While you wait for answers, we may have found some information which could help you.
Click here for Vaillant F22 Water HotVaillant eco plus 531 boiler?
Vaillant 828E - no hot water?
Vaillant VCW-Sine18 T3WFH Lights but then goes off after 5 Min?
vaillant ecoTEC plus boiler fault code - how to fix?
Vaillant ecotec 831 plus?
Vaillant condensing boiler ecoTEC plus?