Swiftflow 80 pressure dropping

Hi,

I have a gloworm swiftflow 80 that was blowing water outside and the pressure was dropping ( when the heating has been on ).
I have had a new pressure release valve fitted and although there is no longer water going outside it is still dropping pressure.
Typical readings are - set pressure at about 1 bar - turn heating on for a few hours - pressure reads about 2.5 bar whilst heating on - pressure reads about 0.4 when heating has gone off.
No signs of leaks anywhere.

Any ideas what could be the problem ?

Many thanks in advance

Mark

Pressure vessel needs recharging for starters

Pressure vessel needs recharging for starters

Hi - is this something I would need an engineer to do - I did have an engineer fit the prv - do you think he would have done this as part of the job ?

Thanks