LG AR-DR12-05A Installation And Operation Manual page 56

TROUBLESHOOTING - REFRIGERATION CIRCUIT
Symptom
Refrigerant overcharge.
Condenser fan motor defective.
Compressor starts
Condenser coil inlet obstructed or dirty.
but cuts out on high
pressure switch
Air or non-condensables in system.
Defective high pressure switch.
High pressure
activates at 600 PSIG
Restriction in discharge or liquid line.
Condensing fan relay not pulling in.
Low voltage.
Sustained high discharge pressure.
High suction and discharge pressures.
Defective compressor overload.
Compressor cuts out
on thermal overload Improper refrigerant charge.
Improperly wired.
Loose wiring.
Defective start relay.
Motor windings damaged.
Improperly wired.
Low line voltage.
Loose wiring.
Compressor hums,
but will not start
Defective start relay.
Motor winding damaged.
Internal compressor mechanical
damage.
Refrigerant overcharge.
Liquid floodback.
Tubing rattle.
Compressor noisy or
vibrating
Scroll compressor rotating in reverse.
(3-phase)
Damaged compressor.
Improper mounting on unit base.
56
Possible Cause
Check pressures, charge by subcooling.
Check fan motor.
Check coil and clearances. Clean coil if necessary.
Check high side equalized pressures, check thermal expansion valves.
Replace
Check refrigerant line pressures, check thermal expansion valves, replace any
defective component.
Replace.
Check voltage.
Check running amperage and conditions described under "low suction
pressure" symptoms.
Check thermal expansion valve setting, check for air in system. Check air
conditions and cfm.
If compressor is hot, allow compressor to cool for two hours. Recheck for open
circuit.
Check subcooling.
Review wiring schematics.
Check all connections.
Replace relay.
Verify amp draw.
Review wiring schematics.
Check voltage.
Check all connections.
Replace relay.
Verify amp draws. Replace compressor if necessary.
Replace.
Check pressures and subcooling.
Check thermal expansion valve setting. Check for refrigerant overcharge.
Dampen tubing vibration by taping or clamping. Carefully bend tubing away
from contact where possible.
Check high and low side pressures during operation to confirm. Rewire for
opposite rotation.
Replace the compressor.
Check that compressor is properly isolated and mounting bolts are tight.
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Corrective Action