Old westherm trv head broken- trying to replace

[Flower0503]

Hi, I have a radiator where the trv head is broken. I'm trying to source a replacement, but struggling to find- the thread is larger on modern heads
Are trv heads with the smaller threads still available (and if so where from??) Or can you get adaptors (and if so how do you work out what size to get?)

Here is a picture of the trv head- hoping that someone else has had this problem and solved it before (or that Piglet John may know) Thank you in advance

Try here www.westherm.co.uk/

Browse as many plumbing suppliers as you can and see if you can find one that looks the same.
Start with outlets in your own town or nearby, and Screwfix, Toolstation, B&Q.
but...

it is not very difficult to remove the old and fit a complete new valve, unless the pipes come up through a concrete flooe and have no movement on them (different valves may be a different length), when you need an experienced plumber. A tip: you can move the rad up and down a bit by lifting it off its brackets and refixing the brackets, with new screws, a bit higher or lower. It is also possible to file the slots a bit to move the rad slightly down. If your boiler has a pressure gauge it should not even be necessary to drain or bung the system.

My favourite is the RAS C2

Hi, that's great thank you😀 I've sourced the part/ product code that will replace it (westherm 5 head 05428 or 05423), I'm just struggling to find where to buy it from. Local plumbing places seem to stock the westherm 6 and won't order the 5in. I've seen some on eBay but with slightly different codes, so no idea if they are suitable or not!give contacted westherm to see if the eBay product codes are suitable or not...

I'm reluctant to change the valve as I can't drain the radiator- it has rusted at the bleeding valve. There are another 3 radiators that I can't bleed either, so just trying to hold out before we replace the whole lot (which there is no way my husband will agree to this year). So just want to replace the trv head until we can sort the whole house heating.

You can replace the thermostat head without removing the rest of the valve or draining the heating system. As you have found (per your photos) you just unscrew the thermostat head from the valve.
The challenge comes in getting the right size fitting on the thermostat. Some older valves have a 28mm diameter fitting, whilst newer ones are 30mm. Screwfix sell the 30mm ones very cheaply. You may struggle to find a 28mm fitting. It seems there are companies selling adapters to convert from 28 to 30mm. Suggest you take your thermostat head with you to the plumbers merchant so you can check what size you have. (Benefit of buying in person rather than online!)

Hi, did you ever manage to find a supplier for the Westherm thermostat? I have been on the lookout for some weeks but without success.
Thaks

I bought this which worked if any use

www.ebay.co.uk/itm/Westco-Angled-Westherm-5-With-Solar-Lockshield-/163091464089?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=710-127635-2958-0

Thanks a million for the prompt response. I have just ordered one which should be with me in a few days.
Cheers