IM-801 Page 1

Installation and Maintenance Manual IM-801

Group: Unitary

Part Number: IM-801

Date: August 2005

Supersedes: January 2005

AHP Split System Heat Pumps1-1/2 to 5 tons

© 2004 McQuay International

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Table of ContentsMODEL NOMENCLATURE. . . . . . . . . . . . . . . . . . . . . . . . . . 3INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4GENERAL WARNINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4SCROLL COMPRESSORS . . . . . . . . . . . . . . . . . . . . . . . . . 4INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5ELECTRICAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6PIPING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6EVAPORATOR COIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

INDOOR CFM AND HEATING CAPACITY DETERMINATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 REFRIGERANT CHARGE DETERMINATION AND ADJUSTMENT - HEAT PUMP - COOLING CYCLE . . . . . .10HEAT PUMP - HEATING CYCLE . . . . . . . . . . . . . . . . . . . .11STARTUP PROCEDURE AND CHECK LIST . . . . . . . . . . .11OPERATION - DEFROST CONTROL . . . . . . . . . . . . . . . .12MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14THERMOSTAT DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . .15

"McQuay" is a registered trademark of McQuay International.© 2004 McQuay International

"Illustrations and information cover the McQuay International products at the time of publication and we reserve the right to make changes in design and construction at any time without notice."

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MODEL NOMENCLATURE

Table 1: Unit Nameplate Model Number Identifier

ModelAHP= Air Cooled Heat Pump

Nominal Capacity (tons)18 = 1-1/2 24 = 2 36 = 3 42 = 3-1/2 48 = 449 = 460 = 561 = 562 = 5

Future Use

Voltage/PhaseP = 208-230/3/60*R = 208-230/1/60

SEERA = 10B = 12C = 13

Vintage

AHP 018 A R A Y

* 10 SEER Size 048 and 060 only.

Unit Nameplate McQuay Model NumberCPLE18-1C AHP018ARAYCPLE24-1C AHP024ARAYCPLE30-1C AHP030ARAYCPLE36-1C AHP036ARAYCPLE42-1C AHP042ARAYCPLE48-1C AHP048ARAYCPLE48-3C AHP048APAYCPLE60-1C AHP060ARAYCPLE60-3C AHP060APAYCPLJ18-1B AHP018ARBYCPLJ24-1B AHP024ARBYCPLJ30-1B AHP030ARBYCPLJ36-1B AHP036ARBYCPLJ42-1B AHP042ARBYCPLJ48-1B AHP048ARBYCPLJ60-1B AHP060ARBYCPLT24-1B AHP024ARCYCPLT30-1B AHP030ARCYCPLT36-1B AHP036ARCYCPLT42-1B AHP042ARCYCPLT48-1B AHP048ARCYCPLT60-1B AHP060ARCY

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INTRODUCTIONGeneral DescriptionThese installation instructions cover the outdoor installation ofsplit system heat pumps from ½ to 5 tons. See the product cat-alog applicable to your model for information regarding speci-fications applicable to your model and accessories.Receiving InspectionMcQuay products are carefully inspected prior to shipmentand the carrier has assumed responsibility for loss or damageupon acceptance of the shipment. Upon receiving your shipment, check all items carefullyagainst the Bill of Lading. Inspect the unit and/or accessoriesfor shipping damage as soon as they are received. Immedi-ately file claims for loss or damage, either shipping or con-cealed, with the shipping company. Check the unit nameplate to verify the model number and elec-trical characteristics are correct. In the event an incorrect unitis shipped, it must be returned to the supplier and must NOTbe installed. The manufacturer disclaims all responsibility forthe installation of incorrectly shipped units.Codes and RegulationsThis product is designed and manufactured to permit installa-tion in accordance with National Codes. System designshould, where applicable, follow information presented inaccepted industry guides such as the ASHRAE Handbooks. Itis the installer' s responsibility to install the product in accor-dance with National Codes and/or prevailing local codes andregulations. The manufacturer disclaims all responsibility forequipment installed in violation of any code or regulations.

Important Message to the InstallerThis equipment is to be installed by an experienced installationcompany and fully trained personnel. Carefully read allinstructions and take into account any special considerationsprior to installing the unit. Give this manual to the owner andexplain its provisions. Important Message to the OwnerRead these instructions carefully and keep them near the prod-uct for future reference. Although these instructions areaddressed primarily to the installer, useful maintenance infor-mation is included. Have the installer acquaint you with theoperation of the product and periodic maintenance require-ments.

Recognize Safety Symbols, Words, and LabelsThe following symbols and labels are used throughout thismanual to indicate immediate or potential hazards. It is theowner's and installer's responsibility to read and comply withall safety information and instructions accompanying thesesymbols. Failure to heed safety information increases the riskof property damage and/or product damage, serious personalinjury or death. Improper installation, operation and mainte-nance can void the warranty.

