I need to connect two pieces of iron pipe (ouside diameter 27mm, 1 and 1/16
with something flexible, about 2 metres apart, to carry hot water.
Lots of PVC piping available, but I can't find anything to mate the iron to the
Any suggestions, please?
Probably a universal coupler.
Your flexible pipe will need to be MDPE as that is what the other end of the
adaptor expects but it may be possible that a universal-unversal version
On Tuesday, September 25, 2012 12:20:37 PM UTC+1, Bob Martin wrote:
Are there screw threads on the ends of the iron pipes?
I'd just use whatever PEX is available, JG Speedfit or similar. How you'd attach
it depends on the above.
Steel pipe isn't good for HW, the oxygen in the water causes corrosion
problems. Galvanized was used. You probably know that.
On Tuesday, September 25, 2012 1:24:42 PM UTC+1, Bob Martin wrote:
Ah, if it's CH and not potable, then iron is used but you have to use
inhibitors to stop corrosion.
Use PEX, JG Speedfit or similar barrier pipe, designed for CH. Don't use MDPE.
Re joints, I'd expect Speedfit do a grip ring fitting, but I'd look further
along the pipes for a screwed joint
I could undo with a two stilsons to use a threaded adaptor.
Is it feasible to remove more of the pipe, by tracing each piece back to
a threaded joint. If you could then unscrew both pipes, you could
replace the whole length with plastic - using threaded joints at each end.
That is 3/4" nominal bore, so you are looking for 3/4" fittings. Iron
and steel pipes are not measured by the OD. Nor are rigid PVC pipes, if
the size is given in inches.
If the iron (or steel unless it is very old) pipe has threads on the
ends, the easiest way would be to look for 3/4" BSP female threaded
adaptors to your choice of flexible pipe. Alternatively, there are
Primofit compression fittings for connecting steel pipes to HDPE.
I phoned 6 local plumbing centres yesterday, each passing me on to the next,
until I got the Universal Transition Fittings at the local Drain Centre.
However, I'm disturbed to be told by another poster that I shouldn't use MDPE
for CH as, although I only needed 2 metres, I had to buy the minimum qty of 25m.
And it isn't anywhere near as flexible as I'd hoped.
It gets more flexible if you run some hot water through it.
The only reason I can see why it might not be a good idea is it may be
permeable to oxygen - ie let a little into the CH water causing corrosion.
On Wednesday, September 26, 2012 8:12:18 AM UTC+1, Bob Martin wrote:
Plumb Center, Drain Center, etc.. They're tossers, just looking to charge you the maximum possible, they don't care that you'll never go back. They don't want you back, they cater for trade accounts and negotiated discounts. If Screwfix don't stock it, try BES.co.uk.
Car radiator hoses are mostly permeable to oxygen, which is partly why you should change most anti-freeze every few years. There's no reason why you couldn't use copper, if you keep the inhibitors up, but it's not a pukka fix.
I've never run hot water through any PE, I suspect it will become too floppy to be useable.
you the maximum possible, they don't care that you'll never go back. They don't
want you back, they cater for trade accounts and negotiated discounts. If
Screwfix don't stock it, try BES.co.uk.
should change most anti-freeze every few years. There's no reason why you
couldn't use copper, if you keep the inhibitors up, but it's not a pukka fix.
I think the problem is not so much floppiness as *creep*, i.e. it will
gradually stretch under the pressure and gravity loading until it fails.
Is it a horizontal run? If so it will survive longer with frequent supports.
It's possible to hire an electric pipe threading tool that exerts no
torque on the existing pipe sytem. (There is an anchor that grips the
If you don't thread it,there is a strong possibility of leaks
depending on the state of the outside of the pipe. (pitting/corrosion
etc) with compression fittings.
However if it's that bad, you need to consider replacing all.of it.
The cowboy option is to get some thick walled plastic pipe with an internal
diameter matching the external diameter of the iron pipe, and then secure it
with jubilee clips.
Some of the large bore clear plastic pipe I have seen is very (vey) thick
walled although I doubt it is approved for CH use.
No plan survives contact with the enemy.
[Not even bunny]
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