Thermostatic Radiator Valve Not Working?

[Foresty Forest]

We couldn't turn the radiator off in the bedroom, so I bought a new valve (Pegler Bulldog Gen2). I fitted the sensor with 5 in the window and turned it to 0, but this doesn't work either. Am I missing something or do I need to replace the valve body as well? Btw We're in a hard water area.

 

[CBW]

Sounds like a classic case of the trv pin being stuck. Replace the whole valve after checking this out.

 

[Madrab]

As suggested, check that the valve pin moves, if it does then unless the TRV head is the same as the one that came off of it then it may not work. Not all TRV heads are the same, the internal rod may not move far enough to depress the pin fully.