Replacement PartsReplacement parts can be obtained by contacting McQuay at1-800-37-PARTS. When contacting McQuay for service orreplacement parts, refer to the model number and serial num-ber of the unit as stamped on the nameplate attached to theunit.

GENERAL WARNINGS

SCROLL COMPRESSORSRead the following before installing units with scroll compres-sors.Pump Down ProcedureScroll-equipped units should never be used to evacuate the airconditiong system. Vacuums this low can cause internal elec-trical arcing, resulting in a damaged or failed compressor.Crankcase HeaterScroll-equipped units do not have, and do not require, a crank-case heater.

Unbrazing System ComponentsIf the refrigerant charge is removed from a scroll equipped unitby bleeding the high side only, it is sometimes possible for thescrolls to seal, preventing pressure equalization through thecompressor. This may leave the low side shell and suction linetubing pressurized. If a brazing torch is then applied to the lowside while the low side shell and suction line contains pressure,

IMPORTANT

The United States Environmental Protection Agency (EPA) regulations cover introduction and disposal of refrigerants in this unit. Failure to follow those regulations can harm the environment and lead to substantial fines. Because regulations can change, a certified technician should perform any work done on this unit. If you have any questions, please contact the local office of the EPA.

DANGERImmediate hazards which WILL result in property damage, product damage, severe personal injury and/or death.

WARNINGHazards or unsafe practice CAN result in property damage, product damage, sever personal injury and/or death.

CAUTIONHazards or unsafe practices which CAN result in property damage, product damage, and/or personal injury.

WARNINGDo not allow combustible materials, gasoline or other flammable liquids or vapors in the vicinity of this unit. Property damage, severe personal injury or death can result. Identify all cut-off devices, switches, etc. that serve your comfort equipment.

WARNINGDo not connect duct work to any other heat-producing device such as fireplace insert, stove, etc. Such connection can cause property damage, fire, carbon monoxide poisoning, explosion, personal injury or death.

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the pressurized refrigerant and oil mixture could ignite when itescapes and contacts the brazing flame. To prevent this occur-rence, it is important to check both the high and low side witha manifold gauge before unbrazing, or in the case of repairinga unit on an assembly line, bleed refrigerant from both the highand low side.

INSTALLATIONThe manufacturer intends this unit to be used only with com-ponents indicated. An improper match voids the warranty.See the unit catalog for Performance Values and ApprovedSystem Matches.Pre-Installation CheckpointsPerform pre-installation checkpoints before attempting anyinstallation. Consider the following check points:• Structural strength of supporting members • Clearances and provision for servicing• Power supply and wiring• Air duct connections• Drain facilities and connectionsClearanceThe outdoor heat pump unit is designed to be located outsidethe building with unobstructed condenser air inlet and dis-charge. Additionally, the unit must be situated to permit accessfor service and installation. Condenser air enters from threesides. Air discharges upward from the top of the unit. Refrig-erant tube electrical connections are made on the right side ofthe unit as you face the compressor compartment. The bestand most common application is for the unit to be located 10”from a back wall with the connection side facing the wall.This “close to the wall” application minimizes exposed tubingand wiring and reduces the space for children to run around theunit, which can damage the tubes or wiring.Figure 1. Clearances and Accessibility

Close to the wall application provides free, unobstructed air tothe other two sides. In more confined application spaces, suchas corners, provide a minimum 10” clearance on all air inletsides. Allow 18” minimum for service access to the compres-sor compartment and controls.

The top of the unit should be completely unobstructed. If unitsare to be located under an overhang, there should be a mini-mum of 36” clearance and provisions made to deflect thewarm discharge air out from the overhang.

LocationConsider the effect of outdoor fan noise on the conditionedspace and any adjacent occupied space. Place the unit so thedischarge does not blow toward windows less than 25 feetaway.

Set the outdoor unit on a solid, level foundation - preferably aconcrete slab at least 4 inches thick. The slab should be aboveground level and surrounded by a graveled area for good drain-age. Any slab used as a unit foundation should not adjoin thebuilding, as it is possible that sound and vibration may betransmitted to the structure. For rooftop installation, use steelor treated wood beams as a unit support for load distribution.

Heat pumps require special location consideration in areas ofheavy snow accumulation and/or areas with prolonged contin-uous subfreezing temperatures. Heat pump unit bases are cut-out under the outdoor coil to permit drainage of frostaccumulation. The unit must be situated to permit free, unob-structed drainage of the defrost water and ice. A minimum 3"clearance under the outdoor coil is required in the milder cli-mates.

