We may have found other answers which could help you.
Click here for Water Problem Perfectlyhow do I rectify the fault as detailed below?
Advice?
how to fix water pressure its down at bottom of grey part?
Vaillant VCW-Sine18 T3WFH Lights but then goes off after 5 Min?
Vaillant F22 fault?
Problem with the pressure in combi boiler?