Britony Combi 80 pressure drop

[Angell]

HELP please!! My Britony Combi 80 has been losing pressure after heating is switched off but climbing high when heating is on and gradually dropping. There is a steady drip from the overflow pipe. It has been topped up twice daily to maintain pressure at 1 -

Plumber has fitted a new external expansion vessel.

The pressure is not climbing high but still drops to half when heating is off.
Pressure is set at one and climbs to 1.5 when in use. Is this normal?

 

[kevplumb]

YES

 

[doitall]

And stop the drip from the pressure relieve valve by renewing it.

 

[corgigazza]

when the plumber(corgi engineer ) fitted new ex vessel did he unblock the small flex pipe that feeds the vessel these always block up use metal coat hanger to unblock.

 

[Angell]

Thanks - I hope that's it for now. xx