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
µ
P-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
