Samsung Heat Pump Error Code E118

E118 indicates an equal oil valve 1 self-diagnosis error. The heat pump control system detected that oil valve 1 either failed to open or close properly during its diagnostic cycle, or the temperature sensor associated with that valve is disconnected or defective. This valve is part of the oil equalization system that keeps the compressor lubricated.

Continuing to operate the heat pump with an active E118 error is not advisable. The oil equalization system protects the compressor from oil starvation, and running the unit with a faulty oil valve can lead to compressor damage over time. Shut the unit down and have it inspected promptly.

Repair costs depend on the specific component at fault. If only the sensor needs to be reseated or a wiring connection repaired, costs may be limited to the service call fee, typically in the range of $75 to $150. Replacing a defective temperature sensor or oil valve can add $100 to $400 or more in parts and labor, depending on the specific unit model and local labor rates.

The first diagnostic step, checking whether the oil valve 1 temperature sensor has come loose, can be performed by a knowledgeable DIYer if they are comfortable accessing the outdoor unit. However, testing valve coil continuity, measuring sensor resistance, or replacing refrigerant-side components requires a certified HVAC technician. Attempting repairs beyond the sensor connection check without proper training is not recommended.

A power reset may temporarily clear the error code, but if the underlying fault is still present, the E118 will return once the control board runs its self-diagnostic routine again. A reset alone does not fix a failed sensor, disconnected wiring, or a faulty valve. The root cause must be diagnosed and corrected for the error to stay cleared.