LG Heat Pump Error Code CH17

CH17 on an LG heat pump indicates a problem with the water-inlet temperature sensor. This sensor measures the temperature of water entering the unit and provides that data to the main control board. When the board detects a signal outside the acceptable range, it logs CH17 and may restrict or shut down operation to protect the system.

It is not recommended to continue operating the unit while CH17 is active. The heat pump relies on accurate water temperature data to regulate operation and protect components. Running the system without a properly functioning inlet sensor could result in inefficient operation or damage to internal parts.

A power reset may temporarily clear the CH17 code, but the error will return if the underlying sensor or wiring fault has not been resolved. The code is triggered by an active electrical reading outside the expected range, so clearing it without fixing the root cause provides only a brief reprieve. Proper diagnosis and repair of the sensor circuit are necessary for a lasting resolution.

A knowledgeable DIYer can perform the initial diagnostic steps, which involve checking that the sensor connector is firmly seated and measuring resistance at the sensor with a multimeter. The sensor should read approximately 5k ohms at 25 degrees Celsius when unplugged. If wiring and connections look correct but the resistance is wrong, replacing the sensor is a straightforward repair, though accessing internal components may require partial disassembly and some comfort with electrical testing.

Repair costs depend on the root cause. If only the water-inlet sensor needs replacement, parts typically range from around $20 to $80 depending on the specific model, plus labor if a technician performs the work. If the issue is a damaged harness or a faulty PCB, costs can be higher, with PCB replacement potentially ranging from $150 to $400 or more for parts alone.