We may have found other answers which could help you.
Click here for Water Changed DiaphragmVaillant eco plus 531 boiler?
Vaillant VCW-Sine18 T3WFH Lights but then goes off after 5 Min?
Advice?
how do I rectify the fault as detailed below?
Vailliant turbo max plus 824e?
Vaillant 828E - no hot water?