Hi all. Had a new heating system with Potterton Performa 24 boiler fitted as part of refurb. Everything worked fine until the builders came back to paint behind the radiators. They removed the rads to paint then refitted. Ever since then only one rad in the house gets hot, the others all cold. Fell out with builders so they are refusing to come back and sort it. Tried bleeding rads but no luck as pressure seems low on boiler meter. I know this is going to be a simple answer as everything was fine before so forgive my ignorance but could someone tell me what the pressure is supposed to be, the process for filling the system (they did tell me but I forgot), and is there an order that is best to bleed the rads to get water all round the system again. Thanks in advance!

Darren, November 2008

Hi Darren
There is no seqence on bleeding rads, as yours is unvented. The system pressure should be between 1 and 1.5 bar. If rads not working check rad valves are open. If problem still occurs shut all rads down (turn off) in order to force water through the rad.

mike alex, November 2008

turn boiler to 0.

using filling loop under boiler raise pressure to 2 bar.

make sure all valves are open on radiators, trv and lock shield end.

starting downstairs bleed one rad at a time until full then return to boiler to check pressure.

continue to bleed downstairs and return to boiler between bleeds. when pressure drops, top up again before bleeding next rad.

when downstairs is done stroll round upstairs doing the same, bleed check pressure top up if necessary.

when you have a couple left to do allow pressure to drop a bit more as when you've fully bled the system you'll want to end up with boiler on 1.5 bar.

turn boiler ch dial to low and turn to ch+hw on selector switch. allow boiler to run until you hear ignition then turn back to 0 on selector switch for a couple of minutes. (should get a bit hissing from boiler air vent)

turn back to ch and keep it on low and see how she runs.

after running on low for a bit allow to cool and re-check pressure as you'll probably have dropped a bit from the auto air vent. When cool, re-set to 1.5

turn boiler ch dial back to required setting after boilers been running for a bit.

thats about as failsafe an explanation as i can give.

iain, November 2008