Discuss What size is this rad/valve connection? picture included in the Plumbing Jobs | The Job-board area at PlumbersForums.net

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Hi all.

I'm removing the rad in the picture for decorating and want to blank off the connection from the thermostat/valve to the rad (will do both ends obviously). The thermostat/valve has 1/2 bsp stamped on it but pretty sure the connection to the rad is not 1/2 bsp, I have a couple of 1/2 bsp blanking caps but these are too small. Does anyone know what size the connection to the rad is?

Many thanks in advance.
Stuart

IMG_1084.JPG
 
I would say that is 1/2 inch.

How do you know that what you have is too small, have you tried to
fit it?
 
I would say that is 1/2 inch.

How do you know that what you have is too small, have you tried to
fit it?
I haven't tried to fit it yet but the 1/2 bsp fitting I have looks way too small when offered up against what you see in the picture. Spanner size is also smaller on the 1/2 bsp fitting I have.
 
this is what you need

15mm

the 1/2 refers to the connection to the pipe
 
Many thanks Shaun. I figured that that was the case but had no way of sizing the connection. I'll get a couple before taking the rad off. Thanks again, Stuart
 
note that wont work for the pipe end if your removing the trv
 
That trv & lockshield will be quite a few years old so may have a bit of a seep especially the TRV head side.

Also that TRV variant only closes to the frost-guard (4 degree's approx) setting unlike the newer variants which goes to full shut-off, something to bear in mind at this time of year.

Some towels around bottom of pipes are also a good idea if carpet is fitted to stop potential staining.

Good luck,

Andy
 
Ok, so I've bought a couple of the blanking nuts that Shaun kindly gave the link for but these are too small as well. I've not actually tried to fit them but when you offer them up they look way too small. Could the rad connection be 22mm? As you can see in the pic the pipe work is 15mm but I'm clutching at straws here a bit. Plasterer coming on Monday and I need this rad off and the connections blanked. Any thoughts anyone?

Many thanks in advance
Stuart
 
It should fit as it's a standard 15mm nut and olive
 
I hear what you're saying Shaun but they're too small. Just to clarify, I'm talking about the connection/union between the trv and rad. Given that the trv is deffo 1/2 bsp as it's stamped on it, shouldn't the union also be imperial and not metric. The union is obviously bigger than 1/2 bsp, so could it be 3/4 bsp?
 
Surely the cap that Shaun is in about screws straight onto the valve not the tail for the radiator?
 
Surely the cap that Shaun is in about screws straight onto the valve not the tail for the radiator?

Correct

If it's the tail end you want op it's a 1/2 cap you need
 
But I've already tried 1/2 and it's too small. Could the union be 3/4 bsp?

On the parts what's inside the rad ? And defo won't be
 
Take the rad off and the nut will slide off the tail, (the bit in the rad)
Once you have the nut, put a 5p inside it and then a 1/2" tap washer and use that!
That's what I always do and it never fails.

finger tight will do, maybe a 1/8th nip, I always open the valve to make sure it doesn't leak.
 
Take the rad off and the nut will slide off the tail, (the bit in the rad)
Once you have the nut, put a 5p inside it and then a 1/2" tap washer and use that!
That's what I always do and it never fails.

finger tight will do, maybe a 1/8th nip, I always open the valve to make sure it doesn't leak.
So your the one:p:p:p:p
 
Install 5p coin as blanking disc;

I prefer:-
Provide and install Coin of the Realm depicting a portrait of Queen Elizabeth the second. The coin is professionally set upon a Black Vacca washer which is artistically embossed with the words '1/2" Vacca'
 
Maybe that valve has the large flange tail?
Was more common on the older TRVs and on the valves with option for copper or iron pipe, which that is.
The photo is difficult to judge, but the more I look at it, the more I am sure that tail nut is the large type.
 
I prefer:-
Provide and install Coin of the Realm depicting a portrait of Queen Elizabeth the second. The coin is professionally set upon a Black Vacca washer which is artistically embossed with the words '1/2" Vacca'

You really should always do all your work to a gold standard and use a gold half sovereign.
Expensive, but it will always impress the person that removes the blanking nut.
;)
 
Maybe that valve has the large flange tail?
Was more common on the older TRVs and on the valves with option for copper or iron pipe, which that is.
The photo is difficult to judge, but the more I look at it, the more I am sure that tail nut is the large type.

I agree. It is the older type TRV with a 1/2" female thread on the bottom that you could use with the male nut and a longer than standard olive provided or any other male BSP 1/2" thread.
 
I agree. It is the older type TRV with a 1/2" female thread on the bottom that you could use with the male nut and a longer than standard olive provided or any other male BSP 1/2" thread.

So do you think the tail is the large nut type?
I carry the large tails with a female fitting on them for draining from radiator valves or blanking off radiator valves that are the larger type
 
So do you think the tail is the large nut type?
I carry the large tails with a female fitting on them for draining from radiator valves or blanking off radiator valves that are the larger type

Yes. I think the nut is the older thick walled one. The tails as I remember had threads that were cut across if you know what I mean. I used to look at them and wonder why. Do you know what I mean or will I need to find one and post a pic?
 
Yes. I think the nut is the older thick walled one. The tails as I remember had threads that were cut across if you know what I mean. I used to look at them and wonder why. Do you know what I mean or will I need to find one and post a pic?

Do you mean the fine cuts across the threads that I think were done for to allow the tape, or thread seal to grip and stay in place?
I think Westherm did similar valve.
Also Tower might have been similar
 
So...are we any closer to getting a definitive size for this union. I'm leaning to it being 3/4 bsp. The trv is deffo 1/2 and the union is deffo bigger than 1/2 as I've tried a 1/2 nut against it and it's way smaller. I can't see it being metric size, what with the trv being imperial. Anyone agreeing with me on this??
 
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