In more severe weather locations, elevate the unit to allowunobstructed drainage and air flow. Table 2 lists recommendedelevation minimums:

Table 2: Elevation Minimums

Elevation LimitationsIf the outdoor unit is mounted above the air handler, the maxi-mum lift should not exceed 70 feet (suction line). If the airhandler is mounted above the outdoor unit, the lift should notexceed 50 feet (liquid line).

Note: When installing systems where the indoor - outdoorsections are separated by more than 15 feet, observethe maximum elevation separations limitations.

WARNINGBefore unbrazing, check pressure on both high and low side. Incorrect charge removal can leave pressurized refrigerant and oil, which can ignite in contact with brazing heat, causing property damage and severe personal injury.

Service Access18" Min.

Service Access18" Min.

10"

10"

10"

10"

20"

Design Temperature Suggested Minimum Elevation

+15o and above 2 1/2"

-5o to + 14o 8"

below -5o 12"

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Figure 2. Maximum Refrigerant Line Lengths

ELECTRICAL

The supply power, voltage, frequency and phase must coincidewith those listed on the nameplate. Carefully check all wiringagainst the manufacturer’s diagrams or with the diagram onthe unit’s access panel. Field wiring must be connected inaccordance with the National Code or other local codes thatmay apply. Verify that the equipment is adequately groundedper local code requirements. Use only copper wire between thedisconnect and unit.

Over-current protection less than what is recommended in theunit catalog could result in unneccessary fuse failures and ser-vice calls. The manufacturer is not responsible for equipmentdamage resulting from not using the recommended size protec-tive devices as listed on the unit rating plate.

This unit has undergone a run test prior to packaging for ship-ment. This equipment has been started at minimum rated volt-age and checked for satisfactory operation. Do not attempt tooperate this unit if the available voltage is not within the mini-mum and maximum shown on nameplate.

The condensing unit control wiring requires a 24-Volt mini-mum and a 40 VA service from the indoor transformer asshown on the wiring diagram.

COMPONENTSContactorThis control is activated (closed) by the room thermostat forboth heating and cooling. It is de-energized (open) duringemergency heat. The contactor has a 24-Volt coil and suppliespower to the compressor and outdoor fan motor.

Crank Case HeaterThe heater is factory wired so it is in operation whenever themain power supply to the unit is “ON”. It warms the compres-sor crankcase, preventing liquid migration and subsequentcompressor damage. It is connected electrically to the contac-tor L1 and L2 terminals.

Condenser MotorThis is activated by the contactor during heating and coolingexcept during defrost and emergency heat operation.

CompressorThis is activated by the contactor for heating and coolingexcept during emergency heat. It is protected by an internaloverload device.

Defrost ControlThis provides time/temperature initiation and termination ofthe defrost cycle.

Loss of Charge ProtectorIf the system loses refrigerant charge, the control will open toallow the compressor contactor to open.

Outdoor ThermostatsThese optional controls are used to prevent full electric heateroperation at varying outdoor ambient (0°F to 45°F). They arenormally open above their set points and closed below to per-mit staging of indoor supplemental heater operation.

Reversing Valve CoilThis is activated by the thermostat (system’s switch) duringcooling only and during defrost. It positions the reversingvalve pilot valve for cooling operation.

PIPINGOnce located, the outdoor unit is ready to be interconnectedwith the indoor section, using the refrigeraion tubing sizesnoted in the “Long Line Recommendations” Table. Use onlyrefrigeration grade (dehydrated and capped) copper tubing.

Use insulation of at least 1/2” wall thickness on the vapor gasline to prevent condensation when cooling and heat loss whenheating. Install the insulation on the tubing prior to unit instal-

WARNINGBefore attempting any service or adjustments, lock and tag out all gas and electrical supplies. Failure to follow this warning can cause property damage, personal injury and or death.

CONDENSING UNITPITCH SUCTION LINE TOWARD OUTDOORUNIT 1/2" FOR EVERY 10' OF LINE

EVAPORATOR BLOWER

LIQUID LINE

CONDENSING UNIT

EVAPORATOR BLOWER

70' MAX

ADDITIONAL SUCTION LINE OIL TRAP FOR EACH 20' RISE OF PIPE

LIQUID LINESUCTION LINE OIL TRAPS WHEN INDOOR UNITIS 4 FEET OR MORE BELOW OUTDOOR UNIT

CONDENSING UNIT EVAPORATOR BLOWER

LIQUID LINE

SUCTION LINE

INVERTED LOOP

50' MAX

8'

CCAUTIONBefore starting equipment after prolonged shut-downs or at the time of initial start up, verify that the circuits to the units are closed for at least 24 hours.

