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Central heating works except for one radiator

Postby ches501 » Sun Nov 01, 2009 6:20 pm


As stated in the heading, my central heating system works with the exception of one bedroom radiator. The pipe leading into the radiator feels hot, but the radiator is cold. I have tried bleeding it but there is no air trapped. I have turned the valve on the in pipe but again no change

Any thoughts appreciated
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Simply Build It

Postby DEEARR2 » Sun Nov 01, 2009 9:29 pm

Have you tried turning off all other radiators via their local valves leaving this one open. If this shows an improvement then your system needs balanced in favour of this radiator.
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Postby rosebery » Sun Nov 01, 2009 10:31 pm

If its a TRV on the flow remove the head completely so that the valve springs fully open. With the head off press down on the centre of the valve to make sure it is operating. They do get stuck. If its stuck shut then it will not allow any hot water into the rad - hence cold rad. Wiggle it up and down against the spring to free it up. If its totally seized then you are probably looking at replacing it.

Also have you checked that the lock shield valve (ie the return) is open?

If the TRV is operating properly and the LS valve is open then its possible that the rad may be well sludged up. In which case isolate it, take it off the wall out into the garden and flush it through with mains pressure water. Then rehang and try again.

However there is also another possibility. With the heating running and hot let more than just a dribble out of the bleed valve so that you persuade the rad to fill with hot water and see if that gets a flow going. It will probably take the best part of a bucket load so make sure that your F&E tank is functioning properly if you have one or that there is someone on hand to top up the pressure at your combi if thats what you have.


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