Samsung Air Conditioner Error Code P518

P518 indicates that the outdoor unit's discharge temperature has exceeded a safe threshold, triggering the system's third discharge temperature protection control. The unit shuts down or reduces operation to prevent compressor damage. This is a protective fault, not a failure of the unit itself, but it signals that something in the refrigerant or cooling circuit needs attention.

No, you should not continue operating the unit when P518 is active. The code indicates the compressor is at risk of overheating, and running it in this condition can cause permanent compressor damage, which is a very costly repair. Turn the system off and contact a technician to diagnose the root cause before resuming use.

Repair costs vary widely depending on the cause. Cleaning the condenser coil or replacing a discharge temperature sensor typically runs in the range of $75 to $250 including labor. Refrigerant recharge and leak repair can cost $150 to $500 or more depending on the type of refrigerant and the extent of the leak. If the compressor itself is failing, replacement costs can range from $800 to $2,500 or higher depending on the system size and model.

Some basic checks are within reach for a knowledgeable homeowner, such as cleaning debris from the outdoor condenser coil, checking that the outdoor fan is spinning, and ensuring nothing is blocking airflow around the unit. However, diagnosing refrigerant charge levels, testing sensor resistance, and inspecting the compressor require professional tools and EPA 608 certification. For most cases of P518, a licensed HVAC technician should perform the repair.

A power reset may temporarily clear the code and allow the unit to restart, but if the underlying cause is not resolved, the error will return, often quickly. Repeated cycling without fixing the root cause increases the risk of compressor damage. A reset should only be used as a temporary step while arranging for a proper diagnosis, not as a permanent solution.