CCAUTIONKeep refrigeration tubing clean and dry prior to and during installation to avoid equipment damage.

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lation. Run the insulation the entire length of the installed line.Cover the end of the tubing over which the insulation isslipped so no foreign material is introduced to the interior ofthe tubing. The outdoor units are equipped with two refriger-ant line service valves. As shipped, the valves are in the front-seated or “down” position.

Line Set Installation InstructionsUse the following instructions to install line sets:

1. Cut tubing square. Verify it is round and free of burrs at theconnecting ends. Clean the tubing to prevent contaminantsfrom entering the system.

2. Wrap a wet rag around the copper valve stub before braz-ing.

3. Braze or silver solder the joint.

4. After brazing, quench with a wet rag to cool the joint.Evacuate and charge the connecting lines as outlined inthese instructions.

5. Remove the valve top cap. It is important to keep the capin a clean area to provide proper sealing once replaced.

6. Using a standard L-shaped Allen wrench, break open thevalve body. To expedite opening the valve body after it isbroken, use a ratchet wrench with a short Allen stub.Please note that it is normal to see oil on the valve stembody once the cap is removed.

7. Replace the valve cap and tighten with a wrench. Verifythat the the cap is sealed.

Table 3: Long Line Recommendations

* 7/8" required for full ratings** 1 1/8" required for full ratings

EVAPORATOR COIL

The indoor coil is pressurized. The copper caps must be punc-tured to permit a gradual escape of the pressure prior to un-sweating caps. Immediately couple the tubing to the indoorunit to avoid exposing the coils to moisture. A properly sizedfilter drier is furnished in the condenser. When heating thecopper to make solder connections, use a dry nitrogen flowthrough the line to prevent oxidization inside of the copper.

Hard solder (Sil-Fos) is recommened, to provide a longer last-ing joint.

INDOOR CFM AND HEATING CAPACITY DETERMINATIONPrior to using the methods described below to check the sys-tem’s charge, it is important to verify the operating capacity ofthe system and that the system is delivering sufficient airacross the indoor coil (CFM). The following procedures aresuggested methods for determining the system’s operatingcapacity and CFM.

Airflow Determination - Indoor CoilThe heat pump system has been designed for optimum perfor-mance with an airflow across the indoor coil equaling approxi-mately 400 CFM/TON (e.g. A 2 TON system should have 2 x400 CFM/TON = 800 CFM). The system’s airflow can bedetermined by several methods.

Airflow Test Instruments There are a number of readily available instruments that can beused in the field for airflow determination such as Barometers,Volume-Aire Air Balancers, Anemometers, and Velometers.When using these devices, it is important to follow the instruc-tions provided by their manufacturer.

Temperature Rise Resistive Heat MethodAlthough it is not as accurate as the use of test equipment, theTemperature Rise Method can be used to determine the indoorairflow in a system employing electric resistance heat as thebackup heat source.The following formula is used:

WHERE

e.g. :

The input power to the indoor section = 10 KW

The Temperature Rise = 20°F

Refer to the Airflow Measurement Table.

Note: The compressor circuit (outdoor unit) must be“OFF” so that the Temperature Rise measuredacross the indoor unit is due only to the electric heat.

REFRIGERANT LINE LENGTH (Ft)

Cond Unit Tons

0-24 25-49 50-74***Line Diameter (In. OD)

Suct Liq Suct Liq Suct Liq1 1/2 5/8 1/4 3/4 3/8 3/4 3/8

2 5/8 1/4 3/4* 3/8 3/4 3/82 1/2 3/4 3/8 3/4** 3/8 7/8 3/8

3 3/4 3/8 3/4** 3/8 7/8 3/83 1/2 3/4 3/8 7/8** 3/8 1 1/8 3/8

4 7/8 3/8 1 1/8 3/8 1 1/8 3/85 7/8 3/8 1 1/8 3/8 1 1/8 3/8

CCAUTIONEvaporator coils are shipped under high pressure. Use extreme care and follow the installation instruc-tions provided with the evaporator coil to avoid per-sonal injury.

KW = The indoor section’s measured input = Volts x AmpsVolts = The measured Volts at the Indoor SectionAmps = The measured Amps at the Indoor SectionTemperature Rise =

The temperature of the supply air - the temperature of the return air

3413 = BTU per KW1.08 = Specific Heat Air Constant

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Use the following instructions to determine the temperaturerise across the indoor section:

1. Use the same thermometer for the measuring the return andsupply air temperatures to avoid thermometer error.

2. Measure the temperatures within 6 feet of the indoor sec-tion and downstream from any mixed air source. Verifythat the thermometer is not exposed to any radiant heatareas.

