid line sight glasses during operation.Bubbles in the sight glasses indicate a possibleshortage of refrigerant or an obstruction in theliquid lines, e.g. dirty liquid line filter driers.

6. Inspect filter driers for leaks, flow obstructions, ortemperature drop across the filter drier. Anoticeable temperature differential, e.g. 5°F, in theliquid line may indicate an obstruction. Replace thefilter drier if it appears clogged.

7. Inspect the optional waterside economizer coil.Clean the coil to prevent airflow restrictionsthrough the fins.

8. Check and record operating pressures.

Semi-Annual Maintenance1. Verify the fan motor is properly lubricated. Follow

lubrication recommendations on the motor tag ornameplate. Contact the motor manufacturer formore information.

2. Lubricate fan bearings. For best results, lubricatebearings during unit operation. Refer to the “FanBearings” section for recommended grease.

NNoottee:: The bearings are manufactured using aspecial synthetic lithium-based greasedesigned for long life and minimum lubeintervals. Over lubrication can be just asharmful as not enough.

3. With power disconnected, manually rotate the fanwheel to check for obstructions in the housing or

interference with fan blades. Remove obstructionsand debris. Center the fan wheel if necessary.

4. Check the fan assembly sheave alignment. Tightenset screws to their proper torques.

5. Check water valves for leakage at valve stempacking nut.

NNoottee:: Perform this procedure monthly if the unit isin a coastal or corrosive environment.

Annual MaintenanceCheck and tighten all set screws, bolts, locking collarsand sheaves.

1. Inspect, clean, and tighten all electrical connections.

2. Visually inspect the entire unit casing for chips orcorrosion. Remove rust or corrosion and repaintsurfaces.

3. Visually check for leaks in refrigerant piping.

4. Inspect fan, motor, and control contacts. Replacebadly worn or eroded contacts.

5. Inspect the thermal expansion valve sensing bulbsfor cleanliness, good contact with the suction line,and adequate insulation from ambient air.

6. Verify the superheat setting is 12 -17°F at thecompressor.

When checking operating pressures and conditions,establish the following nominal conditions forconsistent measurements.

• Leaving air temperature greater than 60°F

• Entering air temperature is 80 - 90°F

• Entering water temperature greater than 65°F

• Compressors running at full load

• Drain the condensing water system and inspect itthoroughly for fouling; clean if necessary.


106 SCXG-SVX01P-EN

DiagnosticsTroubleshootingSystem Checks

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Before proceeding with technical trouble charts orcontrols checkout, complete the following systemanalysis:

1. Measure actual supply voltage at the compressorand an motor terminals with the unit running.Voltage must be within the range listed on themotor nameplate. Phase imbalance must be lessthan 2.0%.

2. Check all wiring and connections to be sure thatthey are intact, secure and properly routed. The aswired system diagrams are provided in the unitcontrol panel.

3. Check that all fuses are installed and properly sized.

4. Inspect air filters and coils to be sure that airflow tothe unit is not restricted.

5. Check the zone thermostat settings.

6. Ensure that the fan is rotating in the properdirection. If phasing is wrong at the main powerterminal block, the fan and compressors will notrun correctly.

7. Inspect ductwork and duct connections fortightness.

Operating ProceduresInstall pressure gauges on the discharge and suctionline access valves. When the unit has stabilized (afteroperating approximately 15 minutes at full load),

record suction and discharge pressures. Systemmalfunctions such as low airflow, line restrictions,incorrect refrigerant charge, malfunctioning ofexpansion valves, damaged compressors, etc. willresult in pressure variations which are outside thenormal range.

NNoottee:: If phasing at the main incoming power terminalis incorrect, switch two of the three incomingpower leads. If a compressor has been replacedand the phase is changed at the compressor, itwill run backwards and discharge pressure willbe very low. To resolve incorrect compressorwire phasing, change phasing at the compressor.

It is important that pressures be measured under stableand constant conditions in order for the readings to beuseful.

Voltage ImbalanceVoltage imbalance on three-phase systems can causemotor overheating and premature failure. Maximumallowable imbalance is 2.0%, and the readings used todetermine it must be measured at the compressorterminals.

Voltage imbalance is defined as 100 times the sum ofthe division of the three voltages from the averagevoltage. If, for example, the three measured voltagesare 221, 230, 227, the average is:

221 + 230 + 227

3= 226 volts

Therefore, the percentage of voltage imbalance is:

100*(226-221)/226 = 2.2%

In this example, 2.2% imbalance of more than 2.0%exists, be sure to check the voltage at the unitdisconnect and terminal block switch. If an imbalanceat the unit disconnect switch does not exceed 2.0%, theimbalance is caused by faulty wiring within the unit. Besure to conduct a thorough inspection of the unitelectrical wiring connections to locate the fault, andmake any repairs necessary.

