IPAC Air Handling Units
Short-form version - extracted from Section 2 of the Installation, Operation and Maintenance Manual
Technical Product Guide
IPAC(Invicta Precision Air Control)
15 to 120 kW, Upflow, Downflow,
Direct Expansion, Water-Cooled Direct Expansion, Chilled Water
Issue 3.2 : November 2004
Heading PageIntroduction 4
Application 4Duty Range 4Temperature Control 4Humidity Control 4
Reliability 4Serviceability 5Unit Identification 5Temperature Control 5Cooling Process 5
Air-cooled Direct Expansion (DX) System 15
Water-cooled DX System 16Chilled Water Cooling System 17Economy Cooling Options 18
Humidity Control 19Dehumidification 19
Hot Gas Reheat 19
Network Control System 19Main Components 19
Unit Casing 22Finish 22Supply Air Fan(s) 22Air Filters 22Differential Pressure Switches 22Cooling Coil 23Condensate Drip Tray 23Eaton-Williams InvictaNET AHU Controller 23Electrical connections 23Volt-free Alarm Contacts 23Bottom Connections 23Compressor 23Filter / Drier 24Thermostatic Expansion Valve 24Moisture Indicating Sight Glass 24Evacuation and Refrigerant Charging Valves 24Pressure Safety Devices 24Modulating Flow Control Valve and Actuator 24Key Operated Cam-lock Removable Doors 25Airflow Failure Detection 25Cardboard Sleeve / Pallet Delivery Protection 25Contactors, MCBs and MPCBs 25Internal Unit Isolator 25Interconnecting wiring loom 25Integrated Water-Cooled Condenser 25
Features and Options 25Phase-failure relay 25Control panel cover 25Fresh Air Control 25Fresh Air Control, Including Smoke Detection 26Door-interlocked isolator 26Mains filter kit 26In-Room Remote Sensors 26
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Duct Remote Sensors 26Water Detection Tape 26Audible Alarm 26Alternate Display Languages 26ModBus Network Interface 26Trend Controller 26Trend Network Interface 26Heating Process 26Electric Heating 26Low Pressure Hot Water Heating System 27LPHW Heating Coil 28Capacity Control Hot Gas Injection System 282 Way or 3 Way Control Valve 28Liquid Receiver 28Oil Separator 28Compressor Acoustic Jacket 28Compressor Discharge Non-return Valve 28Split Coil Rapid Dehumidification 28Pressure Relief 28Water System Isolating Gate Valves 29Commissioning Set 29Flexible duct connectors (upflow units only) 29Back-draught dampers (upflow units only) 29Airflow Options 29Humidifier 2920% - 100% Proportional Output Humidifier 30Alarm Diagnostics Tools in Controller 30Different Bottles for Varying Water Qualities 30Remote Vapac Options 30Second Unit OEM Option 30Rear Cosmetic Cover Panel 30Multi-speed motors 30Side Gland Plates 30Stainless Steel Drip Tray 305 to 10 % fresh air intake, including volume damper control 30Anti-vibration mountings 30Dual Pulley Drives 30Low Display Mounting 30Lifting Channels 30Condensate Pump 30Class 1, energy-efficient motors 31Customised Colours 31Pipework 31Flood Detection 31Electrical Equipment 31Air Movement Options 32Emergency Shutdown 33Fire Shutdown 33
Ancillary Options 33Adjustable Feet 33Floor Support Angles 34Open frame 34Open Frame Base and Scoop 34Enclosed Section (for ducting, etc.) 34Turning Section (inc. double-deflection grilles) 34Fresh Air Modulating Section 35High-efficiency Filter Section 35
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IntroductionThis section provides information about the main components ofInvicta Precision Air Control (IPAC) standard range air handlingunits (AHUs).
ApplicationIPAC units are designed as a modular range of both upflow anddownflow, floor-standing, air handling units for operation atroom temperatures from 18 C to 30 C as standard. Factory-added options can enable operation outside this range.These units provide highly reliable air handling systems forspace-cooling, where the air must be conditioned to be:
Temperature controlled (heating is optional)
Humidity controlled (optional)
Filtered clean of particulates
Duty RangeBasic duty sizes for standard units in the IPAC range are asshown in Table 1-1, which also identifies which are single ortwin module units, together with matching condenser options.Twin module units can be positioned separately, offeringflexibility according to installation requirements; refer to Fig. 1-3for dimensions and weight data.
By offering a selection of various combinations of unitconfiguration, duty requirements can be matched accurately.The various standard unit configurations available are asillustrated in Fig. 1-3, while airflow path configurations areillustrated in Fig. 1-11.Units are manufactured with either upflow or downflow airdirection, to provide optimum comfort levels.
