Thermostatic rad valve

[Ra!]

Hi

A valve jammed on position 1 so I've taken it off. The pin seems fine, goes up and down, so I went and bought a new thermo head (not replacing the actual valve).

I can't screw the new thermo on! The thread looks fine. Am I missing a trick here? The old and new fixings look identical. I've tried clock and anti-clock.

Thanks in advance!

 

[MANDATE]

With valve open pin will protrude 3 or 4mm, so the head will have to push this down. Best for head to be fully anti clockwise position.
Some heads have adjustable locking devices that prevent head being fully open so ensure this is not interfering with assembly.

 

[D_Hailsham]

The old and new fixings look identical. I've tried clock and anti-clock

Presumably the same make!

If the removed head is an old version there may be differences; e.g Drayton TRV3 heads are slightly different from TRV4, so they made a converter.

You need to have the head set to Max when you screw it on
Should be clockwise, looking from above.