LG Air Conditioner Error Code E224

E224 indicates a fault with the water temperature sensor circuit on the main outdoor unit. The control board has detected either a short circuit or an open circuit condition from that sensor. The system uses this sensor to monitor water temperature for safe and efficient operation, so when the reading falls outside acceptable limits, the unit logs E224 and restricts operation to prevent damage.

Operating the system while E224 is active is not recommended. The water temperature sensor provides critical data that the controller uses to protect the compressor and heat exchanger from overheating or freezing conditions. Running the unit without reliable sensor feedback risks equipment damage and could void any applicable warranty coverage.

Repair costs depend on the root cause. A replacement water temperature thermistor is generally an inexpensive part, with the total repair cost including labor typically ranging from around $80 to $200. If the main outdoor control board has failed, parts and labor combined can range from $300 to $600 or more depending on the specific model and regional labor rates.

A knowledgeable DIYer can inspect the sensor connector for corrosion and check wiring continuity using a multimeter. However, confirming whether the thermistor itself has failed requires comparing its measured resistance to the rated temperature-resistance curve, which calls for some technical familiarity. Replacing the sensor or diagnosing a control board fault is generally best handled by a certified HVAC technician.

A power reset may temporarily clear the fault display, but E224 will return if the underlying sensor or wiring problem has not been repaired. Repeatedly resetting the unit without fixing the root cause does not address the fault and may mask a condition that could lead to further equipment damage.