Viessmann Vitodens 050-W fault FD
Burner blocked, burner control unit fault
Gas boilerWhat it means
Burner is blocked due to a fault in the burner control unit.
Likely causes
- Burner control unit fault
- Flue system leak causing flue gas recirculation
- Incorrect gas flow pressure
Where to start
- Check ignition electrodes and connecting cables.
- Check whether a strong interference (EMC) field exists near the appliance.
- Press 'Reset' (see page 58).
The full answer, free
- 32 more checks in order
- The readings and component tests from the manual
- How to put it right, step by step
- The manual page for this fault (page 58), right under the answer
Safety: Isolate gas and power before you open the case. If you have been into the gas side, do a tightness test, and a combustion and flue check before you hand back. Gas Safe (UK) or RGI (Ireland) work only.
From the Viessmann manual for the Vitodens 050-W. Check the model on the data plate before you order parts.