We may have found other answers which could help you.
Click here for Gas Boiler StartVaillant F22 fault?
Vaillant vcw gb242 eh central heating problem?
how to fix water pressure its down at bottom of grey part?
What does f.25 mean?
Vaillant condensing boiler ecoTEC plus?
Vaillant VCW-Sine18 T3WFH Lights but then goes off after 5 Min?