LG Heat Pump Error Code E170

E170 means the LG heat pump detected no change in the evaporator inlet temperature during its piping check routine. This self-test is designed to confirm refrigerant is circulating properly through the system. When the EVAP IN sensor does not register a temperature shift as expected, the unit logs E170 and stops operating. The fault points to a sensor, valve, or address configuration issue in the indoor unit.

The system will typically halt operation when E170 is active, which is intentional to prevent operating without confirmed refrigerant flow. You should not attempt to override or bypass the error and continue running the unit. Doing so could cause compressor damage or other component failures if the underlying refrigerant or valve issue is real. Leave the unit off until the fault is diagnosed and resolved.

Repair costs vary depending on the root cause. If the fix is simply reseating a sensor or correcting an address configuration, you may only pay for a service call, which typically ranges from $75 to $150. Replacing an electronic expansion valve can cost anywhere from $200 to $500 or more depending on parts and labor in your area. A refrigerant recharge, if needed, adds additional cost depending on the refrigerant type and system size.

Some causes of E170 are accessible to a knowledgeable DIYer. Checking and correcting the indoor unit address setting and reseating the EVAP IN sensor on the inlet pipe are tasks that do not require special tools. However, inspecting or replacing the EEV, testing sensor resistance values, and checking refrigerant charge all require technical knowledge and, in the case of refrigerant, EPA certification. If the simple checks do not resolve the error, a qualified technician should complete the diagnosis.

A power reset may temporarily clear the error and allow the unit to restart, but if the underlying cause is not corrected, E170 will return once the system runs its piping check again. Resetting without fixing the root issue, such as a loose sensor or EEV connection, is not a lasting solution. Use a reset only as a step after you have addressed the suspected fault to confirm the repair was successful.