23mm Copper Pipe OD Reduction ?

jordo76

hi lads have a 23mm nut that wont fit over a 22mm pipe, the old 1 came off no problem but its like the pipe expanded and nothing new fits, is there a way to reduce the OD of the pipe ?? the oppisite side of the pump fits flawlessly
TIA

DublinDilbert

The pipe must have deformed and is stopping the nut going on. See if you can push on the body of a compression fitting, this should get the pipe back in shape. When you push on the compression fitting run it around the pipe to help bring it back true.

my3cents

You sure its a 22 mm nut and not an ever so slightly smaller 3/4 inch one?

my3cents

I can see the pump adapter clearly has 22mm written on the side of it. Forget the nut for a minute and see if the pipe fits into that (without the nut). The fitting is more accurately machined to just slightly larger than the pipe size than the nuts normally are, so if it fits the pipe is the right size or at least less than 22mm so it might just be you need a different nut. The nut should of course have 22 written on it and not 3/4.

The only time I've had pipes over sized is when they have been frozen but I doubt that is the problem here.

John.G

my3cents wrote: »

I can see the pump adapter clearly has 22mm written on the side of it. Forget the nut for a minute and see if the pipe fits into that (without the nut). The fitting is more accurately machined to just slightly larger than the pipe size than the nuts normally are, so if it fits the pipe is the right size or at least less than 22mm so it might just be you need a different nut. The nut should of course have 22 written on it and not 3/4.

The only time I've had pipes over sized is when they have been frozen but I doubt that is the problem here.

I just measured a bit of "3/4" copper piping lying around since ~ 1990 and its OD is 21.1 MM (ID 19.0 MM), I also measured a (stamped) 3/4" elbow bore and it is 21.22 MM, the 3/4 ins nut is 21.28 MM.

jordo76

lads i feel like a proper donk of course you were right about the size i took it as 22mm as the measurement was mm but of course in the new nut it is 21mm

cheers for the help lads

my3cents

No problem I won't have known the answer if I hadn't done the same myself

rightjob!

If thats the top of an ideal classic boiler and you are changing the pump it is 22mm,you will need 22mm pump valves

jordo76

anyone know a supplier down south just been into dpl and he said id have to north as there uk pipes

my3cents

Just use the old nut they all fit on the thread of the body of the fitting the same 3/4 will screw on to a 22mm fitting and vice versa.

However as you are discovered a 3/4 inch nut won't fit a 22 mm pipe and neither will a 22 mm olive so all you probably need is a 22 mm olive.

B&Q used to confuse people by selling 15 mm and 22 mm fittings in Ireland (we use 1/2 and 3/4 inch for the most part) so I suspect you'll get 22 mm fittings there, also Woodies.

John.G

my3cents wrote: »

Just use the old nut they all fit on the thread of the body of the fitting the same 3/4 will screw on to a 22mm fitting and vice versa.

However as you are discovered a 3/4 inch nut won't fit a 22 mm pipe and neither will a 22 mm olive so all you probably need is a 22 mm olive.

B&Q used to confuse people by selling 15 mm and 22 mm fittings in Ireland (we use 1/2 and 3/4 inch for the most part) so I suspect you'll get 22 mm fittings there, also Woodies.

Re the OP's "21 mm nut", can you buy a 21 mm fitting? or is this just the metric equivalent of 3/4"?

my3cents

John.G wrote: »

Re the OP's "21 mm nut", can you buy a 21 mm fitting? or is this just the metric equivalent of 3/4"?

Its a reference to 3/4" I went through my scrap box and threw a load of stuff out and I was surprised at how many old fittings I had with 21 written on the nuts so bothered to check as far as noting that they fitted over 3/4 inch pipe but not 22 mm pipe. But in the same test I found one nut marked 3/4 that fitted fine over 22 mm pipe so you can never be 100% sure. I'm a bit cynical about everything so find myself double checking. In my local builders merchants you can pick out your own fittings and the bins on the wall for 3/4 inch always have a few loose 3/4 inch and 22 mm olives and nuts plus some obviously mixed up fittings so someone is going to get the wrong ones without realising some times.

John.G

my3cents wrote: »

Its a reference to 3/4" I went through my scrap box and threw a load of stuff out and I was surprised at how many old fittings I had with 21 written on the nuts so bothered to check as far as noting that they fitted over 3/4 inch pipe but not 22 mm pipe. But in the same test I found one nut marked 3/4 that fitted fine over 22 mm pipe so you can never be 100% sure. I'm a bit cynical about everything so find myself double checking. In my local builders merchants you can pick out your own fittings and the bins on the wall for 3/4 inch always have a few loose 3/4 inch and 22 mm olives and nuts plus some obviously mixed up fittings so someone is going to get the wrong ones without realising some times.

