LG Heat Pump Error Code P704

P704 indicates an outdoor unit overload 1 protection control error. The heat pump's protection system has detected an abnormal overload condition in the outdoor unit, typically related to the compressor circuit. The unit shuts down or limits operation to prevent damage to the compressor and associated components.

No, you should not attempt to force the unit to operate while P704 is active. The error code exists specifically to protect the compressor from damage caused by overloading. Continuing to operate the system could cause permanent compressor failure, which is a significantly more expensive repair than addressing the original fault.

Repair costs vary widely depending on the root cause. A wiring repair or overload protector replacement may cost anywhere from $100 to $350 in parts and labor. Compressor replacement, which represents the worst-case scenario, can range from $800 to $2,500 or more depending on the unit and local labor rates. A diagnostic visit is the first step to getting an accurate estimate.

Some basic checks, such as inspecting the outdoor unit for airflow obstructions or verifying the unit has cooled down after a thermal event, can be done without special tools. However, diagnosing the overload protector, checking refrigerant pressures, and testing compressor electrical components require professional tools and qualifications. It is strongly recommended to have a certified technician perform the repair.

A power reset may temporarily clear the code, particularly if the overload protector tripped due to a thermal event and the unit has since cooled down. However, if the underlying cause is a mechanical failure, a refrigerant issue, or a wiring fault, the code will return. A reset without diagnosis is not a solution and the problem must be identified to prevent further damage.