Alarm 228 — Failed defrost

What does Alarm 228 mean?

The system's defrost cycle has failed. This typically indicates that ice buildup on the outdoor unit's evaporator has not been cleared successfully, or there's an issue preventing the defrost process from completing.

• Frozen evaporators in the F2120 outdoor unit due to severe ice buildup.
• Compressor stopping unexpectedly during defrost operation (older firmware issue).
• Insufficient airflow around the outdoor unit due to obstructions.
• Malfunction in the defrost heating elements or reversing valve.

Click steps to track your progress.

1. 1

   Clear any snow, ice, or debris from around the F2120 outdoor unit to ensure adequate airflow.

2. 2

   Manually initiate a defrost cycle from the control panel menu (e.g., Menu 5.11.1.1 if available).

3. 3

   Update the NIBE SMO 20 firmware to version 7840R3 or later to prevent compressor stops during defrost.

4. 4

   If the alarm persists, contact service personnel to inspect the evaporator and compressor.