3. Verify that the air temperature is stable before making mea-surement.

Figure 3. Temperature Rise Measurement

Temperature Rise Heat Pump Only MethodThe Temperature Rise Resistive Heat Method can be used todetermine the heating capacity of the heat pump system in theheat pump “only” mode. The results obtained using thismethod should agree within 10% of the data published in theunit catalog for the combination of indoor and outdoor sec-tion.

Note: When using the following procedure to determinethe system’s capacity, verify that the indoor sectionbackup heat source is de-energized.

1. Use the same procedure described in the Temperature RiseResistive Heat Method to determine the system’s CFM andtemperature rise across the indoor section.

2. Determine the BTU output of the system for the measuredTemperature Rise and system CFM by using the followingformula:

BTU = CFM x TEMPERATURE x 1.08

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Table 4: Airflow Measurements

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REFRIGERANT CHARGE DETERMI-NATION AND ADJUSTMENT - HEAT PUMP - COOLING CYCLEWeigh In Charge MethodTo verify that the heat pump system is properly charged,weigh in the amount of refrigerant specified on the outdoorsection nameplate, with additional adjustments for line size,line length and other system components. Heat Pump units aresupplied with an R-22 charge sufficient for a typical matchingevaporator and approximately 15 ft. of inner-connecting tub-ing. Systems having more than 15 ft of interconnecting refrig-erant lines require an additional charge allowance of R-22.

Table 5: Line Charge Allowance (R-22-oz./lb.)

Superheat MethodThe following information has been developed to determinethe proper charge for McQuay heat pump systems that arealready in operation.

Note: Many field variations exist that may affect the oper-ating temperature and pressure readings of a heatpump system. All McQuay heat pump systems usefixed orifice refrigerant control devices. The follow-ing procedure has been developed for this type ofrefrigerant control device.

1. With both base valves fully open, connect a set of servicegages to the base valves’ service ports, being careful topurge the lines.

2. Allow the system to operate at least 10 minutes or until thepressures stabilizes.

3. Temporarily install a thermometer on the suction (large)line near the condensing unit base valve. Make sure thatthere is good contact between the thermometer and therefrigerant line and wrap the thermometer and line withinsulating tape to provide accurate readings.

4. Determine the systems superheat as follows:

a. Read the system’s suction pressure.b. Using Table 6, determine the system’s saturated suction

temperature.c. Read the suction line temperature.d. The system’s superheat = the suction line temperature -

the saturated liquid temperature.

Table 6: Saturated Suction Pressure (R-22)

5. Adjust the charge as necessary by adding charge to lowerthe superheat or bleeding the charge to raise the superheat.

Table 7: System Superheater.

Expansion Valve System-Subcooling Charge Method1. Fully open both base valves.

2. Connect service gauge manifold to base-valve service partsverify that lines are purged. Run system at least 10 min-utes to allow pressure to stabalize.

3. Temporarily install the thermometer to liquid (small) linenear the condensing unit. Be sure that the contact betweenthermometer and line is good. Wrap the thermometer withinsulating material to provide an accurate reading.

4. Referring to Table 8, adjust charge to obtain a temperature12-15°F below the saturated liquid temperature.

Example:If liquid pressure is 260 psig, refer to Table 8. 260 psig = 120°saturated temperature. Subtract the liquid line temperatureobtained from thermostat connected to the liquid line. The liq-uid line temperature must be 12° - 15° cooler than the refriger-ation saturation temperature. If the liquid line temperature iswarmer than 12° - 15°, add charge to decrease. If the tempera-ture of the liquid line is cooler than 12° - 15°, recover chargefrom the system.

LINE O.D. (IN) LIQUID LINE SUCTION LINE1/4 0.223/8 0.581/2 1.145/8 1.86 0.043/4 0.067/8 0.08

1 1/8 0.151 3/8 0.22

SUCTION PRESSURE PSIGSATURATED SUCTION

TEMPERATURE oF50 2653 2855 3058 3261 3463 3666 3869 4072 4275 4478 4681 48

AMBIENT CONDENSER INLET TEMPERATURE oF DB

RETURN AIR TEMPERATURE oF DB65 70 75 80 85

100 5 595 5 7 990 7 12 1885 5 10 17 2080 5 12 21 2675 5 10 17 25 2970 5 14 20 28 3265 13 19 26 32 3560 17 25 30 33 37

CCAUTIONRemove the service gauge set from the lines care-fully. Escaping liquid refrigerant can cause burns.

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Table 8: Saturated Liquid Temperature

HEAT PUMP - HEATING CYCLEAs in the cooling mode, the proper method of verifying thatthe system is properly charged is by weight, with the additionalcharge adustments for line size, line length, and other systemcomponents.Hot Gas MethodThe following procedure can be employed as a method tocheck for system charge in the heating mode by measuring thehot discharge gas at the compressor.1. Allow the system to operate at least 20 minutes.

