DIY Doctor UK DIY Forums

i have a potterton performa 28(5 years old),at first it had an increase in pressure,to about 3.5 bar,which could be cured(for a while) by using the pressure relief valve. till last week ,when after lowering the pressure,the vale failed,and i couldn't get any pressure atall(after using the filling loop,the pressure would drop to zero).
so, i changed the pressure relief valve,,,now the pressure still increases to about 3.5 bar,even though the boiler is not turned on,and the filling loop is disconnected,,,,,,
can anyone please help???

thanks,,,,brian

Sounds as if it's the expansion vessel, please dont play around with boiler internals as a failed pressure releif valve can have dire consequences. That is why is is only CORGI engineers who by law are alowed to service/install gas appliances. I would get a maintenance contract from the likes of British Gas as with a Potterton Performa you should get used to break downs.

PS when was it last serviced?