Connect old rad valves to new rad

[TonyQJ]

Hi Guys. Sorry for such a long first post.

We have a 24 year old 10mm microbore ch system and on the advice of a plumber I’m going to change the rads a room at a time, as and when we decorate, to slowly achieve a more efficient system. I’m aware that modern metric rads will require an extender to get from the valve to the rad, but herein lies my problem.

The existing valves terminate in a 25mm male thread, with the rad tails (obviously) having a matching female. Modern rad tails, valves and valve extensions all appear to be 15mm. To replace the existing rad valves would require draining the system down every time I wish to change a radiator, so...

Is there such a thing as a Chrome 25mm extension tail? If not, does anyone have a suggestion that doesn’t involve changing the valves?

Thanks in advance for any advice.

Ps. When I say “25mm” that’s measuring across the thread with a tape.

 

[SimonG]

It will be 3/4".

Any pics?

 

[TonyQJ]

Pics:
Lock shield 1, lock shield 2, Radiator tail

 

[Riley]

3/4

 

[Harvest Fields]

As above

 

[TonyQJ]

So... is there such a thing as a 3/4” extender? I’ve not had much luck with my Googling.

 

[Riley]

Try a proper plumbers merchant

 

[ShaunCorbs]

Need to pull the the fitting out the rad then use 1/2 extensions from the fitting to the rad

 

[Riley]

Need to pull the the fitting out the rad then use 1/2 extensions from the fitting to the rad

1/2 - 3/4 extension pieces?

 

[Harvest Fields]

Toolstation. Is this any good?

 

[Harvest Fields]

1/2 - 3/4 extension pieces?

You can get them but I’m sure online only. Not seen a proper 1/2” x 3/4 extension. On 1/2 x 1/2”

 

[ShaunCorbs]

1/2 - 3/4 extension pieces?

Remove the rad tail out then it’s 1/2 both sides

 

[Harvest Fields]

Like my picture @ShaunCorbs ?

 

[TonyQJ]

Thanks all...

Plumbers merchants - I’ll try tomorrow if no joy on here.

Pull the fitting out of the old rad - that would work I think, which leads on to my next question - how? It has an internal hex about 12mm across the flats, does the tool for this have a specific name?

Toolstation - I cant see how that piece would help me.

 

[Riley]

https://www.NoLinkingToThis/p/radia...YUIl0X0VI3q5LJqM8txoCpQ0QAvD_BwE&gclsrc=aw.ds

 

[Harvest Fields]

If you cannot then if I was you I wouldn’t be fitting the radiator. That is your extender.

 

[Harvest Fields]

You need a rad spanner and some loctite also.

 

[TonyQJ]

Need to pull the the fitting out the rad then use 1/2 extensions from the fitting to the rad

https://www.NoLinkingToThis/p/radia...YUIl0X0VI3q5LJqM8txoCpQ0QAvD_BwE&gclsrc=aw.ds

Perfect. Many thanks 😉

 

[Riley]

Or just change the valves to 15mm-1/2

 

[Harvest Fields]

Or just change the valves to 15mm-1/2

Far too easy that mate😛😛

 

[TonyQJ]

Or just change the valves to 15mm-1/2

But as I wrote in the OP that would mean draining down the system every time I change a rad.

 

[SimonG]

1/2" in the rads.

Rad spanner, unscrew them, clean them and use whatever size extender and then screw back in.

 

[ShaunCorbs]

Like my picture @ShaunCorbs ?

Correct

 

[Harvest Fields]

Correct

Cheers for the recognition mate. Thought I was going mad for a minute then.

 

[TonyQJ]

You need a rad spanner and some loctite also.

Yep thanks. Bought the rad spanner, got the fittings out and will clean them up. Already got the Loctite 🙂

 

[Harvest Fields]

Yep thanks. Bought the rad spanner, got the fittings out and will clean them up. Already got the Loctite 🙂

Hope all goes well mate. 😉😉

 

[DjClubber]

You still need to drain off.

 

[ShaunCorbs]

You still need to drain off.

