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I
TROUBLESHOOTING
COMPLAINT
7
Compressor does
not pump
8
Compressor will
not start
9
Compressor
starts but start
relay does not
drop out
10
Compressor
runs but cuts
out on
overload
SYMPTOMS
Minimal difference in pressure
between high side and low side
of system, when compressor
motor has power
Blown fuse or open disconnect
Tripped or damaged overload
Open pressure switch
Loose wires
Motor seized
High running current,
overload trips
Internal overload tripping
MUST WAIT 2-3 HOURS TO
CHECK IF IT WILL RESET
CAUSE
Broken suction valves
Broken discharge line
Internal pressure safety
valve stuck open
Short circuit or other
electrical failure
Overheating or overcurrent
Loss of refrigerant
charge
Vibration, bad crimping or
under-torque
Low oil level or phase
reversal
Incorrect wiring of start
components
Incorrect or defective
start relay
Incorrect or defective start
capacitor
Incorrect or defective
run capacitor
Low voltage
Excessive head pressure
due to dirty condenser
or lack of condenser air
or water flow
Low voltage or unbalanced
Faulty electrical connections
causing single phasing or
high current surges
Sticking start relay on
single phase machines
leaving start cap on circuit
SOLUTION
Change compressor
Change compressor
Check item 13 and change
compressor if
necessary
Check electrical circuit
and wiring
Wait 2-3 hours for overload
to reset and check
refrigerant charge or power
quality to the compressor
Check for leaks, repair
and recharge
Check terminals at
compressor, contactor and
wiring in general
Check oil level. Restart 3-ph
compressor by switching
2 phases; replace if it does not
restart
Check wiring
Confirm operation, model
and make
Confirm integrity and
specs, check if fitted with
discharge resistance
Confirm integrity and
specs
Fix undervoltage protection
See item 2 above
Fix undervoltage protection
Remake the connections
Replace relay and ensure start
cap is fitted with a discharge
resistance
17
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