LG Heat Pump Error Code CH15

CH15 indicates that the leaving water temperature, the temperature of water exiting the heat pump, has exceeded 72°C. This is a protective fault that shuts the unit down to prevent damage to the heat exchanger, compressor, and pipework. The most common reasons are reduced water flow through the heating loop or the heating demand being satisfied while the unit continued to operate. The system should be inspected before it is restarted.

Yes, a leaving water temperature above 72°C represents a genuine overheat condition that can stress pipework, fittings, and connected components. The heat pump shuts down automatically as a protective measure, which is the correct response. You should not attempt to bypass this protection or repeatedly restart the unit until the underlying cause has been identified and corrected.

Repair costs vary widely depending on the cause. A simple fix such as bleeding an air lock or adjusting a setpoint may cost little beyond a service call fee, typically in the range of $80 to $150. Replacing a faulty water temperature sensor or circulation pump can range from $150 to $500 or more including parts and labor. Refrigerant-related repairs tend to be more involved and can exceed $500 depending on what is needed. A technician will need to diagnose the specific cause before an accurate estimate can be provided.

Some causes of CH15 can be addressed without specialized tools, such as checking whether the room thermostat is satisfied, verifying the circulation pump is running, and confirming system pressure is within normal range. However, if the cause is not immediately obvious, such as a sensor fault, refrigerant issue, or internal component failure, a qualified technician should inspect the system. Restarting without identifying the cause risks repeat faults or component damage.

A reset may clear the fault code temporarily, but if the root cause is still present, the unit will overheat again and CH15 will return. Before resetting, allow the system to cool, check water flow, verify thermostat and zone valve status, and confirm system pressure is normal. If you cannot identify a clear cause, do not continue resetting the unit without professional inspection.