Possible Causes

1. Incorrect insertion position of the temperature sensor.

2. The temperature sensor is not properly inserted into the main control board.

3. The temperature connection cable between the outdoor unit and the water tank is not fully inserted, leading to terminal pin displacement/detachment or open circuit of the wiring harness.

4. Unreliable connection or open circuit of the extended extension cable.

5. Damage to the temperature sensor.

6. Damage to the sampling circuit of the main control board.

Solutions

1. Check the correctness of the sensor socket position.

2. Re-plug the temperature sensor.

3. Verify the continuity and reliability of the connection harness and terminals.

4. Inspect and handle the interface of the extended extension cable.

5. Check whether the sensor resistance matches the actual temperature.

6. Replace the main control board.