Cold radiator & no bleeding point?

[NeedajobBob]

Our heating is on now and I've just realised the reason the hallway's so cold is because the radiator isn't warm at all, it's ice cold. It's got a 'Honeywell' thermostatic knob on one end and this is turned up. I felt both the pipes rising from the floor and they're stone cold too. I might have expected one of them to be warm at least There is a false 'console table' fixed over the rad to hide it slightly and I put my hand underneath to see if I could find the bleeding point, because maybe it needed bleeding? But there is no bleed point. How weird. Neither end has anywhere to fit a rad key? (it's a 'Barlow' style rad) That aside, does anyone have any idea why this rad alone is stone cold? All the others are ok. Also, it is not the last one in the chain. Do you think someone has fiddled with the nuts on the pipes at some time, would that make a difference? I just can't figure out what's going on. There's no one here to meddle with a rad! It worked ok last year.

The TRV might have seized, especially of it has been screwed to "0" all summer. Please post a photo of the knob and the nut or knurled ring underneath it. Also the knob or spindle at the other end.

This is much more likely than a bleeding problem.

When did it last work?

I found this video which shows the construction quite well

and is similar to some Honeywell valves

A few tips:

If taking the head off, screw it to the highest setting first, to remove pressure from the plunger on the pin

Press your hand on the top of the head to hold it still while you undo the knurled ring

Don't pull on the pin, it might pull out

Don't hit the pin, you may bend or break it

Give the pin a clean and lube with a toothbrush and a bit of WD40 (spray it into a jar and dip your toothbrush into it). A third of a drop is enough.

To press on the pin, only push it directly downwards so as not to bend it. Don't push it with your thumb or hand, the pin may puncture your skin. Put a soupspoon in the palm of your hand, dome upwards, so the pin will naturally try to find the centre. Try pushing and releasing the pin to try to loosen it and it may pop up.

If it does, brush and wipe clean, put the head back (window facing out) and press it down while you tighten the ring.

Piglet, fabulous thanks. I'll post an update with pics later.

I'm just off to watch the video now.

The valve was left on the highest setting '6' since last winter. It worked well then with no issues.

I bet it's a simple fix ultimately, but I'm a bit afraid to try taking it apart in case I spray water everywhere

you can take the thermostatic top off, water will not come out.