2. Attach and insulate an electronic thermometer probe to thevapor service valve (large line) at the base valve. NOTE - Make sure that the probe is well insulated fromthe outdoor air.

3. Allow the system to operate at least 10 minutes. Then, usean accurate electronic thermometer to measure the temper-ature of the discharge gas at the probe.

4. Using the electronic thermostat, measure the outdoor ambi-ent temperature.

5. For verification, the temperature measured on the hot gasline should be equal to the outdoor ambient temperatureplus 110°F +/- 4°F. (e.g: if the Outdoor Ambient is 45°F,then the temperature measured by the thermometer probeshould be 155°F for a system that is properly charged). Ifthe temperature measured by the thermometer’s probe ishigher than the outdoor ambient plus 110°F, the systemcharge should be adjusted by adding refrigerant to lowerthe temperature. If the temperature measured is lower thanthe outdoor ambient plus 110°F, the system charge shouldbe adjusted by recovering charge to raise the temperature

Note: When adjusting the charge in this manner, allow thesystem to operate for at least 10 minutes before tak-ing the next temperature reading.

STARTUP PROCEDURE AND CHECK LIST

1. Set first-stage thermostat heat anticipator to .12 and turnthermostat system switch to “COOL” and fan switch to“AUTO”.

2. Turn cooling temperature setting as high as it will go.

3. Inspect all registers and set them to the normal open posi-tion.

4. Turn on the unit electrical supply at the fused disconnectswitch, both for the indoor unit and the outdoor unit.

5. Turn the fan switch to the “ON” position. The blowershould operate 10 to 15 seconds later.

6. Turn the fan switch to the “AUTO” position. The blowershould stop 90 seconds later.

Note: If outdoor temperature is below 55°F, proceed tostep 9. Do not check the cooling mode.

7. Slowly lower the cooling temperature until the first mer-cury bulb makes contact. The compressor, indoor blower,and outdoor fan should now be running. Verify cool air isbeing supplied by the unit.

8. Turn the system switch to “HEAT” and the fan switch to“AUTO”.

9. Slowly raise the heating temperature setting. After the heat-ing first-stage mercury bulb (upper) makes contact, stopmoving the lever. The compressor, indoor blower and out-door fan should now be running. After giving the unit timeto settle out, verify heated air is being supplied by theindoor unit.

10.If the outdoor ambient is above 70°F, the compressor maytrip on internal overload.

11. In the event that the outdoor ambient temperature is toohigh to allow a thorough heating cycle check, postpone thetest until conditions are more suitable. However, do not failto perform a through heating cycle check.

12.If the unit operates properly on the heating cycle, raise theheating temperature until the heating second-stage mercurybulb (lower) makes contact.

13.Supplementary resistance heat, if installed, should nowcome on. Verify it is operating correctly. If outdoor thermo-stats are installed, the outdoor ambient temperature must bebelow the set point of these thermostats for heaters to oper-ate. It may be necessary to jumper these thermostats tocheck heater operation if outdoor ambient temperature ismild.

14.For thermostats with an emergency heat switch, return toStep #9. The emergency heat switch is located at the bot-tom of the thermostat. Move this switch to emergency heat.The heat pump will stop, the indoor blower will continue torun, all heaters will come on and the thermostat emergencyheat light will come on.

15.If checking the unit on the heating cycle in the winter(when the outdoor coil is cold enough to actuate the defrostcontrol), observe at least one defrost cycle to verify that theunit defrosts properly.

16.Check to see if all supply and return air grilles are adjustedand the air distribution system is balanced for the best com-promise between heating and cooling.

17.Check for air leaks in the ductwork.

LIQUID PRESSURE PSIG SATURATED TEMPERATURE oF200 102210 105220 108230 111240 114250 117260 120270 123280 126290 128300 131

CCAUTIONTurn off power at all disconnects.

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18.Verify that the heat pump is free of “rattles” and the tubingin the unit is free from excessive vibration. Also verify thattubes or lines are not rubbing against each other, sheetmetal surfaces or edges. If so, correct the issue.

19.Set the thermostat at the appropriate setting for cooling andheating or automatic changeover for normal use.

20.Instruct the owner on the unit operation, filter servicing,correct thermostat operation, etc. The foregoing “Start-upProcedure and Check List” is recommended to serve as anindication that the heat pump system will operate normally.

