after overpressurising the system we operated the pressure relief valve and the pressure then reduced to required level of 1.5 but its not staying there - after turning back the pressure relief button fully we find the water continues leaking from the expansion pipe outside and only stops when empty and pressure below minimum level.

Bettee, September 2009

You have committed the cardinal sin - never reduce pressure via the prv as it won't seal afterwards. Much better to have a new one fitted now.

John, September 2009