U2 - 3 red flashes, 1 green flash — High discharge temperature

What does U2 mean?

This fault indicates excessively high discharge temperature, often due to insufficient refrigerant, a faulty thermistor, or high ambient operating conditions.

• Lack of refrigerant
• Faulty discharge thermistor
• High ambient temperatures
• Compressor inner thermostat (49C) tripping

Click steps to track your progress.

1. 1

   Check refrigerant levels (requires professional).

2. 2

   Verify the discharge thermistor is functioning correctly.

3. 3

   Ensure operating temperatures are within the unit's specifications.

4. 4

   Check if the 49C thermostat has tripped.