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I have 1 cold radiator

Community Veteran
Posts: 2,211
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Registered: 18-02-2013

I have 1 cold radiator

Anybody give any advice on a cold radiator please, I've just let a shed load of air out, but the radiator is still cold. Would this likely be a thermostat problem or a blockage ?
20 REPLIES
Community Veteran
Posts: 16,814
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Registered: 06-11-2007

Re: I have 1 cold radiator

Did you bleed the radiators from the highest radiator in the house?
If there is a thermostat on each ( it ) radiator... turn them full on and full off two or three times...
make sure you have the correct pressure showing on your boiler, by adding water from the appropriate feed.
check the pressure after bleeding... and top up as needed...
itsme
Grafter
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Registered: 07-04-2007

Re: I have 1 cold radiator

You are assuming it's a sealed system.
Community Veteran
Posts: 2,211
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Registered: 18-02-2013

Re: I have 1 cold radiator

I have just bled the none functioning radiator so far, it's not a sealed system so no need to re-fill. I do bleed the rads every 6 months or so as a rule. But i've not had a rad go fully cold before.
Community Veteran
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Registered: 10-08-2007

Re: I have 1 cold radiator

I have the same problem!
I had a new boiler installed in September by a highly recommended local (one mile down the road) heating engineer. boiler works OK
Included in the price was flushing and retreating the heating system. After the work was done the bathroom radiator does not work. I have had him back three times to no avail.
I have bled the radiator, there is no air coming out but it does not get warm.
So I have given up, he is not capable of fixing the issue he has caused. I am considering in texting him to ask if he knows of any decent heating engineers who could fix it..
itsme
Grafter
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Registered: 07-04-2007

Re: I have 1 cold radiator

Is the radiator the last one on the feed? Do you flush the system regular and use cleansing and inhibitor fluids?
Community Veteran
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Registered: 12-08-2007

Re: I have 1 cold radiator

Sounds like the radiator needs bleeding Undecided
Community Veteran
Posts: 2,211
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Registered: 18-02-2013

Re: I have 1 cold radiator

No i've never flushed the system, and yes it is the last in the loop downstairs.
itsme
Grafter
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Registered: 07-04-2007

Re: I have 1 cold radiator

Is there a drain point fitted on this radiator?
Community Veteran
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Registered: 10-04-2007

Re: I have 1 cold radiator

If you are sure you got all the air out of the radiator (i.e. water started coming out) it could be an air lock somewhere. You could try closing the valves on some radiators to see if the pump will push it through - don't close all the radiators though!
jelv (a.k.a Spoon Whittler)
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Community Veteran
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Registered: 18-02-2013

Re: I have 1 cold radiator

All sorted... I just followed this little video
-IIsH54 as soon as I unscrewed the valve I heard the water flow into the radiator, no need to use the heavg handed fbh trick! I'll keep an eye on it, if it sticks again i'll just replace the valve.
Superuser
Superuser
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Registered: 22-08-2007

Re: I have 1 cold radiator

That's a good video, as it does mention other possibilities.
My thought went to a bit of sludge in the valve and system balance.
I recall many years ago having helped install a central heating system in a children's home in Romania.  A year or two later I returned after Romanian heating engineers had "messed" with the system resulting in the two remotest rads not heating up at all leaving one room freezing cold and the rest very hot.  Note in winter the temperature over there regularly falls to -30 degC so the room became unusable.
On arrival for that visit my ears were harangued about crap English plumbers (we were all volunteers with just practical skills) had no idea how to install heating systems.  Though tired after a long day travelling, I got out a spanner and went round closing down the check valves on other radiators which their engineers had left fully open.  Left if for half an hour and then invited the complainer to go feel the rads.  Had to smile when without caution he slapped his hand on it and burnt it!
The cause of a cold rad can be the rest of the system's poor balance.
Community Veteran
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Registered: 21-03-2011

Re: I have 1 cold radiator

Is a cold radiator an oxymoron?
Now Zen, but a +Net residue.
Community Veteran
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Registered: 18-02-2013

Re: I have 1 cold radiator

Indeed  Grin
Community Veteran
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Registered: 11-08-2007

Re: I have 1 cold radiator

Not necessarily,  as it would be unlikely that a non-working radiator would be cooler than the room it is in.