Is there an old equivalent of 22mm copper pipe that may be slightly smaller? Just had a hell of a day trying to get compression joints to seal and realised that the main problem areas have been where I've re- used some old pipe recovered from under the floor. It's an old house.

Thanks

Yes there is but compression joints should still work for it. If you can get one good join and then stick with 22mm you should have fewer issues.

Also, push fit plastic piping is not evil, does work even for central heating and is A LOT easier for non-plumbers.

The old stuff is imperial 3/4" diam which is a fraction smaller than the 22mm.

Big bear has it

Thanks chaps.

I usually use plastic pipe actually but a friend suggested copper is more mouse-proof. Think I'm back to the shop tomorrow.

Does the same apply to old 15mm? An imperial equivalent – 1/2"?

Didn't realise you're a plumber Paul

Same as what I said. A bit of PTFE tape and compression should be okay but never good. Get one good joint between the two pipe sizes, preferably where you can get to it easily when it starts leaking. Use one size of pipe after that one good connection and you will be fine.

you should be able to buy a 3/4" olive to fit in a standard compression fitting.

15mm and 1/2" are so close in size that they will interchange quite happily on soldered or compression. Wouldn't risk it on push fit though.

Yep you can get appropriate olives to fit,there called green rings round these parts.

Am I the only one who thinks waynekerr discussing green rings round his parts sounds a bit dodgy 😕