Table 53. Potential unit issues and solutions

Problem Possible Cause Remedy

Drain pan is overflowing Plugged drain line Unit not level Clean drain line Level unit

Standing water in drain pan Unit not level Plugged drain line Level Unit Clean drain line

Wet interior insulation Coil face velocity too high Improper trapdesign Drain pan leaks/overflowing

Condensation on surfaces

Reduce fan speed Design trap per unitinstallation instructions Repair Leaks Insulate

surfaces

SCXG-SVX01P-EN 107

Table 53. Potential unit issues and solutions (continued)

Problem Possible Cause Remedy

Excess dirt in unit Missing filters Filter bypass Replace filters Reduce filter bypass

Microbial growth (mold) Standing water in drain pan See "Standing water in drain pan" above

Additional Diagnostic ResourcesRefer to the Self-Contained Programming Guide, PKG-SVP01, for specific unit programming andtroubleshooting information. In particular, reference

the “Service Mode Menu” and “Diagnostic Menu”sections in the programming guide. Refer to thefollowing text for general diagnostic andtroubleshooting procedures.

Category Diagnostic

AAuto Reset S/A Static Pressure Limit

Problem The supply air static pressure went too high. Reason for Diagnostic: The S/A static pressure exceeded the S/A static pressurelimit setpoint for at least one second continuously.

ControlsReaction

A “supply air pressure shutdown” signal is sent to the following functions:

• Compressor staging control

• Economizer actuator control

• Heat operation

• Supply fan control,

• VFD control

• Exhaust fan control

• Exhaust actuator control

ResetRequired

(PAR)The supply fan is not allowed to restart for 15 seconds after the diagnostic occurs. An auto reset will also occur if the unitcycles out of occupied mode and back.

CCO2 Sensor Failure

Problem The VCM CO2 sensor input signal is out of range.

Check Check field/unit wiring between sensor and VCM.

Reason forDiagnostic The unit is reading a signal that is out of range for the CO2 sensor transducer input.

ControlsReaction The CO2 reset function disables.

ResetRequired

(PAR) An automatic reset occurs after the CO2 sensor transducer input receives a signal that is within range for ten continuousseconds.

Compressor Contactor Fail—Circuit 1, 2, 3, or 4

Problem The compressor contactor for Ckt. 1, 2, 3, or 4 has malfunctioned.

Reason forDiagnostic

The circuit compressor proving input is detected closed continuously for more than three seconds while neither compressoroutput on that circuit closes.

ControlsReaction

A “lockout ckt #1, 2, 3, or 4” request is issued to the compressor staging control function.

ResetRequired (PMR) A manual reset is required after the diagnostic is set. It can be reset by the HI or Tracer Summit.

Compressor Trip—Ckt 1, 2, 3, or 4

Problem The compressor ckt #1, 2, 3, or 4 has tripped.

DDiiaaggnnoossttiiccss

108 SCXG-SVX01P-EN

Category Diagnostic


• The ckt #1, 2, 3, or 4 compressor proving input is detected open continuously for more than 3 seconds when either or bothcompressor outputs on that circuit energize (as described in the compressor protection function).

• The circuit compressor proving input is detected open continuously for more than 3 seconds when either or bothcompressor outputs on that circuit energize (as described in the compressor protection function).

ControlsReaction

A “lockout ckt #1, 2, 3, or 4” request is issued to the compressor staging control function.

ResetRequired

(PMR) A manual reset is required after this diagnostic occurs. The diagnostic can be reset by the unit mounted HI module orTracer Summit.

Condenser Temp Sensor Failure—Circuit 1, 2, 3, or 4

Problem The saturated condenser temperature input is out of range for circuit #1, 2, 3, or 4.

Check Sensor resistance should be between 830 ohms (200°F) and 345.7 ohms (-40°F). If so, check field/unit wiring between sensorand MCM/SCM.


The unit is reading a signal that is out of range for the circuit #1, 2, 3, or 4 saturated condenser temperature sensor. (temp <-55°F or temp > 209°F).

ControlsReaction

A “Lockout Ckt # 1, 2, 3, or 4” request is issued to the compressor staging control function.

ResetRequired

(PAR) An automatic reset occurs after the circuit 1, 2, 3, or 4 condenser temp input returns to its allowable range within 10seconds.

DDirty Filter

Problem There is a dirty filter.

Reason forDiagnostic The filter switch input on the RTM is closed for more than 60 seconds continuously.

ControlsReaction

An information only diagnostic is set.

ResetRequired (INFO) An automatic reset occurs after the dirty filter input reopens for 60 continuous seconds.

EECEM Communications Failure

Problem The RTM has lost communication with the ECEM.

Check Field/unit wiring between RTM and ECEMmodule.

Reason forDiagnostic The RTM has lost communication with the ECEM.

ControlsReaction

If the unit has the comparative enthalpy option, the economizer enable r.e. enthalpy function will revert to level 2 enthalpycomparison.

ResetRequired (PAR) An automatic reset occurs after communication has been restored.

Emergency Stop

Problem The emergency top input is open.


An open circuit has occurred on the emergency stop input caused either by a high duct temp t-stat trip, or the opening of field-provided contacts, switch, etc.


