We may have found other answers which could help you.
Click here for Saying Code Comhow to fix water pressure its down at bottom of grey part?
Vaillant 828E - no hot water?
Vaillant eco plus 531 boiler?
Vaillant condensing boiler ecoTEC plus?
Vaillant vcw gb242 eh central heating problem?
Vaillant F22 fault?