While you wait for answers, we may have found some information which could help you.
Click here for Clock Boiler TurnVaillant VCW-Sine18 T3WFH Lights but then goes off after 5 Min?
Problem with the pressure in combi boiler?
Vailliant turbo max plus 824e?
Vaillant F22 fault?
how to fix water pressure its down at bottom of grey part?
Vaillant 828E - no hot water?