LG Heat Pump Error Code P0

The P0 code means the system has shut down because the discharge temperature sensor recorded a temperature exceeding 135 degrees Celsius two times within one hour. This is a safety lockout designed to protect the compressor from heat-related damage. The unit will not resume normal operation until the fault is addressed and the system is reset using the K3 reset key.

No. The P0 fault causes the system to shut down automatically, and the unit should not be repeatedly reset and forced to run without diagnosis. Operating a heat pump with persistently high discharge temperatures risks permanent compressor failure, which is a much more costly repair than addressing the original cause of overheating.

The most frequently identified causes are closed or partially closed service valves, low refrigerant charge, and fouled coils that reduce heat transfer. A faulty discharge temperature sensor that reads incorrectly can also trigger the fault. Starting the diagnosis by confirming both service valves are fully open is the recommended first step before investigating refrigerant levels or component condition.

Pressing the K3 reset key can clear the fault and allow the system to attempt restart, but it will not fix the underlying problem. If the root cause is not corrected, the discharge temperature will exceed 135 degrees Celsius again and the P0 code will return within the same or a subsequent operating hour. Always verify that both service valves are fully open before resetting.

Repair costs vary widely depending on the cause. A service call to open a valve or clean coils may run in the range of 75 to 200 dollars. Refrigerant recharge typically costs between 150 and 400 dollars depending on the refrigerant type and quantity needed. Sensor replacement generally falls in the 100 to 300 dollar range, while compressor replacement is significantly more expensive, often ranging from 800 to 2,000 dollars or more including labor.