SCXG-SVX01P-EN 109

Category Diagnostic

ControlsReaction

Off or close requests are issued as appropriate to the following functions;

• Compressor staging/chilled water cooling control

• Heat operation

• Supply fan control and proof of operation

• Exhaust fan control and proof of operation.


• Outside air damper control

• On VAV units, VFD control

ResetRequired (PMR) A manual reset is required after the emergency stop input recloses. The diagnostic can be reset by the HI.

Entering CondenserWater Temperature Sensor Fail

ActivationConditions

Temperature < -50°F or temperature > 209°F, and unit configured for water-cooled condenser

Time toReact 10 sec < T < 20 sec

DiagnosticText

(HumanInterfaceDisplay)

“ENT CONDWATER TEMP SENSOR FAIL”

Actions tobe Initiated

A “Lockout All Ckts” request is issued to the “Compressor Staging Function”

Reset An automatic reset occurs after the entering condenser water temperature input returns to within range continuously for 15seconds.

EnteringWater Temperature Sensor Fail

Data used(module,packet,byte, bit)

WSM, 01,18,05


Temperature < -50°F or temperature > 209°F, and unit configured with water cooled condenser and/or economizer


DiagnosticText

(HumanInterfaceDisplay)

“ENTERING WATER TEMP SENSOR FAIL”


A “Disable Water Side Economizer” request is issued to “Water Side Economizer Temperature Enable Function”

Reset An automatic reset occurs after the Entering Water Temp. input returns to within range continuously for 10 seconds.

Evaporator Temperature Sensor Failure—Circuit 1, 2, 3, or 4

Problem The evaporator temperature sensor (ckt #1, 2, 3, or 4) is out of range.

Check Sensor resistance should be between 830 ohms (200°F) and 345.7Kohms (-40°F). If so, check field/unit wiring between sensorand MCM/SCM.


The unit is reading a signal that is out of range for the circuit #1 evaporator temperature sensor input (temp < -55°F or temp >209°F).

ControlsReaction

The coil frost protection function for the refrigeration circuit (#1, 2, 3, or 4) only is disabled.

ResetRequired (PAR) An automatic reset occurs after the #1, 2, 3, or 4 evaporator temp input returns to its allowable range for 10 seconds.


110 SCXG-SVX01P-EN

Category Diagnostic

GGBAS 0-5 VDCModule Communication Failure

Problem The RTM has lost communication with the GBAS module.

Check Field/unit wiring between RTM and GBAS.

Reason forDiagnostic The RTM has lost communication with the GBAS module.

Reaction

The UCM will initiate the following actions;

• If the demand limit input was closed prior to the communications loss, then the demand limit commands issued to the heatoperation function (if applicable) and the compressor staging/chilled water cooling function will be cancelled.

• If any of the GBAS setpoint control parameters are the HI-selected setpoint sources, then those setpoints will revert to thedefault HI setpoints.

• Any active GBAS output control parameters will be ignored.

• A failsafe function in the GBAS module will cause all GBAS outputs to be zeroed and de-energized.


HHeat Failure

Problem The heat has failed. (Electric heat unit)Typically, this is because the electric heat section became too hot.


The heat fail input on the heat module was closed:

• For more than 80 seconds,

• For ten consecutive occurrences (each lasting five seconds or more) within a 210 second period.

ControlsReaction

A n information only diagnostic is set.

ResetRequired (INFO) An automatic reset occurs after the heat fail input remains open for 210 seconds continuously.

Heat Module Auxiliary Temperature Sensor Fail

Problem The heat mod aux temp sensor input is out of range.

Check Sensor resistance should be between 830 ohms (200°F) and 345.7 ohms (-40°F). If so, check field/unit wiring between sensorand heat module.


At least one enabled unit function has the heat module auxiliary temperature input designated as its sensor, and the unit isreading a signal that is out of range for this input (temp < -55°F or temp > 209°F).

ControlsReaction

The functions that designated the heat module auxiliary temperature input as their input are disabled.

ResetRequired

(PAR) An automatic reset occurs after the heat module auxiliary temperature input returns to its allowable range for 10seconds.

Heat Module Comm Failure

Problem The RTM has lost communication with the heat module.

Check Check field/unit wiring between RTM and heat module.

Reason forDiagnostic The RTM has lost communication with the heat module.

ControlsReaction

• An “all heat off” request is sent to the heat operation function.

• If the unit has staged gas or electric heat, all heat module outputs will be zeroed and de-energized.

• If the unit has hydronic heat or chilled water installed, the unit will turn off the supply fan and close the outside air damperupon the occurrence of a heat module comm failure. A fail-safe function in the heat module will cause all water valves to beset to 100% to provide full water flow. Unless used for switching purposes (air handlers with chilled water and mod gas, orchilled water and hydronic heat) all binary outputs will be de-energized.


