Cold pipe from rad

[RrogerD]

I have a radiator in the conservatory. It's all on 10mm micro-bore.
It's hot to the touch on the inlet pipe but the rad itself is cold and the outlet pipe also cold.
Could this simply be an issue with the TRV (it's on the return end) or is it more sinister and the whole rad and / or return pipework is blocked? Is there an easy way to determine the issue without taking the rad off? I'm pretty nervous around anything water and particularity, central heating. It could 'orribly wrong.

 

[terryplumb]

Undo and remove the actuator head off the TRV body, there is a pin in the middle of the body. Press it downwards against it's spring pressure,it should move freely down and spring back up when released ( only a few millimetres). If it doesn't it could be stuck closed internally.

 

[Harry Bloomfield]

Undo and remove the actuator head off the TRV body, there is a pin in the middle of the body. Press it downwards against it's spring pressure,it should move freely down and spring back up when released ( only a few millimetres). If it doesn't it could be stuck closed internally.

If that doesn't help, try - turning all the radiators off, except that one, and try running the system. Report back, whether, or not, you resolve it.

Note the valve settings, before you start, so you can easily reset them.

 

[dilalio]

You can usually use the upturned head of the removed trv to push the pin down.
If this fails, gentle taps with a hammer to get it moving or very gentle push and pull with pliers.
It's very common for them to get stuck once a year.