We may have found other answers which could help you.
Click here for Top Up Central Heating Pressure Combivaillant ecoTEC plus boiler fault code - how to fix?
Vaillant F22 fault?
how to fix water pressure its down at bottom of grey part?
Vaillant eco plus 531 boiler?
how do I rectify the fault as detailed below?
Vaillant ecotec 831 plus?