We may have found other answers which could help you.
Click here for Combi Boiler Pressure Heatingwater not getting really hot?
Valiant combi compact boiler -low water pressure?
How do I remove Valiant analogue 130 timer from Turbo max combi boiler ?
Constant rise of water pressure in valiant combi echo plus boiler?
Leak on overflow pipe?
Hot water and Central Heating Not coming on?