162 CG-SVX17D-EN
Maintenance
Refrigerant System Open Time
Model CGAM chillers use POE oil and therefore refrigerant system open time must be kept to a
minimum. The following procedure is recommended:
Leave a new compressor sealed until it is ready to be installed in the unit. Maximum system open
time is dependent upon ambient conditions, but do not exceed one hour open time.
Plug the open refrigerant line to minimize moisture absorption.
Always change the liquid line filter drier.
Evacuate the system to 500 microns or below.
Do not leave POE oil containers open to the atmosphere. Always keep them sealed.
Mechanical Compressor Failure
Replace the failed compressor(s) and change the oil in the remaining compressor(s) along with the
refrigerant system liquid line filter drier.
Electrical Compressor Failure
Replace the failed compressor and change the oil in the other compressor(s). Also add a suction
filter with cleanup cores and change the liquid line filter drier. Change filters and oil until the oil no
longer test acidic. See “Oil Testing.”
Compressor Motor Megging
Motor megging determines the electrical integrity of the compressor motor winding insulation.
Use a 500 volt megger. A less than 1 meg-ohm reading is acceptable and 1000 ohms per nameplate
volts is required to safely start the compressor.
Compressor Current Imbalance
Normal current imbalance could be 4 to 15 percent with balanced voltage due to motor design.
Each phase should register 0.3 to 1.0 ohms and each phase should be within 7 percent of the other
two phases. Phase to ground resistance must be infinity.
Note: Maximum allowable voltage imbalance is 2 percent.
Refrigerant Piping
The compressor suction and discharge lines are copper. In most instances, piping may be reused.
If piping is not reusable, order the correct service parts. Cut all tubing with a tubing cutter to prevent
copper filings from entering the system. Cut the tubing in a straight length of pipe after the
compressor connection has been unsweated. The line can then be reinstalled using a slip coupling
and brazing.
NOTICE:
Equipment Damage!
The compressor suction line configuration must not be changed in any way. Changing
compressor suction line configuration will compromise proper oil return to the compressor(s).
Compressor Electrical Terminal Box
Be sure to protect the terminal box when unbrazing or brazing compressor refrigerant piping
connections
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