have changed 3 way valve problem with no ch, this now works but pressure rising above 3 bar if boiler is used on full temp temp left at half it stays at 2.5 bar?

peter, November 2011

You will find that the expansion vessel has lost it charge. You can repressurise by using a foot pump up to 1 bar of pressure and make sure that the system has no pressure in it otherwise it will give you false readings and its normally sited at the back of the boiler

dmh, November 2011