SCXG-SVX01P-EN 111

Category Diagnostic


LLow Air Temperature Limit Trip

Problem The low air temp limit has tripped. (Units with steam or hot water heating, or air handlers with chilled water cooling)


A low air temp limit trip is detected continuously for more than one second. This can occur if the hydronic heat low air temp limitinput closes for > 1 second, or if the chilled water low air temp limit trip input opens for > 1 second. On units with both hydronicheat and chilled water, both low air temp limit inputs are active, and the unit will respond in the samemanner regardless ofwhich input is used.

ControlsReaction

The UCM will initiate the following actions:

• An “open all water valves” request is issued to the heat module function, causing any steam, hot water, or chilled watervalves on the unit to open.

• An “all heat off” request is issued to the heat control function.

• A “fan off” request is sent to the supply fan control function.

• A “close damper” request is sent to the economizer actuator control function.

ResetRequired

(PMR) A manual reset is required after the low air temp limit trip condition clears. The diagnostic can be reset at the unitmounted human interface, by Tracer Summit, or by cycling power to the RTM.

Low Pressure Control Open—Circuit 1, 2, 3, or 4

Problem The Low Pressure Control (LPC) for Ckt #1, 2, 3, or 4 is open.

Check State of refrigerant charge for ckt #1, 2, 3, or 4.

Reason forDiagnostic The Ckt # 1 LPC input is detected open as described in the compressor protection function.

ControlsReaction

A “Lockout Ckt # 1, 2, 3, or 4” request is issued to the compressor staging control function.

ResetRequired

(PMR) A manual reset is required anytime after the diagnostic is set. The diagnostic can be reset by the human interface, TracerSummit, or by cycling power to the RTM.

MManual Reset SA Static Press Limit

Problem The supply air static pressure went too high for the third consecutive time.


The auto reset supply air static pressure limit diagnostic has occurred for the third time while the unit is operating in occupiedmode.

Reaction

A “supply air pressure shutdown” signal is sent to the following functions;

• Compressor staging control,

• Economizer actuator control,

• Heat operation,

• Supply fan control,

• VFD control,

• Exhaust fan control


ResetRequired (PMR) A manual reset is required and can be accomplished at the HI, Tracer Summit, or by cycling power to the RTM.

MCM Communications Failure

Problem The RTM has lost communication with the MCM.

Check Check field/unit wiring between RTM and MCM.

Reason forDiagnostic The RTM has lost communications with the MCM.


112 SCXG-SVX01P-EN

Category Diagnostic

ReactionA “Lockout” request is sent to the compressor staging control function. And a fail-safe function in the MCM will cause all MCMoutputs to be zeroed and de-energized.


Mode Input Failure

Problem The RTMmode input is out of range.

Check Sensor resistance should be between 1 ohm and 40 ohms. If so, check field/unit wiring between sensor and RTM.

Reason forDiagnostic The mode input signal on the RTM is out of range (resistance < 1 ohm or resistance > 40 ohms).

ControlsReaction

The systemmode reverts to the default (HI set) systemmode.

ResetRequired (INFO) An automatic reset occurs after the mode input returns to its allowable range for 10 seconds.

NNSB Panel Zone Temperature Sensor Failure

Problem The NSB panel's zone temp sensor input is out of range. (This input is at the NSB panel, not on the unit itself).

CheckIf have an external sensor connected to the NSB panel zone sensor input, then the internal NSB panel zone sensor should bedisabled. Verify sensor resistance. If in valid range, check wiring between the sensor and NSB panel.

NSB Panel Comm Failure

Problem The RTM has lost communications with the night setback panel (programmable zone sensor).

Check Field/unit wiring between RTM and NSB Panel.

Reason forDiagnostic The RTM has lost communication with the NSB panel.

ControlsReaction

The unit reverts to the next lower priority mode switching source (typically the HI default mode). If the NSB panel zone sensoris the designated sensor source for any functions, those functions are disabled.


OO/A Humidity Sensor Failure

Problem The outside air humidity sensor data is out of range.

Check Check field/unit wiring between the sensor and RTM.

Reason forDiagnostic The unit is reading a signal that is out of range for the outside air humidity sensor (humidity < 5% or humidity > 100%).

ControlsReaction

The economizer enable enthalpy function reverts to dry-bulb temperature changeover (“Level 1”) control.

ResetRequired (PAR) An automatic reset occurs after the OA humidity input returns to its allowable range for 10 seconds.

O/A Temp. Sensor Failure

Problem The outside air temperature sensor input is out of range.

Check Sensor resistance should be between 830 ohms (200°F) and 345.7 ohms (-40°F). If so, check field/unit wiring between sensorand RTM.


The unit is reading a signal that is out of range for the outside air temperature input on the RTM (temp. < -55°F or temp > 209°F).


SCXG-SVX01P-EN 113

Category Diagnostic

ControlsReaction

These unit functions occur:

• Low Ambient Compressor Lockout Disables

• O/A damper drives to minimum position

• On VAV units with S/A temp. reset type selected as O/A temp. reset, the reset type reverts to “none” for the duration of thefailure

ResetRequired

(PAR) an automatic reset occurs after the O/A temperature input returns to its allowable range. To prevent rapid cycling of thediagnostic, there is a 10 second delay before the automatic reset.