Thats interesting because I have a (stamped) 22 mm gate valve which will take 3/4 ins pipe because its bore(s) is 21.2 mm but I always thought that metric pipe was measured by its OD, ie, 22 mm copper pipe is 22 mm OD and ~ 20 mm ID? so how can this gate valve take 22 mm piping?.

rightjob!

Any heat merchants or chadwicks should have them.

jordo76

cheers for the help lads got that part sorted all fitted and what do ya know a pin hole of a leak coming from the back of the nut
Feeling like getting a gallon of petrol at this stage

jhenno78

Hey OP, you've discovered the true joy of Irish plumbing - our unique pipe sizes.

We use 1/2" and 3/4" ID(copper) pipes, which are also called 14.7 and 21 mm (OD)

The UK uses 15mm and 22mm.

The threads for nuts use the BSP (British Standard Pipe) standard, both in Ireland, the UK and most of the world outside of North America. (ie. 1/2" and 15mm fittings used the same thread).

Because we're such a small market, fittings are much more expensive here and some parts harder to get. So, you get UK fittings turning up here.

Compatible? Well...
It's a common practice to fit Irish pipe onto UK fittings by adding an Irish olive, a big bit of tape and hooking it up. IMO it's a bit "sure f**k it, t'il be grand" and will be more prone to leaking (especially if it isn't well supported), but there's no denying that most of the time it doesn't cause trouble.
"User error" is a more likely cause of a leak (eg. over-tightening the nut).
I'd be a lot more hesitant doing this with 3/4" than 1/2".

Where it's threaded fittings mating there should be no trouble - they're the same size.

Ideally, you'd pipe 22mm into the fitting, attach a 22mm->3/4" connecter and then off to the rest of the run. Getting the tiny bit of 22mm pipe is the annoying bit here. Up to you.
(Edit: presumably attaching 3/4"female to compression coupling or a 3/4" female socket and a 3/4" straight coupling would work fine too and be handier).

John.G

jhenno78 wrote: »

Hey OP, you've discovered the true joy of Irish plumbing - our unique pipe sizes.

We use 1/2" and 3/4" ID(copper) pipes, which are also called 14.7 and 21 mm (OD)

The UK uses 15mm and 22mm.

The threads for nuts use the BSP (British Standard Pipe) standard, both in Ireland, the UK and most of the world outside of North America. (ie. 1/2" and 15mm fittings used the same thread).

Because we're such a small market, fittings are much more expensive here and some parts harder to get. So, you get UK fittings turning up here.

Compatible? Well...
It's a common practice to fit Irish pipe onto UK fittings by adding an Irish olive, a big bit of tape and hooking it up. IMO it's a bit "sure f**k it, t'il be grand" and will be more prone to leaking (especially if it isn't well supported), but there's no denying that most of the time it doesn't cause trouble.
"User error" is a more likely cause of a leak (eg. over-tightening the nut).
I'd be a lot more hesitant doing this with 3/4" than 1/2".

Where it's threaded fittings mating there should be no trouble - they're the same size.

Ideally, you'd pipe 22mm into the fitting, attach a 22mm->3/4" connecter and then off to the rest of the run. Getting the tiny bit of 22mm pipe is the annoying bit here. Up to you.
(Edit: presumably attaching a 3/4" female socket and a 3/4" straight coupling would work fine too and be handier).

Have you any thoughts on my quote from my post #13... "I have a (stamped) 22 mm gate valve which will take 3/4 ins pipe because its bore(s) is 21.2 mm but I always thought that metric pipe was measured by its OD, ie, 22 mm copper pipe is 22 mm OD and ~ 20 mm ID? so how can this gate valve take 22 mm piping?."

jhenno78

John.G wrote: »

Have you any thoughts on my quote from my post #13... "I have a (stamped) 22 mm gate valve which will take 3/4 ins pipe because its bore(s) is 21.2 mm but I always thought that metric pipe was measured by its OD, ie, 22 mm copper pipe is 22 mm OD and ~ 20 mm ID? so how can this gate valve take 22 mm piping?."

I'm not sure I get you?
It's an english fitting so it'll take Irish pipe because the Irish pipe is slightly smaller.
I'm guessing you haven't put actual 22mm into it? (not exactly something to keep knocking around)

John.G

jhenno78 wrote: »

I'm not sure I get you?
It's an english fitting so it'll take Irish pipe because the Irish pipe is slightly smaller.
I'm guessing you haven't put actual 22mm into it? (not exactly something to keep knocking around)

If its a english fitting stamped 22 mm why can it not take 22 mm piping?

jhenno78

John.G wrote: »

If its a english fitting stamped 22 mm why can it not take 22 mm piping?

Ah, in that case I'd guess they make Irish and UK fittings in the same factory.
They just bore out the fitting to a different diameter and don't bother with a different casting (fair enough I guess, it makes no difference).