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4 INSTALLATION OF REMOTE OUTDOOR HEAT EXCHANGER
Air cooled condenser and fluid coolers have individual User Manuals which should be referred to for
more complete details.
5 CHARGING
General charging guidelines:
• Check the CRAC unit nameplate for refrigerant type (R-410A or R0407C) to be used
• Unit control configurations differ depending on refrigerant type
• Refrigerant charging requires the unit to be operational
• Calculate the amount of charge for the system
• Care must be taken to prevent over charging the system
• It is recommended to charge the unit using the manual override switches
• The return air temperature to the unit being charged must be stable and must be maintained
greater than 65°F (18°C)
• If this is not possible due to lack of heat load, then load banks must be used to offset the cooling
load during startup
5.1
Voltage Phase Check
5.1.1 Evaporator Power Phasing
Prior to charging, the correct voltage phasing should be checked on the indoor evaporator. EC plug
fans are not dependent on the input power phasing and will always operate in the proper direction.
The correct voltage phasing for the scroll compressors and forward-curved centrifugal blowers must
be checked. Both of these components are phase dependent and although our units are factory run
tested, it is important to make sure the rotation of these motors is correct in the field.
A quick and easy way to check the scroll compressor rotation on the evaporator section is to momentarily
energizing the manual switches on the Manual Override Switch board located next to the microprocessor
control module. Switching the manual switches to the ON position will disable the automatic control but
leave the safety switches functional.
Slide the Cool 1 and/or 2 switch to the ON position, observe the compressor operation for a short period
of time then slide the switch back to the OFF position. An out of phase compressor will draw relatively
low amps and both suction and discharge pressures will remain nearly equal. Reverse any two of the
three line voltage wires at the line voltage field connection point to change the compressor rotation.
The gForce units include backward curve plenum fans with electronically commutated (EC) motor as
a standard feature. The EC motors are phase independent therefore fan rotation will always be in the
correct direction.
Although the scroll compressor is phase dependent, units shipped from the factory are run tested
ensuring compressor rotation is consistent with the evaporator fan motor. However, a field change-out
of the compressor may require checking proper phase.
5.1.2 Remote Heat Exchanger Fan Motor Phasing
The gForce remote heat exchanger (GHRC) (air cooled or dry coolers) are three phase and the individual
axial fans with electronically commutated (EC) motors are three phase and will only run in one direction.
Check operation by placing a momentary jumper across low voltage terminals # 39 and # 40 which will
energize the control circuit.
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