One radiator not heating up

[Eminybob]

We have one radiator that is not getting hot - or even warm.
It was in the spare room which wasn’t used for years, I had noticed that it had been getting cooler and cooler when on, then eventually stopped heating up, but as we didn’t use the room I wasn’t bothered.
Now we have moved ds in there so need it to work this winter.

Dh has bled it, although there wasn’t really any air trapped so that wasn’t the issue. We have tried turning all the other radiators off to try and force out any air bubbles in the pipe, but that didn’t work.
Anything else to try before getting the professionals in?

We had this with one of ours. The pin inside the thermostat valve was stuck. We took the top of the valve off and gave the pin a gentle tap with a hammer to release it and then it worked fine.

The twisty bit that changes the temperature? Take that off and give it a tap?
Will try that thank you

Thanks for the vid. I’ll get dh to have a look when he gets home.
The other thing I should mention is that the pipes going in and out don’t seem hot either...

Feel along the pipes. If you can find where they change from hot to cold, then there might be a blockage there. Get a hammer and tap them, to hopefully dislodge the blockage.

They go straight into the floor unfortunately.

FIRST OF ALL

Please turn off all the hot ones. Does the cold one now heat up?

This is to diagnose what sort of fault you have, before you start trying to fix it.

Tried that, no it didn’t heat up.

OK, Then try the pin in the TRV next.

Rather than hitting it with a hammer, which might bend or break it, put a soupspoon in the palm of you hand, dome upward, and press on it.

The curve of the spoon prevents the pin from bending sideways, and the spoon prevents the pin from puncturing you.

Always turn TRVs to their hottest setting before you remove or replace the head.

If you have some WD40, put a drop (only) on the pin with the tip of a pencil first, it will perhaps lubricate the sticking part.

TRVs tend to jam if they have been tightened down in summer. There is no need, they will stay freer if not tightened.

Thanks PJ I’ll give it a go.

We’ve got the same issue with just one radiator not working. Plumber said pin stuck in valve, so he’s coming back to replace that and then should be fine

Thank you to all who replied, it was the pin stuck in the valve.
After a lot of pulling, the whole bloody thing came out, spraying dirty water everywhere, but once it was back in the radiator heated up instantly. It’s now hotter than all the others!
Good work, thank you!