LG Heat Pump Error Code CH45

CH45 indicates a problem with the condenser pipe temperature sensor on your LG heat pump. This NTC thermistor monitors refrigerant temperature at the condenser coil and feeds that data to the control board. When the sensor signal is missing or out of range, the unit logs CH45 and may limit or stop operation to protect the system.

Continuing to operate the unit with CH45 active is not recommended. The condenser pipe temperature sensor is a key protection input, and without accurate readings, the system cannot properly regulate the refrigeration cycle. Running without this protection risks compressor damage or refrigerant-related faults. Address the fault before resuming normal operation.

A power reset may temporarily clear CH45, but if the underlying fault with the sensor, wiring, or connector is still present, the code will return once the unit restarts and the control board re-evaluates the sensor signal. A reset is useful for confirming whether a fault is intermittent, but it is not a fix. The sensor circuit should be tested and the root cause corrected to prevent the code from recurring.

Some steps are accessible to a knowledgeable DIYer, specifically checking whether the sensor connector is fully seated, undamaged, and free of corrosion. If you have a multimeter, you can also measure sensor resistance with the connector unplugged; the target value is 5k ohms at 25 degrees Celsius. However, if the sensor or wiring needs replacement, or if the control board is suspected, a qualified HVAC technician should complete the repair.

If only the connector needs cleaning or reseating, the repair may cost little more than a service call fee, typically in the range of $75 to $150 depending on your area. Replacing the condenser pipe thermistor sensor generally costs between $100 and $250 including parts and labor. Control board replacement, if required, is a more significant expense and can range from $300 to $600 or more.