What kind of radiator valve?

[ort67]

Hi, I need to replace a seized radiator valve, but I'm not sure what valve to use if someone can point me in the right direction?

I bought the valve listed below to replace it:

https://www.screwfix.com/p/white-chrome-angled-trv-with-lockshield-15mm-x/31811

But when I compare the two, the side that connects to the pipe looks the right size, but the male end that connects into the radiators female connection looks much thinner than the exiting valve.


Please see a picture of the existing valve shown below:


View media item 100974

 

[terryplumb]

Looks like they are same 1/2 inch bsp threads to me.

 

[ort67]

Looks like they are same 1/2 inch bsp threads to me.

So do you think that one I bought is the wrong size? It says it's 15mm x 1/2'', should I be looking for a 1/2'' x 1/2''?

I just went and measured it I think it's 1 inch by 15mm.

 

[terryplumb]

I am referring to the tails that go straight into the rad .the bit you measure at 1 inch diameter ,is actually 3/4 inch bsp thread ,and is the Union. I.e the joint between the valve body and the tail. The 15 mm relates to the pipe size end. The pair of screwfix valves in your link are different to one another ,and fine as a pair on a rad.

 

[ort67]

I am referring to the tails that go straight into the rad .the bit you measure at 1 inch diameter ,is actually 3/4 inch bsp thread ,and is the Union. I.e the joint between the valve body and the tail. The 15 mm relates to the pipe size end. The pair of screwfix valves in your link are different to one another ,and fine as a pair on a rad.

ok thanks, what type of valve do you think I should buy?

 

[terryplumb]

The valve currently on your rad is a lockshield .the link you posted re screwfix , is two valves . one is a lockshield ,exactly what you need as a replacement. The other is a trv ,which you can fit or keep as a spare. As you like.

 

[ort67]

The valve currently on your rad is a lockshield .the link you posted re screwfix , is two valves . one is a lockshield ,exactly what you need as a replacement. The other is a trv ,which you can fit or keep as a spare. As you like.

Cheers, I forgot to mention that both valves on the radiator are seized so I bought that to replace both sides. There are lock shields on both sides of every radiator in my flat, no TRVs at present.

 

[terryplumb]

Show pic of the other valve on your rad please .the trv you have may not marry up ,unless you remove the tail from the rad and fit the one that comes with the trv. Its good practice to fit the lockshield on the return pipework ,and the trv on the flow ( flow is the pipe on rad that heats up first when c/ heating is turned on ) ,although its not essential.

 

[ort67]

Here is a picture of the other side, they both look the same to me?

View media item 100975

 

[terryplumb]

They are both the same. Screwfix code 33920 , two of them would be direct replacements. Or as said earlier if you want to fit the trv ,you can ,but its a bit more work !!

 

[ort67]

They are both the same. Screwfix code 33920 , two of them would be direct replacements. Or as said earlier if you want to fit the trv ,you can ,but its a bit more work !!

Do you think it would be ok to reuse the existing adaptor on the radiator with the new valve? Maybe just renew the o ring?

Same with the olive on the pipe, do you think that it would be ok to reuse that? Or would it be better to try and knock the olive off the pipe and fit the new one? I've read some places that the inside of valves can be different sizes so sometimes it can be better to renew the olive. If I couldn't get the olives off then I might have to reuse it.

 

[terryplumb]

Best practice would be fit the new valves / olives, / nuts entirely. Having said that the valve to existing rad tail and captive ( existing) nut , will most likely be OK. The nut and olive on the supply pipes MAY be OK ,but the thread needs to be the same as on your new valve ( and most are 1/2 inch bsp ) and the olive and pipe need to be in good condition .

 

[ort67]

Best practice would be fit the new valves / olives, / nuts entirely. Having said that the valve to existing rad tail and captive ( existing) nut , will most likely be OK. The nut and olive on the supply pipes MAY be OK ,but the thread needs to be the same as on your new valve ( and most are 1/2 inch bsp ) and the olive and pipe need to be in good condition .

Looking online at vidoeos and old forumn posts there is conflicting advice, someone say it's ok to reuse exiting tails and olives some say replace them, some say use joining compound some say use PTFE tape.

See here Mr Plumberparts raps some PTFE tape around the olive at reuses it:

Here Mr Dereton33 slaps on joining compound:

There is another video of Plumberparts reusing the olive and tail, but I can't find it just now.

Is reusing them being lazy and bodging it a bit? More chance of leakage?

 

[terryplumb]

Compression fittings on copper pipes need only the olive to be compressed by tightening up the nut. Nothing else required ,as long as the olive and pipe are in good condition. PTFE tape is used on thread to thread joints ,sometimes with paste ,to seal between the threads. Having said all that ,you are working on a " second time around" joint ,and going to re use on a new valve ,so not quite the same really. Only you can see the condition of yours ,once the joints are separated .a few wraps of PTFE on the olive ,on the face that marrys up to your valve won't do any harm .

 

[ort67]

Compression fittings on copper pipes need only the olive to be compressed by tightening up the nut. Nothing else required ,as long as the olive and pipe are in good condition. PTFE tape is used on thread to thread joints ,sometimes with paste ,to seal between the threads. Having said all that ,you are working on a " second time around" joint ,and going to re use on a new valve ,so not quite the same really. Only you can see the condition of yours ,once the joints are separated .a few wraps of PTFE on the olive ,on the face that marrys up to your valve won't do any harm .

I tried to fit the new valve but the new tail is shorter than the old one by 4-6mm (difficult to get exact), and they have a different coupling so I can't use the old one, see below picture:

View media item 101001
View media item 101000
I've seen these extensions at the toolstaion website:

https://www.toolstation.com/shop/He...Valves/sd2762/Radiator+Valve+Extension/p37352

Do you have any tips of what the best thing to do is? Why can't manufacturers make things the same size, I can't really move the pipes coming from the floor. I can't see anything suitable at screwfix.

I saw on another forum that these extensions can be difficult to seal:

https://www.ukplumbersforums.co.uk/threads/leaking-rad-tail-extensions.98528/