LG Heat Pump Error Code P525

P525 indicates a reverse phase detection error on the outdoor unit. The heat pump has determined that the three-phase power supply is wired in an incorrect rotational sequence and has shut down to protect the compressor from running in the wrong direction. This is a protective lockout that requires a correction to the incoming power wiring or, less commonly, a control board repair.

No. The P525 lockout is a safety feature that prevents the compressor from operating with reversed phase rotation, which would cause immediate mechanical and refrigerant system damage. The unit will not run while this code is active, and you should not attempt to bypass the fault. Have the electrical supply corrected before restoring operation.

If the cause is incorrect wiring, repair costs are typically limited to an electrician or HVAC technician service call, which can range from $75 to $200 depending on your area. If the outdoor unit control board is found to be faulty, parts and labor costs can range from $300 to $700 or more. Most P525 cases are resolved with a simple wiring correction at no parts cost.

Correcting a reverse phase error involves working directly with three-phase electrical wiring, which is hazardous and typically requires a licensed electrician or HVAC technician. The fix itself, swapping two of the three line conductors, is straightforward once the correct phase order is confirmed with a phase rotation meter. Attempting this without proper electrical knowledge or tools is not recommended.

A simple power reset will not clear P525 if the underlying phase sequence issue is still present. The unit will re-detect the reverse phase condition on startup and immediately return to the fault state. The error will only clear once the phase wiring has been corrected and the unit can confirm proper phase rotation on the next power cycle.