boiler loses pressure down in red when I pressure it back to 1.5 it expands to the red 3 bar and releases water. when bolier switched off gauge says 0bar but it still lights upand works fine I have changed gauge as i thouht it was faulty but still the same. Bled the rads they are air free.Boiler runs ok but creeps up to 3bar and leaks out the prv but works fine. Then the next time the boiler comes on it is back down to 0 bar. has anyone got a answer Thanks AA

Andy A, March 2011

May be pressure vessel lost air pressure, system pressure to z bar and fill air in vessel with foot pump to 0.9 bar, than fill pressure to 1.5 bar and boiler on and if pressure still rise to 3 bar and vessel is faulty. you no need to replace it but simply fix another new one on heating circuit and that should run fine.

k, March 2011