DEFROST (green) LED flashes - Some protection is active

What does DEFROST LED flashes mean?

The green DEFROST LED on the base board (AA2) is flashing. This indicates that a protection function, other than active defrosting, is currently engaged to safeguard the Heat Pump.

• A protection function is active (e.g., high/low pressure protection, over-temperature).
• Temporary system condition requiring protection.

Click steps to track your progress.

1. 1

   Check the indoor module/control module display for any specific alarm messages or error codes.

2. 2

   Ensure the outdoor unit is clear of obstructions like snow or ice that could trigger protection functions.

3. 3

   Allow the Heat Pump to operate; protection functions often clear automatically once conditions normalize.

4. 4

   If the flashing persists without an obvious cause, or if the Heat Pump is not functioning correctly, contact a NIBE service technician.