For a dual module pair, the electrical section of the larger unitcontains the controls and switchgear for control of the other.All dual module interconnecting wiring is made to numberedterminal rails in each unit for easy connection at site. To ease installation, an interconnecting wiring loom is availableas an optional extra.IPAC air handling units are designed for indoor installation only.Units can either be mounted within the space to be conditioned,or mounted elsewhere with air ducted to the room.As well as the standard unit configurations, a variety ofcustomising options can be factory-fitted or site-fitted, toprovide a system that precisely matches user requirements.
Temperature ControlTemperature can be precisely controlled, with cooling providedby the cooling coil(s).Where heating is required, mutli-stage electrical heating, or lowpressure hot water (LPHW) are available as options.Air temperature is controlled by two PID (Proportional Integraland Derivative) algorithms, one for heating, the other forcooling.Each algorithm includes the same adjustable dead band, whichequally spans each side of the room temperature set point.If I (Integral) and D (Derivitive) values are zero, control isproportional only.Proportional units are in C.
Humidity ControlWhere dehumidification is required, a cooling coil is operatedbelow the dew point of the air to condense and remove watercontent from the air.To ensure optimum temperature control in conjunction withdehumidification, the options of hot gas or electric reheat areavailable.Where humidification is required, a factory-fitted Vapac
humidifier unit is available as an option. This is a proportional-output humidifier that produces clean, sterile steam, that isentrained into the airflow to increase its humidity.The humidifier responds to a changing demand, using the waterlevel (WL) system of modulation. Output is varied by increasingor decreasing the level of water in the cylinder. Air humidity is similarly is controlled by two PID algorithms, onefor humidification, the other for dehumidification.Each algorithm includes the same adjustable dead band, whichequally spans each side of the room humidity set point.If I (Integral) and D (Derivitive) values are zero, control isproportional only. Proportional units are in % RH.
ReliabilityIPAC units are designed for high reliability with a calculatedmean-time between failure of not less than four years, providedthat routine maintenance procedures are carried out atprescribed intervals.
Table 1-1 : Duty range and matching air-cooled condensers
UNITSINGLE / TWINMODULE UNIT
Matching Air-cooledCondenser Models
15 IPAC 15-1 Single ICV1-18P -22 IPAC 22-1 Single ICV1-40P -30 IPAC 30-1 Single ICV2-40P -30 IPAC 30-2 Twin ICV1-18P ICV1-18P40 IPAC 40-1 Single ICV2-70P -45 IPAC 45-2 Twin ICV2-40P ICV1-18P50 IPAC 50-1 Single ICV3-70P -55 IPAC 55-2 Twin ICV2-70P ICV1-18P60 IPAC 60-1 Single ICV3-70P -60 IPAC 60-2 Twin ICV2-40P ICV2-40P70 IPAC 70-2 Twin ICV2-70P ICV2-40P80 IPAC 80-2 Twin ICV2-70P ICV2-70P90 IPAC 90-2 Twin ICV3-70P ICV2-70P
100 IPAC 100-2 Twin ICV3-70P ICV3-70P110 IPAC 110-2 Twin ICV3-70P ICV3-70P120 IPAC 120-2 Twin ICV3-70P ICV3-70P
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ServiceabilityThe maximum time required replacing Service Items, andreturning the unit to operational condition is approximately 1hour, excluding refrigeration circuit items, provided of course,that recommended service parts are held ready to use.For details of recommended service parts for each unit, togetherwith contact and ordering details, please contact the Eaton-Williams Head Office.
Unit IdentificationVital data on a unit can be obtained from the serial numberplate, which can be found inside the cabinet, just below theelectrical chassis on the left hand side.
The following data is normally shown on the serial number plate:
Product - EW code number.Cooling Capacity - design cooling capacity in kW.Electrical Supply - for which the unit is rated.Wiring Diagram - relevant to the unit.Power - consumption at maximum load in kVa.Serial Number - of the unit.Short Circuit Capacity - in kA.Maximum Start Current - consumption in Amps.Refrigerant - type and quantity in kg, to be filled when
known; i.e on completion of commissioning.Full Load Current - consumption in Amps.
Temperature ControlThe temperature of supply air passing through the unit ismonitored by an Eaton-Williams InvictaNET AHU controller,which applies cooling or heating (optional) control strategy tocorrect and maintain room air temperature at a predeterminedset point.
The Cooling Process is described below. The Humidity Control is described on page 19.
The air passage through the unit is the same, whether in heatingor cooling mode.
Cooling ProcessThe cooling process is used for air cooling and/ordehumidification and is achieved by one of three types of cool