Radiator Valve Sizes

[AWJD]

I tried to adjust the lockshield valve on my 15 year kitchen radiator and it started leaking. I therefore decided to replace it and thought this would be a straightforward job. Unfortunately, the thread on the old valve appeared to be about 1" in diameter as was the nut on the radiator outlet.

I went round to our local Graham Plumbing merchant and nobody there seemed to have ever come across a radiator with this size valve before. If I can't find a suitable valve or converter then this radiator will need to be replaced which seems a little bit drastic.

Is the world going mad or is there a plumber out there who can offer me a solution?

 

[rocketmanbkk]

Post a pic of the valve. You might need. Valve & rad tail

A pic will tell a thousand words

 

[Chalked]

Most new radiator valves are 1/2 inch, thread/ 15mm copper. You have a union type radiator valve. These are 1". The trouble is that there are lots of different types of these, so you are better off removing the tail ( the bit in the rad) and use the tail that comes with a new valve.

 

[COHIBA1207]

Hi 3/4" on domestic is normally the biggest on a rad this age
Commercial valves can be bigger for black iron fitting
try using brass bushes or reducers to get to the correct size if there is enough room on the pipework
use a good seal prob PTFE as bushes and reducers are often not tapered

 

[turnpin]

Welcome AWJD to the forum's......any chance of a picture of the valve as it could be helpful with your enquiry.....regards Turnpin :welcome:

 

[ShaunCorbs]

Hi 3/4" on domestic is normally the biggest on a rad this age
Commercial valves can be bigger for black iron fitting
try using brass bushes or reducers to get to the correct size if there is enough room on the pipework
use a good seal prob PTFE as bushes and reducers are often not tapered

It's a lockshield Union mate

 

[rpm]

Hi 3/4" on domestic is normally the biggest on a rad this age
Commercial valves can be bigger for black iron fitting
try using brass bushes or reducers to get to the correct size if there is enough room on the pipework
use a good seal prob PTFE as bushes and reducers are often not tapered

Welcome to the forum.

Bit of an over kill isn`t? Bushes and fittings can be parallel or tapered threads and easy for an amateur to get wrong.

 

[AWJD]

I attempted to load a picture of the valve via the 'Image' icon but, after selecting the file, the update file(s) link didn't work. Could someone please explain what is going wrong?

 

[AWJD]

Not sure the upload of the picture worked but if it did it shows the Lockshield valve with 1" thread. .

 

[ShaunCorbs]

Stnd drain off lockshield, if it's leaking where the ptfe tape is wants some compound on it

 

[king of pipes]

Take the picture on your phone to screwfix with you they sell them fitted one today it's a standard valve bud

 

[rpm]

Isn`t it an O-ring to make the seal?

 

[ShaunCorbs]

Isn`t it an O-ring to make the seal?

No mating surface like big gate valves

 

[AWJD]

This valve has reached the end of its life and was leaking underneath where it's now covered in black RTV silicon. As said, the problem in replacing it is that it appears to have a 1" thread on the radiator outlet which must have been common when I fitted it 15 years ago. This size fitting no longer seems to be available unless someone knows better?

 

[ShaunCorbs]

This valve has reached the end of its life and was leaking underneath where it's now covered in black RTV silicon. As said, the problem in replacing it is that it appears to have a 1" thread on the radiator outlet which must have been common when I fitted it 15 years ago. This size fitting no longer seems to be available unless someone knows better?

We have told you it's a stnd lock shield drain off

http://www.NoLinkingToThis/p/chrome...ff/36552#product_additional_details_container

 

[snowhead]

Isn`t it an O-ring to make the seal?

No, taper

http://www.NoLinkingToThis/p/chrome-angled-radiator-valve-drain-off/70408

 

[johnf]

Its a common valve. We do know better and we are trying to tell you this :dizzy2:

 

[rpm]

No mating surface like big gate valves

When doing 6"- 18" gate valves there was a gasket, how do these seal then?

 

[ShaunCorbs]

When doing 6"- 18" gate valves there was a gasket, how do these seal then?

Just brass on brass mating surfaces

 

[rpm]

No, taper

http://www.NoLinkingToThis/p/chrome-angled-radiator-valve-drain-off/70408

Thanks snowhead, understand the taper there, meant under the nut ie usually expect olive or O ring.

 

[rpm]

Ok, got it. Little cross posting going on there.

 

[PlumbBobBob]

you need this from toolstation

http://www.toolstation.com/shop/Hea...762/Angled+Radiator+Valve+Drain+Off+CP/p40214

 

[ShaunCorbs]

you need this from toolstation

http://www.toolstation.com/shop/Hea...762/Angled+Radiator+Valve+Drain+Off+CP/p40214

That one is for 15mm think op has 10mm Pipework

 

[AWJD]

I have now been to both the main plumbing merchants in Abingdon (Grahams and Plumb Centre) and nobody in either had ever seen a Lockshield valve with drain with a 1" thread to the radiator. The guy in the Plumb Centre said he'd worked there for 25 years and never seen one even though my radiator is only 15 years old.

