Hi,
Is 15mm & 22mm copper pipe smaller than the old imperial 1/2" and 3/4" pipe.
I ask because I put a 22mm tee with 15mm branch onto a friends hot water pipe the other day using compression fittings and it leaked like a sieve. I did note that the existing pipes were a much thicker wall than the modern
1/2" to 15mm is no problem, just use a normal 15mm olive.. 3/4" to 22mm requires a special adapting olive. Decent hardware stores should stock them.
Allan
22mm copper pipe is actually slightly *bigger* than imperial 3/4". So if you put a 22mm compression fitting - with the supplied 22mm olive - onto a 3/4" pipe, it will likely leak. However, it's only a *bit* bigger, and you can get some special olives for using 3/4" pipe with 22mm fittings. [If using soldered joints, you need special fittings with a slight difference in size end to end for joining 3/4" to 22mm]. 15mm and 1/2" pipe are much closer in size and, although special fittings *do* exist, you can usually get away with using ordinary fittings inter-changeably - both with compression and solder fittings.
It may also be that it is indeed metric pipes but with a ticker wall. As the years have gone on and copper prices increased they have reduced the wall thickness. Outside diameter has stayed the same however. It does mean that you need a wee bit extra pressure to get olives to grip the older pipes and get a good fix. If you have some calipers or verniers then you could measure a new pipe against the old to ascertain whether its metric or imperial.
Good luck Calum
...or in the absence of a vernier gauge, I often close the jaws of an adjustable spanner around the pipe, and measure the distance with a rule.
Mark.
I couldn't get my normal compression to fit properly and the plumbers merchant had 16mm to 15mm compression adapters for this purpose. The bore on each end was a different size, since I did wonder if it was a marketing scam just with different olives ! Simon.
Had a word with the local builders merchants and they have the olives in stock so will be able to get some in the morning. Thanks again everyone
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