LG Heat Pump Error Code CH73

CH73 indicates an AC input instantaneous overcurrent fault. The inverter PCB detected input current exceeding 48 amperes peak for at least 2 milliseconds, which is above the safe operating limit for the unit's Intelligent Power Module. The system shuts down automatically to prevent component damage. The fault can stem from refrigerant circuit issues, incorrect supply voltage, wiring problems, or a failing inverter PCB.

No, continued operation with a CH73 fault is not safe for the equipment. The overcurrent condition that triggers this code can permanently damage the Intelligent Power Module inside the inverter PCB and may also harm the compressor. The unit should remain off until a qualified technician has inspected the refrigerant circuit, electrical supply, wiring, and inverter board.

The first steps are to inspect the refrigerant circuit for pipe restrictions, blocked coils, EEV operation, and refrigerant overcharge, then verify that AC supply voltage at the unit is within 220V plus or minus 10% under load. After those are confirmed acceptable, the technician should inspect all AC input wiring and compressor wiring connections for looseness or damage. If all external conditions are normal, the inverter PCB assembly and its IPM should be evaluated.

Power cycling the unit may temporarily clear the CH73 code, but the fault will almost certainly return if the underlying cause is not corrected. Running the system repeatedly with an active overcurrent condition risks damaging the inverter PCB and compressor. It is strongly recommended to diagnose and correct the root cause before attempting to resume normal operation.

Repair cost depends entirely on the root cause. If the issue is a loose wire connection or an out-of-range refrigerant charge, costs are relatively low, typically in the range of $100 to $300 for a service call and labor. If an EEV replacement is needed, expect $200 to $500 in parts and labor. An inverter PCB replacement is the most expensive scenario, often ranging from $500 to $1,200 or more depending on the model and labor rates in your area.