Outdoor heat exchanger sensor abnormal — RUN LED flashes 3 times, TIMER LED flashes 7 times

What does 37 mean?

The outdoor heat exchanger sensor is reporting abnormal readings, such as –55°C or lower (or higher) repeatedly, which affects the unit's ability to operate correctly.

• Outdoor heat exchanger sensor is short-circuited or otherwise faulty
• Faulty outdoor PCB

Click steps to track your progress.

1. 1

   Turn off the main power to the unit.

2. 2

   Inspect the outdoor heat exchanger sensor for any visible physical damage.

3. 3

   The sensor's resistance would need to be checked by a technician to confirm a short circuit or fault.

4. 4

   If the sensor appears physically normal, the outdoor PCB may be faulty and require professional diagnosis.