A question about the central pin in the thermostatic head of for
instance

https://www.screwfix.com/p/drayton-r...ing-head/3279r

One of my radiators is not coming on. I've taken the head off and if
I rotate the top part (ie hot to cold) the central assembly doesn't
move though I can push it in with a screwdriver and it springs back
but seems to require more pressure than I'd expect the little pin in
the radiator valve could exert.

I've tried a working head from another radiator and the pin retracts
as I go to 5 and protrudes as I go to 0.

So how should it operate and if faulty should the item referred to fix
it?

The pins in both radiators are free and can be pushed down (= off?)



--
AnthonyL

Why do scientists need to BELIEVE in anything?