5110 <1214> (U4) Heat sink temperature thermistor (TH8) open/short

What does 5110 <1214> (U4) mean?

This fault indicates an issue with the heat sink temperature thermistor (TH8) in the outdoor unit. The thermistor might have a broken connection, a faulty characteristic, or there's a problem with the circuit board.

• Disconnection or contact failure of thermistor connectors.
• Characteristic defect of the thermistor itself.
• Defective outdoor multi controller circuit board.

Click steps to track your progress.

1. 1

   Turn off the power to the outdoor unit at the circuit breaker.

2. 2

   Carefully check the connectors for the TH8 thermistor on the outdoor unit for any disconnections or loose contacts.

3. 3

   Visually inspect the thermistor wires for any signs of damage or pinching.

4. 4

   Restore power and observe if the error clears. If it recurs, contact a service professional.

5. 5

   A technician would typically measure the thermistor's resistance to check its characteristic defect.