Central heating pipes expanding longitudanally

[gm3suz]

I have rather a long house, about 90 feet and I'm having problems with the amount of expansion of the copper pipes in the central heating system when they get hot. The expansion has caused a couple of leaks, because as the pipes expanded they were stressing some of the joints. Is there some sort of device or pipe fitting that I can insert evey 30 feet or so that will allow for this expansion ?

Thanks for any info, Dan

 

[ChrisR]

Sure - a bend or three. You must have seen pics of oil pipelines with loops in.

 

[PEDANTICVINDICTIVEMAN]

You can either use propietry expansion couplings or use plastic pipe.

 

[gm3suz]

It's a bit impractical to replace my 200 feet plus of copper tubing with plastic pipes but the proprietry expansion couplings sound interesting, I am using 3/4 inch diameter copper pipes, where can I find some proprietry expansion couplings ?

Thanks....

 

[CH4]

The telescopic copper connectors HERE may meet your requirements, but I've never tried them myself.

 

[gm3suz]

Thanks CH4, will try a couple of those and see how I get on. Best Regards and have a very Happy New Year.

 

[ChrisR]

I wouldn't be happy to use those, they'd leak after a few cycles I would expect. If you use 4 elbows and a long as poss sideways diversion sideways and back, those pipes would bend quite easily. It could all be at one endwhere you might be able to use 15mm which of course bends more easily.
I don't offhand know where you'd get a propietary expansion device suitable for CH. I can get them from pro suppliers, but not DIY. Tap flexies will not do!

 

[bripl]

bend an expansion loop in the main long runs shaped like a omega sign the term you need is linear expansion,saves on fittings 4 couplings and a couple of offcuts of pipe remember to anchor the pipes so the loop takes the expansion hope this may be of help

 

[gm3suz]

Thanks Bripl and Chris, I will try and fit that omega shaped linear expansion thingummy as soon as it gets warmer. I have plans to fit a new boiler and a couple of new radiators this summer and I can do that at the same time. I will fit the special expansion bend in an airing cupboard that the central heating pipes go through and of course anchor it securely, Best Regards.

 

[ChrisR]

Know what you both mean by an omega - as used on oil pipe lines - but they use fittings designed for the purpose.
a) it takes quite a lot of space in 22mm - more than may be convenient between joists, which is the main objection and
b) I've seen them split in copper. Reason I assume is because the copper work hardens a lot when you bend it. Repeated further deformation can therefore be in the plastic region which eventually causes high-strain fatigue failure. It would probably help enough if you softened the copper by heating it on all the bends, but I don't know.

 

[bripl]

bends like the omega are commonplace in heating and if formed correctly do not split/tear you can do them easily with copper pipe bendersnowadays they have been replaced by expansion bellows or the expanding couplings which do tend to leak after a while.omega bends will do the job in a cupboard/under the floor no problem the amount of expansion roq for 90ft approx 25mm so size is not that important one on the flow one on the return properly anchored stops copper popping/flooding and they are normally used in black iron on hthws using steam hope this helps

 

[ChrisR]

25mm only allows for about 50 degrees hot - cold which is a bit low, and I've not seen any indication of im"proper" bending on the split ones. One was a hotel - expensive! Yorkshire elbows split quite often too.