Cold Radiator

Just wondering if anybody can help. I have recenlty moved a radiator in one of the rooms in my house. When I re-filled the rads and started the central heating systems up all the rads worked except one. It was working fine before draining down and doing the work. I have made sure that the rad is bled and there is definitely water in it. If I turn on the central heating and then draw off some water by the drain valve by the rad, hot water is supplied to the radiator and everything heats up as normal. As soon as i shut the drain valve the rad then starts to cool down. Does anyone have any ideas as to what may be causing my problem? Just as a footnote I have a fully pumped vented system.

Cheers

Does the cold rad have a TRV?

Has any work been done on the cold rad?

Does the rad that you moved work afterwards?

Did you vent all rads with the pump off?

On the cold rad, what happens if you shut each valve in turn and open the vent?

Did you open or close any other rad valves anywhere in the system?

Where in the system is the cold rad?

Is the water in the F&E cistern up to the correct level?

Firesharpe said:

Just wondering if anybody can help.

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Have you extended a one pipe system by any chance? If so the 'ring circuit should be continued so that it runs below the new rad position.

Apart from that it will likely be down to a blockage of some sort as Softus is implying

Anybody said:

Apart from that it will likely be down to a blockage of some sort as Softus is implying

Click to expand...

You're nuts. I haven't implied, or eliminated, anything. There isn't enough information yet.

Sorry for the lack of info guys, but I have now sorted the problem by shutting down all the rads except the one that was not warming up. must have been an air lock as it know works fine as do all the other rads. thanks for any replies given.