| CODE / | DESCRIPTION | CODE / | DESCRIPTION |
| 0b | Circulation issues | F2 | Temperature limiter has responded |
| 0C | Voltage too low | F3 | Flame signal is already present at burner start |
| 30 | Short circuit temperature sensor | F4 | No flame signal is present |
| 38 | Open circuit temperature sensor | F5 | Air pressure switch fault |
| b1 | Communication fault | F7 | Water pressure sensor fault |
| b5 | Internal fault | F8 | Gas valve closes too late |
| E4 | Supply voltage fault | F9 | Fan speed too low at burner start |
| E5 | Internal fault | FA | Fan idle state not reached |
| E6 | Insufficient water pressure | Fd | Burner control unit fault |
| F0 | Internal fault | FE | Main PCB fault |
| 58 | Dip switches |