LG AR-DR12-05A Installation And Operation Manual page 57

TROUBLESHOOTING - REFRIGERATION CIRCUIT
Symptom Possible Cause
Excessive load on evaporator coil.
Compressor is unloaded. (digital
scroll)
Expansion valve sensing bulb not
High suction
secured to suction line.
pressure
Thermostatic expansion valve.
Overfeeding.
Room load too large.
Overcharged.
Thermal expansion valve setting.
Air inlet to condenser dirty or
obstructed.
Condenser fan motor defective.
Too much refrigerant.
High discharge
Non-condensable in system.
pressure
Dirty condenser coil.
Condenser fan not running or running
backwards.
High load conditions.
Refrigerant undercharge/loss of
refrigerant charge.
Blower running backward.
Low entering air temperature. (Low
load conditions).
Refrigerant leak.
Low suction
Evaporator dirty or iced-up, or airflow
pressure
restricted.
Plugged liquid line filter-drier.
Improper hot gas bypass setting.
Expansion valve defective, superheat
too high or valve too small.
Moisture in system, check sight
glass.
Check for high entering wet bulb temperature, check for excessive air flow.
Check digital scroll controller signal and solenoid valve.
Check the thermal expansion valve, ensure bulb is insulated. Check superheat. If
superheat is high, then valve is choking refrigerant flow.
• Check bulb for contact.
• Adjust valve for superheat ~10°F.
• Replace valve power head or valve.
Check bulb location and clamping. Adjust superheat. Replace expansion valve power
head.
Reduce the load or add more equipment.
Check pressures and subcooling.
Check thermal expansion setting and calibrate superheat / subcooling.
Check for proper clearances and possible air recirculating. Clean coil.
Check condenser fan motor.
Check subcooling. Remove excess refrigerant.
Remove non-condensable from system.
Clean condenser coil.
Check electrical circuit and fuse. Check fan cycling controls.
Add more equipment or reduce load.
Check pressures and subcooling.
Confirm blower rotation. If reversed, interchange any two wires from 3-phase
disconnect.
Check entering air wet bulb conditions.
Check system for leaks. Repair leaks and add refrigerant.
Clean the coil. Check fan operation. Check airflow.
Replace filter-drier, check psi across filter.
Check setting and correct as required.
Adjust valve for proper superheat or replace the expansion valve if too small or
defective.
Reclaim refrigerant, check for leaks, recharge.
Due to our policy of continuous product innovation, some specifications may change without notification.
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Corrective Action
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