In our house we have one radiator that is not getting warm – all the others are fine.

The valves on both sides of the radiator are 'open', and I have bled the radiator and water comes out instantly.

From my research on the net, the next thing i'm going to try is taking the top off the thermostatic valve – it seems that the pin can become stuck.

The advice i've seen is to hit it with a hammer 😯

Now i know this can solve all manner of problems, but is it a gentle tap or or a full blown bang?

Will there be any visible sign that the pin is un'stuck'?

If you take the top off the TRV you should be able to see if the pin in the centre is up or stuck down by comparing to another valve.

ok, – i'll try that later.
thanks

Don't hit it, that's not necessary.

Just squeeze it up and down a few times with the blade of a screwdriver or something.

A bit of WD40 won't hurt either.

Mine usually need unsticking after a summer of no use (and my rad valves too!), I tend to squirt the pin in the thermo valve with a bit of bike lube and manouver it up and down with some pliers.

@donald – thanks – I'll do that instead of the hammer – it might have to be GT85 – I haven't got any WD40…. at least it will smell nice.

STW to the rescue once again!

Also have been told to leave these valves open in the summer. Bit late now though.

Some TRV's are very poor quality. I made the mistake of fitting out my house 4 years ago with relatively cheap Italian made ones from Screwfix. The whole lot failed within 2 years, they stick open, they stick closed, just don't work at all now, and no amount of "freeing them up" by pressing the pin with fix them.

Morale: Use only well known big brand (ie not cheapo) TRV's next time!

RESULT!

The pin has been 'un-stuck' and daughter No.1 now has a warm radiator!

cheers folks.