Expansion vessel???

[professorplumb]

Combi boiler pressure rising to 2.5-2.7 with flow temp around 73 degrees on potterton Gold combi 33he.

Pressure when called is 1 bar have replaced the filling loop as letting by and also prv as client said was at 4 bar the other day. So is a new expansion vessel needed?? as was working fine before the client experienced any problems beforehand.
Thanks

 

[tamz]

It may just need pumping up.

 

[PaulGas]

As above. Test, if low. Recharge it with PRV open

 

[professorplumb]

Thanks will do

 

[mikegas]

If the pressure is ok check the small pipe to expansion vessel as this can get blocked causing the same fault