Theromostatic radiator valve not working

[Punkstereo]

The TRVs I have don't work. Even when I switch all the way to zero setting on the TRV, the radiator is still as hot.

My guess is that they're the wrong fitting. I've scoured the Internet but can't get info on what is the correct fitting and product I should replace these with?

I have 3 of these TRVs on radiators at home and they all have the same issue.

 

[Punkstereo]

This is the fitting attachment. The TRV I got is Drayton RT212. Any help or advice on the correct product to get would be helpful.

I'm hoping that I don't have to swap out the entire valve components. Would prefer if just need to get a different TRV that I can just screw on myself

 

[kidgreen61]

Those look like Bulldog brand, as sold by Wolseley.
Will the pins in the valves move up and down (only 2-3mm)?

 

[kidgreen61]

Just seen your pic, I don't think those valves are Bulldog

 

[Punkstereo]

Drayton RT212?

I only just noticed these presumably temperature settings underneath. Anything I have to adjust with these perhaps?

 

[mcprinter]

I have RT212. Fitted in the last couple of years.
Mine look a bit different. Maybe a design change.

The pin looks a bit manky on yours. Will it move?

 

[mcprinter]

Drayton RT212?

I only just noticed these presumably temperature settings underneath. Anything I have to adjust with these perhaps?

They are for limiting the upper temperature range. Won't help with your problem.
Only DIY but suspect your system needs a clean and the valves are not seating, allowing water to flow.

 

[Mister Banks]

Check that the pin in the valves all move freely. Looks like the one in the photo is a bit crusty.