U4 - Overheat protection activated

What does U4-1 mean?

The system has initiated an overheat protection shutdown. This occurs when internal temperatures exceed safe operating limits, often due to restricted airflow or system strain.

• Blocked condenser or evaporator coils.
• Insufficient airflow to indoor or outdoor units.
• Overworking compressor.

Click steps to track your progress.

1. 1

   Turn off the unit and allow it to cool down for at least one hour.

2. 2

   Check for and clear any visible debris from the outdoor unit coils and ensure indoor filters are clean.

3. 3

   Verify that nothing is obstructing the airflow around either the indoor or outdoor unit.

4. 4

   If the error reoccurs, contact a service professional for further diagnosis.