Single cold radiator

It could be that the lockshield valve has dropped. The valve snaps off and then sits at the bottom of the valve blocking the flow. Of course opening and closing the valve would not show this fault as these limits are set by the threads in the valve.

Adam

Reply to
ARWadsworth
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There could well be an air-lock somewhere. The first thing to try is to turn off all rads except a cold one, and run the system for a bit with the pump at its maximum speed. Any air should collect in the top of the rad, where it can be bled out. Repeat - one rad at a time - with any others which are not getting hot.

When you can get them all hot one at a time, turn them all on again and set the pump back to its normal speed. They should then all get hot at the same time. If some are hotter than others, the system will need balancing.

If there are any radiators which refuse to get hot even when everything is thrown at them, come back, and we'll make some more suggestions.

Reply to
Roger Mills

OK, that sounds like useful practical advice. Will try tonight. Not sure I can set the pump speed any higher (its a WB greenstar, 24 I think) but I get the principle of forcing everything at one rad only and will have a look at the pump settings.

Cheers!

Matt

Reply to
larkim

ok, that sounds like it is doing what it should then...

You say this is a combi. Can you confirm if the system is vented or sealed? (i.e. header tank for vented, or filling loop and pressure gauge for a sealed system). (the former are prone to airlocks, but not usually the latter)

Reply to
John Rumm

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Sealed (no header tank). Before the current boiler (c. 12 months ago) I used to get persistent issues with top rad in the house filling with air, I think from a small perforation in the pipework near the boiler. With current one I don't seem to have this problem, so I don't naturally think there is any air in the system, and I haven't heard any banging etc etc.

I suppose its possible that built up gunk from the old water in the system has been dislodged in the powerflushing and is now blocking the

2 radiators?

Matt

Reply to
larkim

"larkim" wrote

I suppose its possible that built up gunk from the old water in the system has been dislodged in the powerflushing and is now blocking the

2 radiators?

Matt

I had that! After forcing water flow towards the two blocked rads, the blockage moved to one rad only (the two rads were served by the same 15mm flow and return pipes). The crud actually blocked the valve itself, so had to remove the rad, open the valve and poke the blockage through the valve with a tie wrap! Once disturbed, water started to flow out of the vave, so put a hose on the valve to run water into a bowl and complete the de-blocking operation.

Phil

Reply to
TheScullster

Have you tried my method of shutting down all the other radiators and running the heating through just this one?

Dave

Reply to
Dave

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