Occupied Zone Heat Setpoint Failure

Problem The occupied zone heat setpoint input is out of range.


The input designated as occupied zone heating setpoint source is out of range for the outside air temperature input on the RTM(temp. < 45°F or temp > 94°F).

Reaction The active occupied zone heating setpoint reverts to the default value.

ResetRequired

(PAR) an automatic reset occurs after the occupied zone heating setpoint input returns to its allowable range for 10 continuousseconds, or after a different occupied zone heating setpoint selection source is user-defined.

RReturn Air Humidity Sensor Failure

Problem On units with both airside economizer and comparative enthalpy installed, the return air humidity sensor input is out of range.

Check Check field/unit wiring between the sensor and ECEM.

Reason forDiagnostic The unit is reading a signal that is out of range for the return air humidity sensor (humidity < 5% or humidity > 100%).

Reaction The economizer enable r.e. enthalpy function reverts to reference enthalpy changeover (“Level 2”) control.

ResetRequired (PMR) An automatic reset occurs after the RA humidity input returns to its allowable range continuously for 10 seconds.

Return Air Temperature Sensor Failure

Problem On units with the comparative enthalpy option, the return air temperature sensor input is out of range.

Check Sensor resistance should be between 830 ohms (200°F) and 345.7 ohms (-40°F). If so, check field/unit wiring between thesensor and ECEM.

Reason forDiagnostic The unit is reading a signal that is out of range for the return air humidity sensor (temp < -55°F or temp > 209°F).

Reaction The economizer enable r.e. enthalpy function reverts to reference enthalpy changeover (“Level 2”) control.

ResetRequired (PAR) An automatic reset occurs after the RA temp input returns to its allowable range continuously for 10 seconds.

RTM Auxiliary Temperature Sensor Failure

Problem The RTM auxiliary temperature sensor data is out of range.

Check Sensor resistance should be between 830 ohms (200°F)and 345.7 ohms (-40°F). If so, check field/unit wiring between sensorand RTM.


At least one enabled unit function has the RTM auxiliary temperature input designated as its sensor, and the unit is reading asignal that is out of range for this input (temp. < -55°F or temp > 209°F).

ControlsReaction

The functions with the RTM auxiliary temperature input designated as their sensor are disabled.

ResetRequired

(PAR) an automatic reset occurs after the designated zone temperature signal returns to its allowable range. To prevent rapidcycling of the diagnostic, there is a 10 second delay before the automatic reset.

RTMData Storage Error

Problem There was a data transmission error.


114 SCXG-SVX01P-EN

Category Diagnostic

CheckThis can be caused by an intermittent power loss. Turn the unit off for 1-2 minutes, then back on again. If diagnostic persists,then the RTMmay need to be replaced.

Reason forDiagnostic An error occurred while the RTM was writing data to its internal non-volitile memory (EEPROM).

ControlsReaction

An information only diagnostic will be displayed at the human interface.

ResetRequired (INFO) A manual reset may be made at the human interface, at Tracer Summit, or by cycling power to the RTM.

RTM Zone Sensor Failure

Problem The RTM zone temperature sensor input is out of range.



At least one enabled unit function has the RTM zone temperature input designated as its sensor, and the unit is reading a signalthat is out of range for this input (temp. < -55°F or temp > 150°F).

ControlsReaction

The functions with the RTM zone temperature input designated as their sensor are disabled.

ResetRequired

(PAR) an automatic reset occurs after the designated zone temperature signal returns to its allowable range. To prevent rapidcycling of the diagnostic, there is a 10 second delay before the automatic reset.

SSCM Communication Failure

Problem The RTM has lost communication with the SCM.

Check Check field/unit wiring between the RTM and SCM.

Reason forDiagnostic The RTM has lost communication with the SCM.

ControlsReaction

A “lockout” request is sent to the compressor staging control function. A fail-safe function in the SCM will cause all SCM outputsto be zeroed and de-energized.


Space Static Press Setpoint Failure

Problem The active space static pressure setpoint is out of range.

CheckCheck setpoint value. Also, if space pressure setpoint source is GBAS, but this setpoint has not been assigned to any of the fouranalog inputs on GBAS, this message will occur.

Reason forDiagnostic The unit is reading a signal that is out of range for the space static pressure setpoint (input < 0.03 iwc or input > 0.20 iwc).

ControlsReaction

The default space pressure setpoint will become the active space pressure setpoint.

ResetRequired

(PAR) An automatic reset occurs after the designated space pressure setpoint source sends a signal within range for 10continuous seconds, or after a different space pressure setpoint source is user-defined.

Supply Air Pressure Sensor Failure

Problem The supply air pressure sensor voltage input is out of range.

Check Check field/unit wiring between the sensor and RTM.

Reason forDiagnostic The unit is reading a signal that is out of range for the supply air pressure sensor voltage input (input < 40mV or input > 4.75V)

ControlsReaction

The following functions are disabled;

• SA pressure control

• SA static pressure limit


SCXG-SVX01P-EN 115

Category Diagnostic

ResetRequired

(PAR) An automatic reset occurs after the SA temp heating setpoint input returns to within range for 10 continuous seconds, orafter a different SA temp heating setpoint selection source is user-defined.

