We may have found other answers which could help you.
Click here for Fault Fill PressureHot water and Central Heating Not coming on?
Valiant F22 low pressure problem?
Valiant combi boiler 2005 installation?
Valiant combi compact boiler -low water pressure?
Leak on overflow pipe?
How do I remove Valiant analogue 130 timer from Turbo max combi boiler ?