QBD COOLING SYSTEMS INC.
19
08 -2015
47-0480-192-N
14.
TROUBLESHOOTING
Malfunction
Possible Cause
Solution
Compressor will not
Start / no hum
•
Line disconnect switch open
•
Overload protector tripped
•
Controller stuck in open position
•
Controller off due to cold location
•
Wiring improper or loose
•
LP / HP switch failure
•
Controller failure
•
Main switch failure
•
Check power from outlet. Unplug and
•
plug in unit, replace
•
Fuse.
•
Replace the Overload
•
Repair or replace control
•
Re-assure the control probe location
•
Check wiring against diagram
•
Repair or replace the LP/HP switch
•
Replace the controller
•
Replace the switch
Compressor will not
start /hums but trips
on overload
•
Improper wiring
•
Low Voltage
•
Start capacitor defective
•
Relay failed
•
Compressor motor has a winding
open
•
Internal mechanical problem in
the compressor
•
Liquid refrigerant in compressor
•
Check wiring against diagram
•
Find out the reason & correct
•
Replace the start failed capacitor
•
Replace the failed relay
•
Replace compressor
•
Replace compressor
•
Repair or replace crankcase heater
and / or accumulator