Radiator TRVs

[Keeping Up]

Does anyone know whether the top part of Thermostatic Radiator Valves is standardised or not? Can the top part from one manufacturer simply screw on to the bottom part of one from another manufacturer as a simple replacement?

 

One of mine still works fine as a valve (turn it fully one way and the radiator is fully on, turn it the other way and the radiator is off) but doesn't seem to function as a thermostat in any way. As it's almost 30 years old, a direct replacement seems unlikely although maybe the same manufacturer still exists if I can find a name anywhere on it. Simply exchanging the head would remove the need to drain and refill the system, so would be a lot easier.

[Hudds Lad]

we had an iffy one a few years back, BGas chap just unscrewed it and put on another from the back of his van, totally different manufacturer but same thread etc.

[Keeping Up]

2 minutes ago, Hudds Lad said:

we had an iffy one a few years back, BGas chap just unscrewed it and put on another from the back of his van, totally different manufacturer but same thread etc.

That's encouraging, thanks

[Guest]

2 minutes ago, Hudds Lad said:

we had an iffy one a few years back, BGas chap just unscrewed it and put on another from the back of his van, totally different manufacturer but same thread etc.

Same here. Our plumber changed one for us. but it wasn't thirty years old.

 

(It's also possible to change a radiator valve without completely draining the system, but it's a bit of a faff).

 

My late father in law once changed one for us doing this. There are some vids on You Tube.

[1st ade]

30 minutes ago, Keeping Up said:

Does anyone know whether the top part of Thermostatic Radiator Valves is standardised or not?

From experience - yes - but there are multiple "standards". I've swapped heads from one with the body of another without issues and had some which just don't mate.

 

It's also worth noting that a mechanical fit is not the only issue - I've ended up with a working head but it's range is "hot" to "warm" and can't be set to "cool" or "frost"

[Ex Brummie]

There are a few generic valves with many different names, so an experienced techie will recognise this. Post a picture and I may be able to advise.

[Keeping Up]

Thanks. Unfortunately I can't get on board atm because the boat is in dock having blacking and paintwork done, so I can't post a picture yet. Encouraged by these responses I will buy a cheap one from Screwfix to take with me next week; if it fits & works that's Job Done, otherwise it's on a 30 day return.

[Cas446]

5 hours ago, Keeping Up said:

Does anyone know whether the top part of Thermostatic Radiator Valves is standardised or not? Can the top part from one manufacturer simply screw on to the bottom part of one from another manufacturer as a simple replacement?

Have a look at this pdf. Although written by Drayton it summarises all the types.

 

https://wiser.draytoncontrols.co.uk/support/document/wiser-radiator-thermostat-adapter-guide

 

Edited October 1, 2020 by Cas446
Duff link

[Keeping Up]

That's really useful, thanks

[Martin Nicholas]

Electronic ones are pretty good:

https://ebay.us/dypVTl

I have Honeywell ones, no longer available I believe.

[phantom_iv]

18 minutes ago, Martin Nicholas said:

Electronic ones are pretty good:

https://ebay.us/dypVTl

I have Honeywell ones, no longer available I believe.

I swapped an old Honeywell for a Drayton head just last night.... seems to work.

 

I'm a little suspicious of the electronic ones as I had one that worked way too fast - the air around the radiator warmed up, electronic thermostat shut it down, leaving the rest of the room cold. I guess you could make it better with software, but not sure you achieve a huge amount over a mechanical one if you do. I solved the problem by linking the electronic one to an (expensive!) wall thermostat at the other side of the room, that controls the electronic one based on the temperature in the rest of the room.

 

On the other hand, they might work quite well in a smaller space such as a boat!