50
(621 kPa) of liquid refrigerant. A liquid charging adapter prevents liquid refrigerant from
entering the compressor.
• In some cases, the assistance of a refrigerant recovery machine may be necessary to
add the initial charge.
• Care must be taken to prevent from over charging the system and from liquid entering
the compressor and diluting the oil.
• 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.
• Start the unit up by using the setpoint under Menu B – Setpoints
• When charging, if the ambient is less than 60F (15.6C), some refrigerant will be
backed up in the condenser coil, causing the liquid level to drop. If head pressure is
below 320 PSIG (2206 kPa), block the condenser coil surface, or turn OFF the fans until
pressures rises above 380 PSIG (2620 kPa), while observing the receiver sight glass.
• Heat load is required when adjusting charge, use load banks to offset the cooling load.
• Suction pressure should be equal to 33F (0.56C) saturated temperature or greater
• If equipped with an EEV, when the system is properly charged the EEV valve should be
between 55% and 85% with an indoor temperature of 70°F (21.1C) to 74°F (23.3C).
• See further instructions for the following options:
Section
5.7.2 Air Cooled System Charging
Section
5.7.5 Flooded System Charging (Systems with Low Ambient Receiver Package)
Section
5.7.8 Water/Glycol-Cooled System Charging
Voltage Phase Check
Evaporator Power Phase Check
Prior to fully charging a unit, the correct voltage phasing should be checked on the indoor
evaporator. Electronically Commutated (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 80% of its refrigerant capacity by following the steps in Section
5.7.2
Air Cooled System Charging
or
5.7.8 Water/Glycol-Cooled System Charging
for initial charging.
Replace the fuses for each compressor (one at a time for dual circuit units) which were
removed in the above WARNING.
Fixed Speed Scroll Compressor Phase Check
Since the fixed speed, scroll compressors are phase dependent, the easiest way to check
proper phasing is to check the rotation of the fixed speed scroll compressor on the evaporator
section of dual circuit units by momentarily energizing the COOL 1 (circuit 1 compressor)
under the dap4 MENU I – MANUAL CONTROL (Service Level). See dap4 IOM instructions for
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