One radiator not working and pipes cold

[oldgirl]

One radiator on 2nd floor is cold n pipes are cold too. There are 4 radiators in this loft area and other 3 are fine.all these radiators are gen off all the time. On rare occasions I've to turn them on when I hv guests. Today I found that the 3 heated up fine, 1 doesn't. Ch system is old but it's working fine. The valve turns ok. Hv bled the radiator. Water that came out was clean. The valve is not a trv.
Usually my husband dealt with all these things but unfortunately he is now quite ill.so I'm learning diy now.
Thanking you all in advance. Any help much appreciated.

 

[ChrisR]

I was going to say it must be a TRV... They have a rubber tapered plug which sticks to the valve seat if they're left shut a long time.

It could be
a TRV but with a normal head so it looks like a normal valve, or
a normal valve whose stem has broken loose inside. Seen a few. If it's on the "return" the water pressure from the pump will hold it shut.

Relatively easy to change as it's at the top of the house.

 

[oldgirl]

Thank u ChrisR. Valve definitely not trv. But are you saying that the valve needs to b replaced? What does it mean ''the return''? Is that the pipe thru which water exits from the radiator? Sorry just trying to understand. Thank you again

 

[Burnerman]

Although water does bleed from the radiator, thats no guarantee that one of the pipes to it (hot water flows in, cool water flows out through the 'return') isn't blocked.....there will still be water there to bleed.
As Chris says, one of the valves may be faulty, and normally what would happen is:
Both valves closed off, and the radiator drained by undoing the valve connections at both ends;
Each valve opened one at a time, to see if water is flowing.
If the water is black (and it will be to some degree) it indicates that there are rust deposits in the system.
This test will indicate whether its a pipe blockage. If a plumber suspects a broken valve, he'll undo the pipe to it and test from there.
John

 

[oldgirl]

Thank you. I'll call a plumber . Will post later to c how this has resolved.
Bfn

 

[oldgirl]

Resolved! !!! Simple. Someone had put the valve cap on the return pipe. So I was not opening the flow pipe. Plumber was v nice and didn't charge me.