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• If the TXV is in the close position, use a liquid charging adapter to break the vacuum at the
compressor suction and discharge Rotolock service valves with 90 PSIG (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
• See further instructions for the following options:
Section 5.8.2 Air-Cooled Split System Charging
Section 5.8.5 Flooded System Charging (Systems with Low Ambient Receiver Package)
Section 5.8.13 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.
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 5.8.2 Air-Cooled Split
System Charging or 5.8.5 Flooded System Charging (Systems with Low Ambient Receiver Package)
for initial charging.
Replace the fuses for the compressor 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 by
momentarily energizing the COOL 1 (circuit 1 compressor) under the Mini-dap4 Menu I – Manual
Control (Service Level). See Mini-dap4 User Manual instructions for details. As soon as the
compressors comes on, observe the compressor pressure difference for a few seconds and then turn
the Cool 1 OFF.
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