I Am about to fit a new radiator : the existing pipework that I am teeing off from is 1/2inch . Past experience has told me that I am not going to be able to use a 15mm end-feed tee as it will be too tight. ( I won’t know for sure untill I actually cut the pipe ) it measures 15.10mm My options are the use 1/2 inch to 15mm connectors and then use a 15mm tee . Or just use compression hopefully these will fit, as it’s under suspended wooden floor leaks will not be terminal . I am not asking how to do the job : rather some insight to how the trade would address this job before I make my decision. I am going to wait for warmer weather as I want to change some clapped out rad valves while I have it drained down These are very old so I’m guessing the threads on the valve nut are not going to fit my metric olive puller So may have to cut and snap the the olives off : won’t be able to leave them on as the threads on the nut will not match the threads on the new valves Ps thanks for all the advice on my previous post, regards my sons plastic speed-fit pipework we eventually opted the push on speed-fit fittings : all up and running : very easy I may now be a convert you never know .
I prefer to use a 1/2 inch to 15mm end feed joiner,not a fan of compression fittings under floors. Threads will still 1/2" or 3/4"BSP regardless of age of fitting.
App threads : thanks excellent . I’m still thinking about the pipe ..it is under a bungalow ground floor ( wooden suspended) so no danger of flooding the place. Would make the job easier.
KIAB I was more referring to the the cap nuts at the bottom of the valve, that secure the pipe to the valve . I could leave them on and use the original olives, I understand that with old valves the threads might not match the new ones + the threads on my olive puller. Just doing some homework while I wait for some warmer weather and get a pass to turn the central heating off.
You will be fine using a standard 15mm EF/SR fitting on old imperial pipe. The size difference is miniscule. 3/4 is a different kettle of fish though, where an imperial-metric fitting is definitely required.
Ok thanks As I said. just doing some homework I won’t know for sure untill i actually cut the pipe. Yes I measured some pipe with my micrometer and the 1/2 pipe was 15.10mm diameter And the 15mm measured 14.95mm
No problem connecting 1/2 inch to 15 mm copper! If tight rub down with sand paper. When you flux it that will lubricate it.
Some old 1/2" can be really tight,even rubbing down,if you have a socket former,(do peeps still use them today) you use that to open pipe instead of using joiner or even open up joiner a smidgen.
Socket former : I had completely forgotten about that option ( age related ) quite neat for surface work (although does it matter under the floor) toolstation do one for £9.00. Plus a 15mm to 1/2 inch copper connector : I will then have everything to hand once I cut the pipe. I know that 1/2 inch was the internal size, that’s around around 12.7mm. The walls were a lot thicker those days and it varied. I guess the reason that some will say it fits into 15mm fittings and some have problems. However! good replies I will now have everything on hand for the job and KIAB thanks again for reminding me I am seriously thinking of getting one of those tools to open up the 1/2 inch pipe to go over the 15mm pipe ( only one joint ) assuming the pipe will not fit directly into a 15mm tee.
But, I have one of these swagging tool, make expanding pipe for a socket so easy, I still keep it, even though it's seldom used nowadays. Now this looks a good tool.
Most of this is overkill for the OPs problem. As suggested, try the fitting and if very tight, a couple of quick circular rubs with emery cloth then wire wool. Check for fit, flux, assemble, solder.
You and your oversimplified solutions to problems.... Give the others a chance to suggest complicated and time consuming and costly alternatives... Rs
Why spend more. https://www.bes.co.uk/old-to-new-copper-metric-to-pre-1970-imperial-15-mm-x-1-2-19480
Exactly..........I love it when the DIYers are advised to invest in test gear, crimping tools and soldering irons...when half of them cant even pee straight...never mind about soldering..... If Op cant solder use a push fit fittings..thus. RS
I’ve both of them. Not used very often thou! Get out of jail card. But I’m also not plumbing full time either