LG HVAC Error Code 43

Error code 43 on an LG HVAC system means the high pressure switch has opened because refrigerant pressure on the high side of the system exceeded 600 PSI. This is a safety shutdown designed to protect the compressor from damage. The system will not restart normally until the pressure drops and the underlying cause is corrected.

No, you should not attempt to override or bypass the high pressure switch and continue operating the system. Pressures above 600 PSI can cause compressor failure, refrigerant line rupture, or fitting failures, all of which create safety hazards and very costly damage. Leave the system off until a technician has diagnosed and corrected the cause of the high pressure condition.

Repair costs vary widely depending on the cause. A condenser coil cleaning or fan blade replacement may cost between $100 and $300 in labor and parts. A failed condenser fan motor replacement typically runs $200 to $500. If refrigerant recovery, evacuation, and recharge are needed to correct an overcharge or remove non-condensables, expect costs in the $300 to $700 range. Compressor damage resulting from delayed repair can push costs significantly higher.

Some causes are accessible to a knowledgeable homeowner, such as clearing debris from around the outdoor unit or cleaning a visibly blocked condenser coil. However, diagnosing refrigerant overcharge, non-condensable gases, or a failed fan motor requires manifold gauges and electrical testing equipment. Working with refrigerant also requires EPA Section 608 certification in the United States, so a licensed HVAC technician is needed for those repairs.

Resetting the unit by cycling power may temporarily clear the fault if the high pressure switch resets automatically once pressure drops. However, the error code will return as soon as the system runs and pressure rises again, because the root cause has not been addressed. A reset is useful for confirming the fault is repeatable, but it is not a repair.