We may have found other answers which could help you.
Click here for Gas Heater WaterWhat does f.25 mean?
vaillant ecoTEC plus boiler fault code - how to fix?
Vaillant VCW-Sine18 T3WFH Lights but then goes off after 5 Min?
Vaillant eco plus 531 boiler?
Vaillant F22 fault?
how to fix water pressure its down at bottom of grey part?