Supply Air Pressure Setpoint Failure

Problem The SA pressure input signal is out of range.

Reason forDiagnostic The SA pressure setpoint input is sending a signal that is out of range (Input < 1.0 iwc or input > 4.3 iwc)

ControlsReaction

The default SA pressure setpoint will become the active SA pressure setpoint.

ResetRequired

(PAR) An automatic reset occurs after the designated SA pressure setpoint source sends a signal within range for 10 continuousseconds, or after a different SA pressure setpoint source is user-defined.

Supply Air Temperature Cool Setpoint Fail

Problem The active supply air temperature cooling setpoint is out of range.

Reason forDiagnostic The input designated as the SA temp cooling setpoint is out is out of range (temp < 35°F or temp > 95°F).

ControlsReaction

The default HI-set SA temp cooling setpoint becomes the active SA temp cooling setpoint.

ResetRequired

(PAR) An automatic reset occurs after the SA temp cooling setpoint input returns to within range for 10 continuous seconds, orafter a different SA temp cooling setpoint selection source is user-defined.

Supply Air Temperature Heat Setpoint Fail

Problem The active supply air temperature cooling setpoint is out of range.

Reason forDiagnostic The input designated as the SA temp heating setpoint is out is out of range (temp < 35°F or temp > 185°F).

ControlsReaction

The default HI-set SA temp heating setpoint becomes the active SA temp heating setpoint.

ResetRequired

(PAR) An automatic reset occurs after the SA temp heating setpoint input returns to within range for 10 continuous seconds, orafter a different SA temp heating setpoint selection source is user-defined.

Supply Air Temperature Failure

Problem The supply air temperature sensor input is out of range.



The unit is reading a signal that is out of range for the supply air temperature input on the RTM (temp. < -55°F or temp > 209°F).

ControlsReaction

These unit functions are disabled:

• Supply air tempering

• Economizing

• Supply air temperature low limit function (CV units)

• Supply air temperature control heating and cooling functions (VAV units)

ResetRequired

(PAR) an automatic reset occurs after the designated S/A temperature input returns to its allowable range. To prevent rapidcycling of the diagnostic, there is a 10 second delay before the automatic reset.

Supply Fan Failure

Problem There is no supply airflow indication after the supply fan is requested on.

CheckCheck belts, linkages, etc. on the supply fan assembly. If these are ok, check field/unit wiring between RTM and supply fan. Ifthe supply fan runs in service mode, then verify airflow proving switch and wiring.


• The supply airflow input is detected OPEN for 40 continuous seconds during any period of time in which the supply fanbinary output is ON. between 830 ohms (200°F) and 345.7 ohms (-40°F). If so, check field/unit wiring between the sensorand MCM.

• This input is ignored for up to 5 minutes after the supply fan starts, until airflow is first detected.


116 SCXG-SVX01P-EN

Category Diagnostic

ControlsReaction

“Off” or “Close” requests are issued as appropriate to the following functions;

• Compressor staging/chilled water control

• Heat operation

• Supply fan control & proof of operation

• Exhaust fan control & proof of operation


• Economizer actuator control

• VFD control

ResetRequired

(PMR) A manual reset is required anytime after the diagnostic is set. The diagnostic can be reset at the HI, Tracer Summit, or bycycling power to the RTM.

Supply Fan VFD Bypass Enabled


RTM

Activationconditions

Supply fan VFD bypass has been activated and supply fan vfd bypass is installed.


Diagnostictext

(humaninterfacedisplay)

“SUPPLY FAN VFD BYPASS ENABLED”

Actions tobe Initiated NONE

Reset The INFO diagnostic is cleared when the supply fan VFD bypass is deactivated.

TLCI Module Comm Failure

Problem The RTM has lost communication with the LCI.

Check Check field/unit wiring between RTM and LCI module.

Reason forDiagnostic The RTM has lost communication with the LCI module.

ControlsReaction

All active commands and setpoints provided by Tracer Summit through the LCI will be canceled and/or ignored. And whereTracer Summit has been designated as setpoint source, local HI default setpoints will be used.


Tracer Communications Failure

Problem LCI has lost communication with Tracer Summit.

CheckTracer Summit (building control panel) is powered up and running properly. If so, check unit wiring between LCI and TracerSummit (building control panel).

Reason forDiagnostic The LCI has lost communications with Tracer Summit for > 15 minutes.

ControlsReaction

All active commands and setpoints provided by Tracer Summit through the LCI will be canceled and/or ignored. And whereTracer Summit has been designated as the setpoint source, local HI default setpoints are used.

ResetRequire (PAR) An automatic reset occurs after communication between Tracer Summit and the LCI is restored.

U


SCXG-SVX01P-EN 117

Category Diagnostic

Unit HI Communications Failure

Problem The RTM has lost communication with the unit mounted (local) human interface (HI).

