LG Heat Pump Error Code P529

P529 is an outdoor unit compression rate 2 error on LG heat pumps. It indicates that the compressor is not maintaining the correct ratio between suction and discharge pressure during operation. The system triggers this code as a protective measure to prevent further mechanical damage. A refrigerant issue or compressor problem is the most common underlying cause.

No, you should not continue operating the heat pump while P529 is active. The system has detected that the compressor is not operating within its safe pressure parameters. Continued operation under these conditions can accelerate compressor wear and lead to complete compressor failure, which is significantly more costly to repair.

Repair costs vary widely depending on the cause. A refrigerant recharge or leak repair typically runs in the range of $150 to $600 depending on the refrigerant type and the extent of the leak. Expansion valve or filter drier replacement may cost $200 to $500 in parts and labor. Compressor replacement is the most expensive scenario, often ranging from $800 to $2,500 or more depending on the unit size and model.

Most of the root causes behind P529 require professional tools and EPA certification to address, particularly any work involving the refrigerant circuit. A homeowner can check the outdoor unit for obvious airflow obstructions, debris, or ice on the coil as a first step. However, pressure testing, refrigerant handling, and compressor diagnostics must be performed by a licensed HVAC technician.

A power reset may temporarily clear the P529 code, but if the underlying cause has not been corrected, the error will return once the system attempts to operate again. Resetting the unit without diagnosing the root cause risks further damage to the compressor. A proper diagnosis using manifold gauges and a system inspection should be completed before attempting a reset.