OPERATION - DEFROST CONTROLTimingWhen operating, the power to the circuit board is controlled bya temperature sensor that is clamped to a return bend on theoutdoor coil. Timing periods of 30, 60, or 90 minutes may beselected by connecting the circuit board jumper wire to 30, 60or 90 respectively. Accumulation of time for the selected tim-ing period begins when the sensor closes (approximately 28°F)and when the wall thermostat is calling for heat. At the end ofthe timing period, a defrost cycle will be initiated, provided thesensor remains closed. When the sensor opens (approximately65°F), the defrost cycle is terminated. If the defrost cycle is notterminated due to the sensor temperature, a 10 minute overrideinterrupts the defrost period.

Field Testing / Trouble ShootingA. Run unit in heat mode.

B. Check unit for proper charge. Note: Bands of frost indicatelow refrigerant charge

C. Shut off power to unit.

D. Disconnect outdoor fan by removing the purple lead from“DF2” on defrost control.

E. Restart unit and allow frost to accumulate.

F. After a few minutes of operation, the defrost thermostatshould close. To verify this, check for 24 volts between“DFT” and “C” on the board. If the temperature at the ther-mostat is less than 28°F and the thermostat is open, replacethe thermostat as it is defective.

G. When the defrost thermostat has closed, short the “test”pins on the board until the reversing valve shifts, indicatingdefrost. This could take up to 21 seconds depending onwhat timing period the board is set on. After defrost initia-tion, the short must instantly be removed or the defrostperiod will only last 2.3 seconds.

H. After the defrost has terminated, check the defrost thermo-stat for 24 volts between “DFT” and “C”. The readingshould indicate 0 volts (open sensor).

I. Shut off power to unit.

J. Replace the outdoor fan motor lead and turn on the power.

General Explanation and Guidance The heat pump operates similar to a summer air conditioningunit when it is on the cooling cycle. Therefore, all of the chartsand data for service that apply to summer air conditioning also

apply to the heat pump when it is on the cooling cycle. Mostapply to the heating cycle, except that “condenser” becomes“evaporator”, “evaporator” becomes “condenser” and “cool-ing” becomes “heating”. When the heat pump is on the heat-ing cycle, it is necessary to redirect the refrigerant flowthrough the refrigerant circuit external to the compressor. Thisis accomplished with a reversing valve. Thus, the hot dis-charge vapor from the compressor is directed to the inside coil(evaporator on the cooling cycle) where the heat is removed,and the vapor condenses into liquid. It then goes through acapillary tube, or expansion valve, to the outside coil (con-denser on the cooling cycle) where the liquid is evaporated,and vapor goes to the compressor.

When the solenoid valve is operated either from heating tocooling or vice versa, it moves the pilot valve, thus puttingsuction pressure (low pressure) on one side of the piston of thereversing valve. Because discharge pressure (high pressure) ison the other side of the piston, the piston slides to the low pres-sure side and reverses the flow of the refrigerant in the circuit.

The following figures show a schematic of a heat pump on thecooling cycle and the heating cycle.

Figure 4. Heat Pump Refrigeration Circuit

In addition to a reversing valve, a heat pump is equipped withan expansion device and check valve for the inside coil, andsimilar equipment for the outside coil. It is also provided witha defrost control system.

IM-801 Page 13

The expansion device performs the same function on the heat-ing cycle as on the cooling cycle. The check valves arerequired due to the reverse flow of refrigerant when changingfrom cooling to heating or vice versa.When the heat pump is on the heating cycle, at which time theoutdoor coil is functioning as an evaporator, the temperature ofthe refrigerant in the outdoor coil must be below the tempera-ture of the outdoor air in order for the refrigerant in the outdoorcoil to extract heat from the air. Thus, the greater the differencein outdoor temperature and outdoor coil temperature, thegreater the heating capacity of the heat pump. Since this ischaracteristic of heat pumps, it is good practice to provide sup-plementary heat for all heat pump installations in areas wherethe temperature drops below 45°F. It is also good practice toprovide sufficient supplementary heat to handle the entire heat-ing requirements in case of a of heat pump failure (e.g. a com-pressor failure, refrigerant leak, etc).Because the temperature of the liquid refrigerant in the outdoorcoil during the heating cycle is generally below the freezingpoint, frost forms on the surfaces of the outdoor coil under cer-tain weather conditions of temperature and relative humidity.Therefore, it is necessary to reverse the flow of refrigerant toprovide hot gas in the outdoor coil and melt the frost accumu-lation. This is accomplished by reversing the heat pump to thecooling cycle. At the same time, the outdoor fan stops to has-ten the temperature rise of the outdoor coil and lessen the timerequired for defrosting. The indoor blower continues to runand the supplementary heaters are energized.