Check Field/unit wiring between RTM hand local HI.

Reason forDiagnostic The RTM has lost communication with the unit-mounted human interface.

ControlsReaction

A fail-safe function in the HI will cause the following sequence:

1. Disallow any interaction between the HI and the RTM (or any other modules)

2. Render all HI keystrokes ineffective

3. Cause the following message to display on the unit-mounted HI display: “Local HI communications loss. Check comm linkwiring between modules.” If the unit has a remote HI option, then this diagnostic will display as any other automatic resetdiagnostic.

ResetRequired

(INFO) An automatic reset occurs after communication is restored between the RTM and the HI. When the failure screen clears,the general display restores to allow the HI to interact with the RTM again.

Unoccupied Zone Cool Setpoint Failure

Problem The unoccupied zone cooling setpoint input is out of range.

Reason forDiagnostic The input designated as the unoccupied zone cooling setpoint source is out of range (temp < 45°F or temp > 94°F).

ControlsReaction

The active unoccupied zone cooling setpoint reverts to the default value.

ResetRequired

(PAR) An automatic reset occurs after the designated unoccupied zone cool setpoint input returns to its allowable range for 10continuous seconds, or after the user defines a different, valid unoccupied zone cool setpoint selection source.

Unoccupied Zone Heat Setpoint Failure

Problem The unoccupied zone heating setpoint input is out of range.

Reason forDiagnostic The input designated as unoccupied zone heating setpoint source is out of range (temp < 45 F or temp > 94 F).

ControlsReaction

The active unoccupied zone heating setpoint reverts to the default value.

ResetRequired

(PAR) An automatic reset occurs after the designated unoccupied zone heat setpoint input returns to its allowable range for 10continuous seconds, or after the user defines a different, valid unoccupied zone heating setpoint selection source.

VVCM Communication Failure

Problem The RTM has lost communication with the VCM.

Verify Check field/unit wiring between RTM and VCM.

Reason forDiagnostic RTM has lost communication with VCM.

ControlsReaction

All active commands and setpoints provided by the VCM are canceled and/or ignored. A fail-safe function in the VCM will causeall outputs to de-energize and/or set to zero. The outside air damper minimum position function will revert to using the O/Aflow compensation function if O/A flow compensation is enabled or set to the default minimum position function if O/A flowcompensation is disabled or not available.

ResetRequired (PAR) An automatic reset occurs after communication is restored.

Velocity Pressure Sensor Failure

Problem The velocity pressure input signal is out of range.

Check Check field/unit wiring between sensor and VCM.


The unit is reading a signal that is out of range for the velocity pressure transducer input (during calibration: V < 40 mV or V >420 mV, during operation: V < 40 mV or V > 0.75 V).


118 SCXG-SVX01P-EN

Category Diagnostic

ReactionThe minimum airflow control function is disabled. The outside air damper minimum position function reverts to using the O/Aflow compensation function if O/A flow compensation is enabled or to the default minimum position function if O/A flowcompensation is disabled or not available.

ResetRequired

(PAR) An automatic reset occurs after the designated space pressure transducer sends a signal within range for 10 continuousseconds.

VOM Communications Failure

Problem The RTM has lost communication with the VCM.

Check Field/unit wiring between RTM and VCM.

Reason forDiagnostic The RTM has lost communications with the VOM.

ControlsReaction

Ventilation override actions will not be allowed, and the VO Output relay will be de-energized.


WWSMCommunications Fail

Problem The RTM has lost communication with the WSM.

Check Field/unit wiring between RTM and WSM.

Reason forDiagnostic RTM has lost communication with WSM.

ControlsReaction

UCM will react as if a freezestat has occurred by issuing:

• “All heat on” or “mod output full open” request to “heat control”

• A “fan off” request to “supply fan control”

• “Close damper” request to “economizer actuator control”

• Water pump to turn on and position all water valves to provide maximum flow through all water source heat exchangers

• Disables preheat function if WSMmixed air temp sensor is selected as preheat sensor

ResetRequired An automatic reset occurs after one complete set of IPC packets is received.

WSMMixed Air Temp Sensor Fail


Temperature <-50°F or temperature >209°F, and sensor is selected for use by “waterside economizer temperature enablefunction” or “preheat function”



“Waterside economizer temperature enable function” uses supply air cooling setpoint instead of mixed air temperature. Ifmixed air temperature is used for “preheat function”, issue a “disable” request to “preheat function”.

Reset An automatic reset occurs after mixed air temp. input returns to within range continuously for 10 seconds.

Water Flow Fail


WSM, 01,19, 05


Water flow input is detected open:

• At the end of pre-cool water flow initiation state, or

• Continuously for five minutes while:

– Water side economizer is open 100%,

– Presetting of a head pressure valve, or

– Demand for mechanical cooling.


SCXG-SVX01P-EN 119

Category Diagnostic

Unit mustbe

Configured with water cooled condenser and/or water economizer and have water flow switch installed.

