potterton 80e pressure issues

[felts28]

the boiler is set at 1.5 bar and when the heating is turned on, for the first hour or so the boiler goes to above 3 bar and drips out the pipe outside(between say 50ml - 100ml).it then settles down to normal.
in the morning the pressure is down to 1 bar (the heating has been off).
when i then use hot water, without the heating being on,the pressure goes back up to 1.3 bar.this has happened for a few days now.i thought it was the expansion vessel, now i'm not so sure.

 

[ianmcd]

Yes it is an expansion problem either vessel has discharged or communication hose is blocked

 

[felts28]

i've had the expansion vessel pumped before and i don't remember the pressure gauge going up when using the hot water while not having the heating on.
i still haven't had to top the boiler up.

 

[felts28]

i have now drained the system.
i've read the link on how to represurrise the vessel.
do i now pump up to 1bar then fill the boiler water up to 1bar