adjust water pressure on bolier

The tap should be switched off, and not left on! The tap is for adding SOME more water to the system, so once the gauge shows around 1 bar (cold system) then you should turn it off..

You need to make sure the tap is off, and then bleed some water out, either by a drain point in the system (looks like this usually

Full details here:

many thanks. As you've probably gathered central heating systems are like Chinese to me!

I have turned off tap, bled radiators, and pressure has revered back to normal.

Anything else to do before i try to restart system?

fiona

ps one of the links given said not to bleed radiators if you have a combi boiler, is really true? What on earth do you do when they are not functioning correctly an only lower half is hot?

If the pressure is around about 1 to 1.5 bar (15 - 25 PSI) on the gauge when the system is cold then it should be ok. The pressure will rise as it heats up - but should not go over say 2.5 bar.

Nope, sounds like you are ready to go.

Was that a link to one of "our" docs or off site somewhere? Its nonsense obviously.

There is an added complexity to bleeding rads on a combi system (well more exactly a sealed system - and most combis are of this type), in that as you draw air out of the system the pressure falls. Hence you may need to top up as you have done after. If doing lots of rads and working alone this can be a bit tedious since you keep having to go back to the filling loop to top up to maintain the pressure that expels the air.

Sorry, that was in my link, the link I posted was really aimed at people in council accommodation, where they would come out and sort it out, as it would then involve the "complex task" of topping it up afterwards.... ...But as you can see, topping up the system doesn't involve any witchcraft, it is quite easy!

Sorry for the confusion!

Toby...

Ah, ok just read it. I see why they say what they say - although they seem to be assuming that only combis use sealed systems. Perhaps that that is true for their housing stock.