| Fault Code |
Cause of Problem |
| F.00 |
Flow temperature sensor |
| F.00 |
Flow temperature sensor |
| F.10 |
Flow temperature sensor short circuit |
| F.11 |
Flow temperature sensor short circuit |
| F.12 and F.91 |
Cylinder temperature sensor short circuit |
| F.13 |
Domestic hot water cylinder temperature sensor short circuit |
| F.20 |
Safety switch-off – overheating temperature reached |
| F.22 |
Safety switch-off – low water pressure in the boiler |
| F.23 |
Safety switch-off – temperature difference too great (NTC1/NTC2) |
| F.24 |
Safety switch-off – temperature rise too fast |
| F.25 |
Safety switch-off – flue gas temperature too high |
| F.27 |
Safety switch-off – fault in flame detection |
| F.28 |
Ignition unsuccessful when starting up |
| F.29 |
Flame loss |
| F.32 |
Fan frost protection function active – fan speed outside the tolerance values |
| F.33 |
Fan frost protection function active – air pressure switch fault |
| FA9 |
eBUS fault – voltage too low |
| F.61 |
Gas valve control system fault |
| F.82 |
Gas valve switch-off control fault |
| F.83 |
EEPROM fault – electronics defective |
| F.64 |
Electronics/sensor/analogue-to-digital converter fault |
| F.85 |
Electronics temperature too high |
| F.67 |
Value sent back by ASIC is incorrect (flame slgnal) |
| F.88 |
Unstable flame (analogue input), underfloor heating contact or gas valve fault |
| F.70 |
Invalid product code (DSN) |
| F.71 |
Flow/return temperature sensor |
| F.72 |
Deviation in the water pressure sensor/return temperature sensor |
| F.73 |
Water pressure sensor not connected or has short-circuited |
| F.74 |
Electrical problem in the water pressure sensor |
| F.75 |
Pressure sensor fault |
| F.78 |
The safety cut-out in the primary heat exchanger is defective |
| F.77 |
Fault: Condensate or smoke |
| F.78 |
Interruption to domestic hot water (DHW) outlet sensor at external controller |
| F.83 |
Burner temperature sensor fault |
| F.84 |
Flow/return temperature sensor fault |
| F.85 |
Temperature sensor fault |
| F.87 |
Electrodes fault |
| F.89 |
Pump fault |
| Connection |
No communication between the printed circuit board (PCB) and the user interface |
