I'm about to drain our cental heating system so that i can fit new radiator valves and thermostats. Once i've done this, i'll obviously need to repressurise the boiler - a Potterton profile prima. But the boiler appears to have no pressure guage - so how can i set the pressure? Any advice?

marc, July 2007

ah-ha! of course... many thanks again for your help. much appreciated

marc, July 2007

are you talking about the copper hot water cylinder that stands in the cupboard ?
if so that the hot water for your tap's.

you will need to go in the loft and find the small plastic tank, and either turn off the water supply or tie up the ballcock.
or when you drain rads they will just keep filling.
when your ready to get system up and running again just turn on or release ballcock and the system will fill, bleed all rads and you should be ok.
sometimes depending on how system is piped the boiler,pump can get airlocked, but nothing to worry about.

hi-spec plumbing, July 2007

there's a large hot water tank immediately below the boiler. no pressure guage on that either. do you mean that i don't NEED to repressurise? it'll do it on its own? many thanks for your help!

marc, July 2007

>But the boiler appears to have no pressure guage


that's because it's a open vented system not sealed check in the loft if you have two plastic tanks one small one large, the small one is your heating tank.

hi-spec plumbing, July 2007