MAINTENANCEGeneralOutdoor units do not require a planned maintenance programunder normal operating conditions. However, not less thanonce each cooling season, the unit should be inspected and, ifnecessary, cleaned. Particular attention should be given to theair inlet side of the outdoor coil to verify that leaves, grass,etc., are not being drawn into the unit. Restricting air flowacross the coil will result in loss of system capacity, high oper-ating pressures and excessive operating costs. If the outdoorunit is installed adjacent to a grassy area, lawn mowers shouldbe routed so the discharge of the mower will be directed awayfrom the unit. Air filters must be installed in the system atsome point upstream to the indoor coil. Inspect and, if neces-sary, replace and/or clean air filters at least once a month.If disposable filters are used, an adequate supply of clean,unused filters of the correct size should be available.

Permanent type filters may be vacuumed and/or washed; butthey should not be reinstalled until thoroughly dry. Most air fil-ters are marked to indicate the direction of airflow and thisshould be carefully noted when they are being installed.

The blower and motor bearings are permanently lubricated anddo not require additional lubrication.The owner should have at least one set of replacement fuses ofthe size supplied with the original equipment.

Common Causes of Unsatisfactory Operation ofHeat Pumps on the Heating CycleA. Dirty filters or inadequate air volume through the

indoor coil. When the heat pump is on the heating cycle,the indoor coil is functioning as a condenser. Therefore, thefilters must always be clean and sufficient air volume mustpass through the indoor coil to prevent excessive dischargepressure and high-pressure cutout.

B. Outside air into return duct. Cold outside air should notbe introduced in the return duct close enough to the indoorcoil to reduce temperature of the air entering the coil below65°F during the heating cycle. Air below this temperaturewill cause low discharge pressure, low suction pressure andexcessive defrost cycling that will result in low heating out-put. It may also cause false defrosting.

C. Undercharge. Undercharge on the heating cycle will causelow discharge pressure, resulting in low suction pressureand frost accumulation on the lower part of the outdoorcoil.

D. Poor “terminating” defrost thermostat contact. Thedefrost thermostat must make good thermal contact on thereturn bend. Otherwise, it may not terminate the defrostcycle quickly enough to prevent the unit from cutting outon high discharge pressure during the defrost cycle.

E. Causes of Malfunctioning Reversing Valve: 1. Solenoid not energized. In order to determine if the

solenoid is energized, touch the nut that holds the sole-noid cover in place with a screwdriver. If the nut mag-netically holds the screwdriver in the Cooling mode,the solenoid is energized.

2. No voltage to solenoid. Check the voltage and if thereis no voltage, check the wiring circuit.

3. Valve will not shift:a. Undercharged: check for leaks.b Valve Body Damaged: Replace valve.c. Unit Properly Charged: If it is on the heating

cycle, raise discharge pressure by restricting air-flow through the indoor coil. If the valve doesnot shift, tap it lightly on both ends with a screw-driver handle.

CCAUTIONEquipment should never be operated without filters.

CCAUTIONNever turn a dirty filter to allow airflow in the oppo-site direction.

CWARNINGDo not replace fuses with sizes other than those supplied. Improper current protection can cause equipment damage, severe personal injury or death.

Page 14 IM-801

WIRING DIAGRAM

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IM-801 Page 15

THERMOSTAT DIAGRAM

Heat Pump

C W2 O Y R RCY O W2 G E

ConventionalRoom Thermostat

BLW

ORY

R

BL

W

OR

Y

RR

GR

W

BRBL

BL

#18 GA. 5 Wire

#18 GA. 7 Wire

Pink

Outdoor Thermostat(optional) Make On Fall

#18GA. 6 Wire Needed When Outdoor Thermostat Is Used

SAH018 to 060SYSTEM COMPOSITE DIAGRAM

18-6010 KW & BELOW

BL

BR

C W2 O Y R RCY O W2 G E

#18 GA. 5 Wire

#18 GA. 7 WireConventional

Room ThermostatHeat Pump

SAH018 to 060SYSTEM COMPOSITE DIAGRAM

18-6010 KW & BELOW

RR

RY

ORW

BL

BL

W

OR

Y

W

GR

EHR

OT1

OT2

#18GA. 7 Wire Needed When 2 Outdoor Thermostat Are Used

Pink

AR Indoor Unit

Note

SeeNote 3

SeeNote 2

SeeNote 3

NOTES:1. Outdoor Thermostat (OT1) should be the first to close and the first to open.2. Install jumper if Outdoor Thermostat (OT2) is not used. 3. Remove wire when using Outdoor Thermostat. #18 Ga. 7 wire needed when (2) OTs are used.

NOMENCLATURE :OT - Outdoor Thermostat (Optional)MOF - Make On FallEHR - Emergency Heat Relay (Optional)

COLOR CODESR - Red OR - OrangeY - Yellow W - WhiteBL - Blue G- GreenBR - Brown

1 2

34

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