Thanks Iain
We had the pressure vessel changed last year, (the small ball one with the valve on), should that be charged too and is this anything to do with the problem? It's the one in the middle at the back and is a silvery metal colour.

Angela, May 2008

if you did have the main expansion vessel changed only a year ago, could it just be a blocked pipe to the expansion vessel????

i would press the pin in on the above, if you get a phhsssst then maybe look towards blocked pipe. if you get nothing try a re-charge. if you get water think hmmmm that didnt last long.

iain, May 2008

the small ball one is expansion vessel for the dhw side.

iain, May 2008

if your pressure rises when the heating is turned on, its the expansion vessel at fault. from memory its the big round vessel located behind the boiler. you'd probably have to look over the top of boiler to see it right at the back.

iain, May 2008