Time toReact Immediate


A “lockout all ckts” request is issued to the “compressor staging function”

Reset Automatic reset occurs after water flow input returns to within range continuously for 3 seconds, water pump is requested OFF,or water flow switch becomes not installed.

ZZone Cool Setpoint Failure

Problem Occupied zone cooling setpoint is out of range.

Reason forDiagnostic Input designated as occupied zone cooling setpoint source is out of range (temp. < 45°F or > 94°F).

ControlsReaction

The active occupied zone cooling setpoint reverts to the default occupied zone cooling setpoint.

ResetRequired

(PAR) an automatic reset occurs after designated occupied zone CSP input returns to its allowable range for 10 continuousseconds, or after a different valid occupied zone CSP selection source is user-defined.


120 SCXG-SVX01P-EN

Wiring Diagrams

NNoottee:: For easier access, published unit wiringdiagrams (individual, separate diagrams forunitary product lines) will become available via

e-Library instead of through wiring manualsafter 2007.

Number Description

2307-8264 Field Wiring DiagramW/VFD S*WG 20 -35T & S*RF 20-32T

2307-8266 Schematic DiagramWith VFDW/Bypass RTM Module S*WG 20-35T S*RG 20-32T

2307-8272 Schematic DiagramWith VFDW/Bypass S*WG 20-35T S*RG 20-32T

2307-8273 Schematic DiagramWith VFDW/O Bypass RTM Module S*WG 20-35T S*RG 20-32T

2307-8288 Connection DiagramWith VFDW/ or W/O Bypass S*WG 20-35T S*RG 20-32T

2307-8419 Schematic DiagramWith VFDW/Bypass Dual Power S*WG 20-35T S*RG 20-32T

2307-8423 Connection DiagramWith VFDW/Bypass S*WG 20-35T S*RG 20-32T

2307-8265 Schematic Diagram CV S*WG 20-35T S*RG 20-32T

2307-8417 Schematic Diagram CV Dual Point Pwr S*WG 20-35T S*RG 20-32T

2307-8271 Schematic DiagramW/VFD Single Point Pwr S*WG 20-35T S*RG 20-32T

2307-8418 Schematic DiagramW/VFD Dual Point Pwr S*WG 20-35T S*RG 20-32T

2307-8267 Schematic Diagram CV RTM Module S*WG 20-35T S*RG 20-32T

2307-8268 Schematic DiagramWater-Cooled S*WG 20-35T

2307-8274 Schematic Diagram Air-Cooled S*RG 20-32T

2307-8269 Schematic Diagram Heat, Vent Cntrl & GBAS S*WG 20-35T S*RG 20-32T

1213-1748 Schematic Diagram ECEM, VOM LCI, IPCB, HI & RHI Mod S*WG 20-35T S*RG 20-32T

2307-8285 Connection Diagram CV S*WG 20-35T S*RG 20-32T




2307-8289 Connection DiagramW/VFDW/Bypass S*WG 20-35T S*RG 20-32T

2307-8290 Connection DiagramW/VFDW/Bypass S*WG 20-35T S*RG 20-32T

2307-8291 Connection Diagram Thermostat Interface S*WG 20-35T S*RG 20-32T

2307-8421 Connection Diagram Thermostat Interface S*WG 20-35T S*RG 20-32T

2307-8346 Lower 37 PIN CPC Connector S*WG 20-35T S*RG 20-32T

2307-8350 Upper 37 PIN CPC Connector S*WG 20-35T S*RG 20-32T

2307-8457 Electric Heat 9 PIN Connector S*WG 20-35T S*RG 20-32T

2307-8359 Field Wiring Diagram Ipak Controls CCRC 20-60 Ton

2307-8360 Schematic Diagram Thermostat Controls CCRC 20, 29 & 32 Ton

2307-8361 Schematic Diagram Thermostat Controls CCRC 20, 29 & 32 Ton

2307-8362 Connection Diagram Thermostat Controls CCRC 20, 29 & 32 Ton

2307-8363 Connection Diagram Thermostat Controls CCRC 20, 29 & 32 Ton

2307-8364 Field Wiring Diagram Thermostat Controls CCRC 20, 29 & 32 Ton

SCXG-SVX01P-EN 121

Number Description

2307-8332 Schematic Diagram Ipak Controls CCRC 20, 29 & 32 Ton

2308-8284 Connection DiagramWith Ipak Controls CCRC 20-60 Ton

WWiirriinngg DDiiaaggrraammss

122 SCXG-SVX01P-EN

NNootteess

SCXG-SVX01P-EN 123

NNootteess

Trane - by Trane Technologies (NYSE: TT), a global innovator - creates comfortable, energy efficientindoor environments for commercial and residential applications. For more information, please visittrane.com or tranetechnologies.com.

Trane has a policy of continuous product and product data improvements and reserves the right to change design and specifications withoutnotice. We are committed to using environmentally conscious print practices.

SCXG-SVX01P-EN 10 Apr 2020

Supersedes SCXG-SVX01N-EN (June 2018) ©2020 Trane

Documents

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