CSR-20 & CSR-40, September 1999
Mechanical Diagnosis 8-3
Condition Possible Cause Remedy
Compressor contactor Low line voltage Increase line voltage to at least 90% of
burned out compressor motor rating
Excessive line voltage Reduce line voltage to at least 110% of
compressor motor rating
Short cycling Eliminate cause of short cycling
Unit short cycles Defective controller Check controller with µP-D Microprocessor
Tester (see Diagnosis Manual, TK 41230)
Refrigerant overcharge or high Check for restricted filter drier or high side,
side restriction causing cycling and refrigerant overcharge
on high pressure cutout
Inefficient condenser operation Check condenser airflow, condenser
causing cycling on high pressure fan motor, condenser fan grille, condenser
cutout fan pressure switch, water pressure switch
(option), water flow rate (option) and \
water-cooled condenser-receiver tank
(option)
Noisy compressor Loose mounting bolts Tighten mounting bolts
Oil slugging or refrigerant flooding Perform Full Pretrip Test to check
back refrigerant charge. Check expansion valve
adjustment. Check compressor for
compressor oil.
Scroll rotating backwards Check phase correction system and check
unit wiring
Defective compressor Repair or replace compressor
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