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5.3 Voltage Phase Check

5.3.1 Evaporator

Prior to fully charging a unit, the correct voltage phasing should be checked on the indoor evapora

tor. EC plug fans are not dependent on the input power phasing and will always operate in the proper

direction.

Before checking the fixed speed scroll compressor voltage phasing make sure that its circuit has been

charged with between 70% and 80% of its refrigerant capacity by following the steps in section 5.4.1

or 5.6.1 for initial charging. Since the scroll compressors are phase dependent, the easiest way to

check proper phasing is to check the rotation of the constant speed scroll compressor (if available)

on the evaporator section of dual circuit units by momentarily energizing the COOL 2 (constant speed

compressor) switch on the Manual Override Module located next to the microprocessor control mod

ule. Slide the Cool 2 switch to the ON position, observe the compressor operation for a few seconds,

and then slide the switch back to the OFF position. An out of phase constant speed scroll compressor

will draw relatively low amps and both suction and discharge pressures will remain nearly equal. If

necessary, reverse any two of the three input line voltage wires at the line voltage field connection

point to change the compressor rotation.
The gForce Ultra unit has a variable capacity compressor and an out of phase compressor will not

turn ON and the VFD will show an error message. On the Manual Override Module located next to

the microprocessor control module, slide the Cool 1 switch to the ON position, observe the VFD for an

error message then slide the switch back to the OFF position. If an error message is observed, reverse

any two of the three input line voltage wires at the line voltage field connection point to change the

compressor rotation.
Although constant speed scroll compressors are phase dependent, units shipped from the factory are

run tested, ensuring the compressor rotation is consistent with evaporator fan motor. However, a field

change-out of a compressor may require checking proper phase.
5.3.2 GHRC Air-Cooled Heat Exchanger
The GHRC air cooled heat exchanger are only offered in three phase voltages and the individual EC

fan motors will only operate in one direction so no additional phase verification is required.
The standard GHRC air-cooled condenser provided with Data Aire gForce Ultra equipment has a

modulating fan speed control feature built into the condenser control system and the fan motors.

The modulation speed of the fans is directly proportional to the compressor head pressure.

5.4 Air Cooled System Charging

WARNING:

The constant speed compressor (2nd stage) must be charged

before charging the variable speed compressor (1st stage) in a dual circuit

system.

NOTE:

Prior to refrigerant charging, a system vacuum and moisture removal

procedure must have been carried out. Refer to Section 5.2 for Triple Evacu-

ation prior to charging the system.

5.4.1 Constant Speed Compressor
See the tables for the appropriate charging