Hi everyone,
I've just changed a leaking radiator and had to drain my unvented system to do it. The only other change I made was to reset the expansion vessel pressure to 1 bar (it had no water in it so presumably the diaphragm is intact, but the pressure was almost zero).
When off the system pressure is 1 bar, but when the pump runs the pressure falls by about 0.3 bar depending on demand (how many TRVs are open / DHW etc). It also varies with pump speed.
Is this normal? I doubt the pressure vessel charge was actually zero prior to this because the system behaved normally as it warmed up.
Any help appreciated (as always!).
Cheers,
Dave.
I've just changed a leaking radiator and had to drain my unvented system to do it. The only other change I made was to reset the expansion vessel pressure to 1 bar (it had no water in it so presumably the diaphragm is intact, but the pressure was almost zero).
When off the system pressure is 1 bar, but when the pump runs the pressure falls by about 0.3 bar depending on demand (how many TRVs are open / DHW etc). It also varies with pump speed.
Is this normal? I doubt the pressure vessel charge was actually zero prior to this because the system behaved normally as it warmed up.
Any help appreciated (as always!).
Cheers,
Dave.
