We had a combi and some new radiators installed this year and I plan to replace a couple of the manual bleed valves with automatic valves.
I imagine that I will need to slightly top up the combi afterwards - which should be a straightforward process. The combi, a WB CDi comes with a plastic key which apparently fits in a valve on the underside of the boiler. Is it just a case of turning it on until the pressure gauge is indicating a pressure of around 1 bar and then turning it off?
-- rbel
That sounds about right.
I have done mine a couple of times, and it's a right ball ache to do because my combi boiler is only about 15 inches or less off the floor.
First last - put a space after the two hyphens to make a proper signature separator.
Anyway... How often do you need to bleed the radiators? Mine need doing when I've had it drained down but after a few weeks when it has settled down they don't need doing. Regular bleeding is most likely a symptom of some kind of leak, pumping over (but not if you have a pressurised combi) or internal corrosion generating hydrogen.
Have you put a corrosion inhibitor in it?
Andy
Many thanks. I am lucky in that the base of the boiler is over a metre above floor level.
Thank you for the reminder
Infrequently. Given that the pressure gauge is not indicating a problem I think a leak is unlikely. I just like the idea of not having to think about it.
Yes
I would worry about a leak developing at some time in the future. Or failing to work. There should be no need for such things.
If there is air/gases in your system, one of these would disguise the fact you have a problem that needs attention.
The key enables the filling loop. There is a plastic tap thing alongside it which actually lets the water in.
Why? You shouldn't need to bleed a system that has inhibitor at all once it has settled down after a few weeks. Automatic valves will just hide a problem unless you keep a beady eye on te pressure guage. If you don't you may go away for a day or three, an automatic valve lets a bit of gas out, the pressure drops and the boiler locks out. Not good in the middle of winter.
Just feel te tops of the rads occasionally, a cold top has gas in it. You can then attend to the problem when ready and not have to do it two hours before you are about to go away as the boiler has locked out...
On 29 Nov 2012, you wrote in uk.d-i-y:
I think they are pointless and usually leak a little. It only takes minutes to try each radiator - but as others have said, it is often just one or two that get air in and only for a short time.
Interesting, what make have you tried?
-- rbel
rbel wrote in news: snipped-for-privacy@4ax.com:
Some were already installed. I removed them as they were often damp. They seemed to rely on a washer swelling when it got wet. I prefer the simple mechanical action of a normal valve.
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