I'm sure it's been asked a hundred times before but I can't seem to find a straight answer anywhere. Can I use a normal 15mm hep or speedfit fitting on an old 1/2" imperial copper pipe? I have a bag of these already and am moving a radiator to another wall so want to go from the existing 1/2" flow & return under the floor in plastic to the new position then come up through the floor with 15mm copper tails
I wouldn't risk it, it may seem fine initially but with imperial pipe being slightly smaller there's always the risk it pops off. You can get an imperial coupler - Speedfit NC471
Nope, need adaptor Speedfit -NC471. https://www.ondemandsupplies.co.uk/...dfit-BLUE-Conversion-Connector-%2d-NC471.html
Thanks - didn't know they did those, will pick a couple up. TheMorg I'm sure the imperial pipe is slightly larger not smaller hence thought it may be ok?
Also - obviously being old pipe the copper is dull though not dented or scratched, can I just give it a wipe and pop one of these NC471s on or does it have to be brought up to a shine?
Cheaper to buy copper 15mmm to 1/2" imperial metric end feed fitting. http://www.jtmplumbing.co.uk/pipe-f...+listing+ads&gclid=CM_8rIrZyM4CFaQV0wod9S4JJA
You're right, I'm confusing it with 3/4" which is smaller than 22mm. For the sake of £5 I would still err on the side of caution and use a 1/2" - 15mm, unless it was getting late on a Friday afternoon of course.
Not as straightforward though I assume the push fit can go straight on the dull copper? Can't find anything in the literature that says otherwise
Is there a sure fire way of telling if what I have is imperial or copper? They look so similar. Here's a photo - left is a piece I cut off a new length of 15mm and right is a small offcut I found under the floorboards:
Metric pipe came in around 1972,hardly any difference between 15mm & 1/2", it's 22mm & 3/4" that is only the real problem. 15mm, 1/2" is roughly the same, just a little tight to put fittings on, that why use use imperial to metric adapator, gives some room for the solder to flow.
Thanks for this. My calipers aren't digital so would be too much help so I'll slip a fitting over and see if one is noticeably tighter than the other! Or maybe I should just rule out any doubt and use a 15mm compression fitting on the potentially imperial side to a stub of 15mm and come off that in the plastic?
Looking at this example of a 1/2" pipe would lead me to think my house is metric as the wall of my pipe doesn't look anywhere near that thick... http://harrycooper.com/images/product-large/4030.jpg
The wall thickness in that photo looks deceptive - it looks as tho' it's cut on a bevel for a start. Oli, if you have calipers, then chust set them on the largest tube and then see how much gap there is when tried on the narrower one - according to KIAB's chart above, there should be around 0.8mm difference if one is imperial. That should be pretty obvious - the pipe should rattle betwixt the caliper legs... Yes, you could always go the compression route, but I'd personally rather have soldered under my floorboards. Having said that, a compression joint carried out with a good smear of Fernox Hawk on the olive and threads and not over-tightened should be pretty much 100% reliable. If a half-inch pipe is really 15.875 O/D I'd have thought a Yorkie would struggle to be fitted - it would need a very firm tapping on, and you wouldn't be able to easily pull it orf afterwards?
I have just ripped out the last 3/4" from my house - except a 2.5m drop from loft to hot tank (and that will be done soon). A friend with an old cottage which has a large amount of 3/4" has asked me to save the long lengths and compression fittings for him - just in case.
Thanks. I've popped both in a fitting and can't see any difference - if anything the one I know is 15mm is a slightly tighter fit. Even if the other one was imperial as it's slightly larger I can't see what problem there could be using a 15mm speedfit fitting on it whereas if I were to use the 1/2" to 15mm and it turns out it actually is metric it will be a looser fit and potentially leak
I have just measured some 1/2" and it is actually 15.2 to 15.3 mm quite a bit different from the 15.875 in the table. 0.3mm can be taken up but if a fitting was big enough to take 15.875 pipe then capillary action would not work to allow solder to flow. The same table put 3/4" at 22.335mm - but I have always found it looser that 22mm so it cannot be that size. The tube here measures 21.3mm which as known will fit into a solder joint but will not solder satisfactorily.
Well I'm glad it's not that stupid a question - definitely doesn't seem that straightforward! Would we all agree that whatever the exact measurements, 1/2" copper has a bigger outer diameter than 15mm copper and therefore if I can get a 15mm Speedfit on it then it should be fine? Seems a bit of a risk to use the NC471 on what could actually be 15mm and therefore cause a leak.
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