We may have found other answers which could help you.
Vaillant F22 fault?
Vaillant igniting issue ( domestic ) not CH?
Vaillant vcw gb242 eh central heating problem?
how do I rectify the fault as detailed below?
What does f.25 mean?
how to fix water pressure its down at bottom of grey part?
Vaillant VCW-Sine18 T3WFH Lights but then goes off after 5 Min?
Vaillant condensing boiler ecoTEC plus?
Vaillant eco plus 531 boiler?
Vaillant 828E - no hot water?
Hot water comes and goes!?
vaillant ecoTEC plus boiler fault code - how to fix?