slight leak on old style pipes

[shabbaranks]

Hi guys

We've got a slight leak on a cold feed which initially came from a pin hole leak. Couldn't get anything around or cut the pin hole leak pipe so had to cut it further up and put some plastic pipe in.

This is fine but with the original pipe work (which is the old size copper) connecting to 15mm coupler's at either side - there is a slight dripping leak. Can I buy a coupler which is the old size on one side and 15mm on the other side? Found this on screwfix but wasn't sure if its the one (Im not a plumber just a keen enthusiast)

http://www.screwfix.com/p/female-coupler-15mm-x/93992#

Thanks!

 

[keego]

The difference between 15mm & 1/2" imperial is negligible & all 15mm fittings will fit it. If you've got a slight weep on the joint either give it the grip of death until it stops or undo the joint & put a few wraps of PTFE tape on the olive.
The fitting in your link is for adapting a 1/2" BSP fitting (usually steel) to copper.

 

[Blagard]

To clarify keego, a 15mm compression coupler will fit both 15mm copper and old 1/2" copper. If you use a soldered coupler then use the slightly stepped coupler
http://www.screwfix.com/p/solder-ring-imperial-metric-adaptors-15mm-x-pack-of-2/69948

 

[MANDATE]

In days gone by water was supplied in steel pipe. The size of the pipe went by the bore diameter. Pipe with 0.5 inch bore is has threads of 0.825 inch outside diameter, which is used for joining pipes using threaded couplings.
So a 0.5 inch BSP is a bit misleading.
When copper pipe was introduced joining together was by soldering, but it was still known by the bore size. Now 0.5 inch bore equals about 12.7 mm and with a wall thickness of 1mm make the outside diameter 14.7 mm.
The change from imperial to metric basically made no difference as far as 0.5 inch pipe. The nearest metric equivalent to 14.7 inch is 15mm.
So if you are joining old 1/2 inch steel pipe with threaded end to 1/2 inch or 15mm copper the coupling shown is OK.
The threads will need sealing in the form of PTFE tape or thread paste.
The opposite end of course is a compression fitting (don't over tighten)

 

[Madrab]

Yup, the old 1/2" pipe is ID whilst the new 15mm is OD so you're talking 0.2mm difference OD if I remember rightly.
As Keego says, a few turns of PTFE tape on the olive overlapping onto the copper pipe and a good nip up should do the trick.

 

[shabbaranks]

So a bit of ptfe should do the trick. Not being a plumber but speaking to a few Im always hesitant of tightening the joins up too much as I understand you can crush the olives which isn't good.

I was told wrench tight and a third or there about

 

[Blagard]

In days gone by water was supplied in steel pipe. The size of the pipe went by the bore diameter. Pipe with 0.5 inch bore is has threads of 0.825 inch outside diameter, which is used for joining pipes using threaded couplings.
So a 0.5 inch BSP is a bit misleading.
When copper pipe was introduced joining together was by soldering, but it was still known by the bore size. Now 0.5 inch bore equals about 12.7 mm and with a wall thickness of 1mm make the outside diameter 14.7 mm.
The change from imperial to metric basically made no difference as far as 0.5 inch pipe. The nearest metric equivalent to 14.7 inch is 15mm.
So if you are joining old 1/2 inch steel pipe with threaded end to 1/2 inch or 15mm copper the coupling shown is OK.
The threads will need sealing in the form of PTFE tape or thread paste.
The opposite end of course is a compression fitting (don't over tighten)

Ops - Old imperial 1/2" copper is bigger than 15mm that's why a standard 15mm coupler is so tight on the old stuff! Also olives which are generally loose on 15mm are a tighter fit on old copper

 

[MANDATE]

Tips
Use a copper olive instead of brass. Copper is softer.
If anything under tighten compression joints and tighten it as it leaks.
PTFE tape not required

 

[MANDATE]

In days gone by water was supplied in steel pipe. The size of the pipe went by the bore diameter. Pipe with 0.5 inch bore is has threads of 0.825 inch outside diameter, which is used for joining pipes using threaded couplings.
So a 0.5 inch BSP is a bit misleading.
When copper pipe was introduced joining together was by soldering, but it was still known by the bore size. Now 0.5 inch bore equals about 12.7 mm and with a wall thickness of 1mm make the outside diameter 14.7 mm.
The change from imperial to metric basically made no difference as far as 0.5 inch pipe. The nearest metric equivalent to 14.7 inch is 15mm.
So if you are joining old 1/2 inch steel pipe with threaded end to 1/2 inch or 15mm copper the coupling shown is OK.
The threads will need sealing in the form of PTFE tape or thread paste.
The opposite end of course is a compression fitting (don't over tighten)

Ops - Old imperial 1/2" copper is bigger than 15mm that's why a standard 15mm coupler is so tight on the old stuff! Also olives which are generally loose on 15mm are a tighter fit on old copper

Thanks for that! Can only be a couple of thou in it. I've not measured 1/2 copper and 15mm was not quite 15mm last time I checked it.

 

[Blagard]

Thanks for that! Can only be a couple of thou in it. I've not measured 1/2 copper and 15mm was not quite 15mm last time I checked it.

You're welcome
I usually have a couple of end feed adapter couplers in my kit box and I can't tell which end is which until I slip it on the pipes. The test is both ends slip on 15mm easy but only one end will slip on the old imperial with ease.