leaking radiator valve on a sealed system

michaelob · 27 Dec 2006

Hi,

I have a leaking radiator valve and I was about to try and change it. It was recommended I drain the heating system but I have now established that the heating system is a sealed heating system. Should I get a qualified plumber to change the valve for me? Or how do I change a radiator valve on a sealed system?

Thanks
Michael

Steady · 27 Dec 2006

Fact that it's a sealed system makes the job no more difficult -
in fact refilling after draining down is quicker.

Maybe you envisaged doing it without draining down. Unfortunately this isn't really an option with a sealed system. You must drain down (or freeze pipes). If your plumbing skills are not the best I would advise draining down in all cases as you are more likely than not to get a leak after doing the repair/ valve swap.

michaelob · 27 Dec 2006

Hi,

Thanks for the reply to my post. I have seen lots of info about draining a non sealed system. How do you drain a sealed system?

Cheers
Michael

kevplumb · 27 Dec 2006

same way just close the rest of the rad valves and keep most of the water in the rads

JohnD · 27 Dec 2006

If you close the valve at the other end of your radiator, not much water should come out (beacsue it is sealed, water will not run out fast if air can't get in to replace it)

I must admit though I have never had a sealed system, but an open syst that's bunged is like that. You mustn't have more than one "open" end at a time. And of course the filling loop must be off.

michaelob · 27 Dec 2006

Hi,

So if I just close off the water feed to the boiler ( by turning off the mains water supply) Shut off all the values on the radiators (to keep the water in the radiators). Drain the water from the radiator with the leak and at the same time emptying the water from the system, change the value and then turn on the main water supply and then the turn on the radiators.

Are there any important bits I;ve missed out?

Cheers
Michael

kevplumb · 27 Dec 2006

if I just close off the water feed to the boiler ( by turning off the mains water supply)

no need to but switch the boiler off

you will need to repressurise the system (see FAQ at the top) and bleed the air out of the rad

michaelob · 27 Dec 2006

Hi,

I've just been speaking with someone and I was telling them I could find the drain off value on my heating system. He said that I should have one , is this correct?

Cheers
Michael

kevplumb · 27 Dec 2006

yes you should have one (somewhere)

JohnD · 27 Dec 2006

If not, then fit a lockshield with drainoff on at least one of your downstairs rads.

michaelob · 27 Dec 2006

Thanks for all your replies, much appriciated. I looked around yesterday and couldn't find any of drain point anywhere. So I think it's time to call a plumber and I should stick with fixing computers.

Cheers
Michael

JohnD · 27 Dec 2006

Bah, a few big spanners will widen your horizons and enrich your lifetime experience.

michaelob · 27 Dec 2006

The big spanners and life experiences are good but it's the big pools of water that I worry about and the missus moaning for weeks that I've broke the central heating.

Cheers
Michael

sime10 · 28 Dec 2006

Michaelob is the V not working on your keyboard? Its a Valve not a value

namsag · 28 Dec 2006

Sealed system there is no need to drain it.. find the auto air vent or vents and screw the cap down.Or if combi with decent isolating valves turn these off. Then release pressure through a rad bleed nipple or crack the connection on the valve you are changing water will soon stop as a vacum is created you can then change valve with very very little or no water at all coming out. Turn valve on other side of rad off just to be on safe side. Then repressure when complete

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leaking radiator valve on a sealed system

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