Outdoor Unit LED 4 Flashes — Heat-exchange thermistor (outlet) error

What does 4 Flashes (Outdoor Unit) mean?

The LED on the outdoor unit flashes four times. This indicates an error with the heat-exchange thermistor located at the outlet of the heat exchanger.

• Faulty heat-exchange thermistor.
• Loose or damaged wiring connected to the thermistor.
• Improper heat exchange due to low refrigerant or airflow issues.

Click steps to track your progress.

1. 1

   Restart the heat pump system by turning off the main power for at least one minute, then switching it back on.

2. 2

   Check that the outdoor unit is free from obstructions and has good airflow.

3. 3

   Ensure that the indoor unit's filters are clean and not restricting airflow.

4. 4

   If the error continues, contact a qualified technician to diagnose the specific thermistor and system components.