Troubleshooting - Refrigeration Circuit - LG AR-DR12-05A Installation And Operation Manual

TROUBLESHOOTING - REFRIGERATION CIRCUIT

Before any components are changed on the refrigeration system, the cause of the failure must be identified.
Further problems will exist unless the true cause or problem is identified and corrected.
Do not release refrigerant to the atmosphere.
If required service procedures include the adding or removing of refrigerant, the service technician must comply with all federal, state and local laws.
The procedures discussed in this manual should only be performed by a qualified EPA Certified Technician.
This unit is equipped with a phase loss/phase reversal control. If system does not start, check phase of electrical supply.
The first step in troubleshooting a refrigeration circuit is to examine the microprocessor controller and digital scroll compressor controller (if
present) and see if there is a fault code. The next step is to check airflow conditions (e.g. improper ductwork, atypical wet bulb / dry bulb,
etc.). After these steps have been eliminated, proceed with troubleshooting by following this guide.
Symptom
Open disconnect switch or circuit
breaker.
Compressor contactor not closing.
Blown fuse or tripped breaker.
Low line voltage.
Compressor motor protector open.
Compressor will not run
or does not start
Compressor defective.
High pressure switch open or
defective.
Low pressure switch open or
defective.
Open room thermostat or control.
(No cooling required).
Loose wiring.
Low or loss of refrigerant charge.
Compressor starts
but cuts out on low
Airflow restricted.
pressure
Restriction in refrigerant line.
Low pressure switch
activates at 50 PSIG
Defective low pressure switch.
Possible Cause
Close switch and/or breaker.
Check voltage to contactor coil, transformer, slave relay, system. Replace parts
as necessary.
Check for reason and repair. Replace fuse after correcting problem.
Check line voltage. If more than 10% from compressor marking, correcting is
necessary.
Motor thermal protector automatically resets. Allow time (2 hours) for compressor
to cool down so protector will reset. Restart and check for reason overheat
occurred.
Check motor for open circuit, short circuit, grounded windings, or burn out.
Compressor may be seized; check refrigerant. If necessary, replace compressor.
If manual reset (high pressure), reset switch. (Switch opens at 610 psi and will
not reset above 420 psi for R-410A). Replace if defective.
See switch label for set point.
Check room temperature. If temperature is proper, wait for thermostat to close.
Check all wire terminals and tighten as necessary.
Check refrigerant pressures and temperatures (subcooling.)
Check for dirty evaporator coil, dirty filters, dampers closed, iced evaporator coil,
improper belt, check motor amps, check duct design.
Check refrigerant pressures, look for frosted tubing and components indicating a
restriction. Check pressure drop across the filter drier.
Replace.
Due to our policy of continuous product innovation, some specifications may change without notification.
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Corrective Action
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