LG Heat Pump Error Code P718

P718 indicates that the outdoor unit discharge temperature has reached a level that triggered third-level protection control. The discharge temperature is the temperature of the refrigerant gas leaving the compressor, and it must stay within safe limits to prevent compressor damage. When this threshold is exceeded, the LG control board activates protection mode to shut down or limit operation. The root cause must be identified and corrected before the system will operate normally again.

No, you should not attempt to force the unit to run while P718 is active. The protection control exists specifically to prevent severe damage to the compressor, which is the most expensive component in the system. Bypassing or repeatedly resetting the error without addressing the root cause can lead to compressor failure and a much costlier repair. Leave the unit off and have it inspected promptly.

Repair costs vary widely depending on the cause. A refrigerant recharge typically runs in the range of $150 to $400 or more depending on refrigerant type and quantity. Replacing a discharge temperature sensor is generally a lower-cost repair, often in the $100 to $250 range including labor. A compressor replacement, if that is the root cause, can range from $800 to $2,500 or higher depending on the unit size and local labor rates. A diagnostic service call is the first step to getting an accurate estimate.

Some basic checks, such as clearing debris from around the outdoor unit, cleaning the condenser coils, and confirming the outdoor fan is running, can be done by a knowledgeable homeowner. However, diagnosing refrigerant charge issues, testing the discharge thermistor, or evaluating the compressor requires specialized tools and, in the case of refrigerant work, EPA certification. It is strongly recommended to have a licensed HVAC technician perform a full diagnosis before attempting any restart.

A power reset may temporarily clear the error and allow the unit to restart, but if the underlying cause, such as low refrigerant, restricted airflow, or a faulty sensor, has not been corrected, the P718 code will return. Repeated resets without fixing the root problem increase the risk of permanent compressor damage. A reset should only be attempted after a proper inspection and any necessary repairs have been completed.