Not with extensions

 

[DjClubber]

To Change The Whole Valve To TRV???

 

[Riley]

But as I wrote in the OP that would mean draining down the system every time I change a rad.

But then you would have a nice shiny new valve on each rad?? You could try bunging it if it’s an open vent system

 

[ShaunCorbs]

To Change The Whole Valve To TRV???

Leave the existing valves

 

[DjClubber]

I misread, connect old valves to new rad. I thought old rad to new Valves. Im bad...

 

[Harvest Fields]

I misread, connect old valves to new rad. I thought old rad to new Valves. Im bad...

As you’ve admitted it you can be forgiven.😛😛

 

[Riley]

As you’ve admitted it you can be forgiven.😛😛

This time

 

[TonyQJ]

But then you would have a nice shiny new valve on each rad?? You could try bunging it if it’s an open vent system

Only just recently had a Brit Gas bod here for two days, re-plumbing the airing cupboard, rodding out some pipes, replacing some plastic with copper, loads of upstairs floorboards up, fitted a filter and treated the system. It was he who recommended replacing the rads one by one as and when. This is the first one I’m changing. Yes it’s open vented but I’m wary of messing with the system too much now that he’s got all rads working again. I know I could tie up the ball valve in the loft, drain it all down and then add inhibitor before releasing the ball valve again but as I say, I’m wary of messing with it. I’m happy with the old valves at this stage. I could always change them all in one go at some time in the future.

Thanks for the suggestions though 🙂

 

[Riley]

Only just recently had a Brit Gas bod here for two days, re-plumbing the airing cupboard, rodding out some pipes, replacing some plastic with copper, loads of upstairs floorboards up, fitted a filter and treated the system. It was he who recommended replacing the rads one by one as and when. This is the first one I’m changing. Yes it’s open vented but I’m wary of messing with the system too much now that he’s got all rads working again. I know I could tie up the ball valve in the loft, drain it all down and then add inhibitor before releasing the ball valve again but as I say, I’m wary of messing with it. I’m happy with the old valves at this stage. I could always change them all in one go at some time in the future.

Thanks for the suggestions though 🙂

If that’s your thought then look at bunging the f&e tank. Then you’ll be able to remove the valves one at a time as you replace the rads

 

[TonyQJ]

If that’s your thought then look at bunging the f&e tank. Then you’ll be able to remove the valves one at a time as you replace the rads

Thanks for the suggestion. I’ll give it a try next time 🙂

 

[fixitflav]

Thanks for the suggestion. I’ll give it a try next time 🙂

I don't see the problem. As you're happy to keep the valves, you can isolate the rad so you don't need to drain the system. Obvs a radful will come out, catch as much as much as you can, to minimise mess and so you can return it to the F/E tank (after settling out any sludge). Unscrew and re-use the rad tails with your new spanner. If the new rad is the same length, you should be able to screw the tails in so the overall length is the same, but there's likely to be a few mm play in the pipes anyway. If to get the right length you need to stop before the tail is dead tight you might be better off with PTFE tape (plenty of it) rather than paste, but the pros here might correct me on that.

 

[TonyQJ]

I don't see the problem.

There isn’t one. I’m doing exactly as you suggested in the rest of your post.

My response to Riley was with regard to changing the valves.

 

[fixitflav]

There isn’t one. I’m doing exactly as you suggested in the rest of your post.

My response to Riley was with regard to changing the valves.

OK thanks. If you do eventually drain down and change the valves, I'm sure you won't do it this time of year, wait till the summer!

 

[TonyQJ]

I’ve only just realised that I rudely never updated this thread.

Using my shiny new radiator spanner I was able to swap the tails from the old rad to the new, connect up with a sliding extender on one end and the job was a good ‘un. Thanks for the help guys 🙂

 

[Scott_D]

Are you keeping 24 year old valves?

 

[TonyQJ]

Are you keeping 24 year old valves?

Yup. For now at least. It’s not like they do any work.

 

[Scott_D]

Yup. For now at least. It’s not like they do any work.

Well the usually leak if you use them.
Add TRVs to Update the system and increasing efficiency