Vaillant “How To” Guide.
Below are some step by step guides to assist you with your Vaillant
Boiler.
Fault codes
F.28 Boiler fails to ignite
If the burner fails to ignite after five attempts, the boiler will not operate and switches to “fault”. This is indicated by
the fault code F.28. The boiler will only ignite automatically again once you have reset it manually. To reset the boiler
press the reset button (shown in diagram above) and hold for one second.
If this fault code appears it is advised that you check that your gas meter has credit on it if a credit meter is fitted at
the property. No credit on the meter will not allow the boiler to ignite. The boiler would need to be reset after the
meter has been credited.
F.22 Low water pressure
If the filling pressure for the heating system falls below 0.8 bar, the red bar display and the current filling pressure
flash in the display. If the pressure falls below 0.5 bar the boiler switches off and the fault message F.22 appears in
the display. To restart the boiler you must refill the heating system with water.
