TRV's wont fit

[D.I.Why?]

I've bought a load of TRVs for my radiators (bl**dy fuel bills are killing me) The pipes are 15mm but the connection on the radiator is 1/2". Not a problem with the normal screw down Valves but the TRVs are 15mm all over. Looked at screwfix but they don't seem to make them the way I need.

Haven't got room for an adaptor...do the right size Valves exist and where do I get them?

Here's some pics to clarify my situation.
Cheers,
Brian.

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• D.I.Why?
• 15 Aug 2008
• 1

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• D.I.Why?
• 15 Aug 2008
• 1

(I know it looks a bit tatty but I use radiator covers )

 

[gas4you]

You cannot get trv's with a 3/4" union.

You will have to remove the tails of the old valves from the radiator and fix the new tails that come with the new trv's into the rads.

 

[AMEdinburgh]

From a DIYer not a plumber

I think all the 15mm TRVs will fit. You can remove the fitting from the radiator and use the ones from the new TRVs

Likely you'll need a big 12mm allen key to remove the rad outlets but screwfix will have that too.

If you study the pictures on Screwfix I think you'll see

 

[AMEdinburgh]

Sorry duplicated post - gas 4 you is quicker at typing than me!

 

[spacethegas]

look at the trvs you bought.
you will see that they will fit.

 

[D.I.Why?]

Yes, that was my initial thought. The Tails are even supplied in the boxes with the TRVs. However the hole the Tail goes into is still bigger than the 15mm Tail so I can't use them.

It might be hard to make out, but you can see the size/diameter of the existing Tail and where it fits onto the radiator in the photo.

...or am I still missing something obvious?

Thanks,
Brian.

 

[spacethegas]

i don't understand what your trying to say.

 

[kirkgas]

i think you are missing something, from the photo they look like "ordinary" valves, ie 1/2" BSP thread going into rad, you will need a radiator tail allan key to remove the tail then a spanner to fit the new tails into the rad then connect the valves

 

[buck51]

It looks like an 1/2" tail to me , Can you hold one of the new tails next to it and take a new photo and post it,

 

[JohnD]

when you unscrew that big union nut and take off the old valve, you will find the nut hangs loosely on the old tail. the old tail has a square, or octagon, or two nibs inside its throat, which you use to unscrew it from the rad with a radiator spanner

then you screw the new tails into the radiator. the new ones you can probably grip with an ordinary spanner.

easy peasy

 

[D.I.Why?]

Thanks everyone so far

Hope this helps.

Perhaps it's a lack of faith on my part, but it looks to me like the new tail won't screw into the hole I'll be left with when I remove the old one.

What do you recon?

Cheers,
Brian.

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• D.I.Why?
• 15 Aug 2008
• 1

 

[spacethegas]

have faith.

 

[JohnD]

measure the old tail and see if it seems to be 1/2" or 3/4"

(not the big nut)

 

[Andy165]

It will fit. Dont forget to ptfe the thread of the new tail. On some very very old radiators the boss were 3/4 inch so you could use a 3/4 inch to 1/2 inch reducing bush to adapt it

 

[D.I.Why?]

Lol You know what lads, your right... While I was taking that last picture I thought "I'm just gonna yark the thing out and if it fits, it fits - If it doesn't, it doesn't!"

Thanks for all the help... I'll pop out and get one of those allen keys tomorrow.

Cheers,
Brian.