How come I can then walk into Screwfix of all places and buy one over the counter as recommended by you guys on the forum? It seems to be a standard size for Screwfix but to nobody else in the industry?

 

[ShaunCorbs]

I have now been to both the main plumbing merchants in Abingdon (Grahams and Plumb Centre) and nobody in either had ever seen a Lockshield valve with drain with a 1" thread to the radiator. The guy in the Plumb Centre said he'd worked there for 25 years and never seen one even though my radiator is only 15 years old.

How come I can then walk into Screwfix of all places and buy one over the counter as recommended by you guys on the forum? It seems to be a standard size for Screwfix but to nobody else in the industry?

Because it's not a 1" lockshield with drain off :banghead:

 

[AWJD]

It doesn't matter what the technical description for the valve is, I took the original one into the plumbing merchants and they said they had never seen one before with that sized thread on the radiator outlet!!

 

[rpm]

It doesn't matter what the technical description for the valve is, I took the original one into the plumbing merchants and they said they had never seen one before with that sized thread on the radiator outlet!!

You have a screwfix and a b&q in Abingdon suggest you try either of them, b&q will have them out on display.

 

[AWJD]

Because it's not a 1" lockshield with drain off :banghead:

I didn't say it was a '1" lockshield with drain off '. In fact it is a 10mm radiator valve with drain off which can be configured either as a lockshield or a manual valve as described on the packaging but it has a 1" thread on the radiator connection.

 

[ShaunCorbs]

I didn't say it was a '1" lockshield with drain off '. In fact it is a 10mm radiator valve with drain off which can be configured either as a lockshield or a manual valve as described on the packaging but it has a 1" thread on the radiator connection.

But that's not the rad connection, it's the connection on the Union

 

[rpm]

But that's not the rad connection, it's the connection on the Union

AWJD, it is made up of 2 parts, the 1st part screws into the radiator on a tapered thread then your valve connects from this part via the large nut to your 10mm pipe.

 

[AWJD]

My radiator came with the tail/unions already in place and that is what I was trying to connect a new valve to. What I was trying to understand is what are considered standard union thread sizes for these types of valve and why Screwfix do a 1" threaded connection to the union but proper plumbing merchants don't?

Fortunately, I've now got a replacement valve from Screwfix and so the problem is solved!

 

[rpm]

My radiator came with the tail/unions already in place and that is what I was trying to connect a new valve to. What I was trying to understand is what are considered standard union thread sizes for these types of valve and why Screwfix do a 1" threaded connection to the union but proper plumbing merchants don't?

Fortunately, I've now got a replacement valve from Screwfix and so the problem is solved!

Hurrah! :hurray: 😛arty:
I think the merchant was messing with you tbh.

 

[PlumbBobBob]

it is called 3/4" not 1" that's why

 

[rpm]

it is called 3/4" not 1" that's why

Which makes BSP so confusing to the unexperienced.

 

[Stoney Ground]

My radiator came with the tail/unions already in place and that is what I was trying to connect a new valve to. What I was trying to understand is what are considered standard union thread sizes for these types of valve and why Screwfix do a 1" threaded connection to the union but proper plumbing merchants don't?

Fortunately, I've now got a replacement valve from Screwfix and so the problem is solved!

What was the screwfix part number in case one of us guys come up against the same problem.

 

[AWJD]

I bought part 36552 from Screwfix. As said, I took the original valve into the 2 x plumbing merchants and neither had a size that matched. I'm going back to Screwfix tomorrow to get another valve for the other end of the radiator without the drain.

 

[AWJD]

it is called 3/4" not 1" that's why

I was referring to the diameter of the tread which was 1". And yes, this is also referred to as a 3/4" BSP thread- and the plumbing merchants still didn't stock it!

 

[rpm]

I bought part 36552 from Screwfix. As said, I took the original valve into the 2 x plumbing merchants and neither had a size that matched. I'm going back to Screwfix tomorrow to get another valve for the other end of the radiator without the drain.

Glad you got it sorted in the end however left wondering exactly what words you used ie did you say 1" for the radiator in which case I can understand the response you got.

 

[AWJD]

I needed to sort out the issues with my radiator valves because this summer I will need to get all the valves changed (TRVs included this time) and didn't want any nasty surprises in terms unavailable parts. My final understanding is the following:

1. All my old radiators and modern radiators use tails which all have a 1/2 BSP male tapered threads going into the radiator.

2. Therefore, since replacement valves come with a tail, it should be possible, worst case, simply to replace the old tails (and valves) with the new tails (and valves).

3. The old standard for valves was to use a 3/4 BSP union connection ('O' ring or fibre washer seal) to the radiator tail.

4. The new standard for valves is to use a 15mm compression connector to the radiator tail.

5. Many plumber merchants don't appear to stock radiator valves with union connections any more - fortunately, other outlets, such as Screwfix do stock them still.

This has been a bit of a steep learning curve for me, not helped by not knowing what correct terminology to use at times! However, I got there in the end!