LED OFF
No board power or board failure
This code typically points to
- No 24V control power
- Blown fuse
- Transformer issue
- Failed control board
Next checks to confirm
- Verify 24V at board
- Check low-voltage fuse
- Check transformer secondary
- Verify wiring integrity
Escalation
If power is confirmed at board and LED remains off, board failure is likely.
Reset behavior
No reset until power restored.
Service Soon
Schedule repair