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WARNING:
Pressure relief lines(s) must be vented to the atmosphere
per the latest edition of ASHRAE Standard 15 and/or any local building,
fire or mechanical codes. This applies to all units with either shell and
tube condensers or high-pressure relief valve options.
5.7.1.1.
Fixed Speed Compressor Pre-Charge
After the system has been properly evacuated. Calculate the proper charge by following the
steps and the data in the tables.
1. Select the model and refrigerant charge for evaporator and condenser in accordance with
the following table.
Weight of Refrigerant in Evaporator and
Condenser for Fixed Speed Compressor
Model
Starting Charge (lbs.)
GUAX-022XX
NA
GUAX-036XX
NA
GUAX-045XX
NA
GUAX-070XX
25
GUAX-091XX
32.5
GUAX-125XX
37.5
2. Add the amount of refrigerant needed for the evaporator and condenser plus the line-set
volume
5.4 Line Set Charge Calculations
3. Next connect the refrigerant tank to the refrigerant manifold gauge set and make sure the
manifold gauge set is properly purged.
4. From a vacuum, slowly open the high side liquid line valve on the refrigerant manifold gauge
to feed liquid refrigerant through the high side.
5. Add the calculated amount of refrigerant.
At this point there will be approximately 70-80% of the total charge in the system. It is likely that
more refrigerant will be required to complete the charging procedure. Close the valve on the
refrigerant manifold gauge set.
WARNING:
Before starting a compressor, the crankcase heater should
be energized for a minimum of 12 hours to reduce the possibility of liquid
slugging on start-up. Failure to energize the crankcase heater could
result in compressor damage. If the system is charged from a vacuum,
the preheating of the compressor is not necessary.