Poly pipe leak at coupling

Black poly pipe leak at coupling

Here's a first, at least for me.
A customer of mine's poly line developed a crack halfway to his house, shortest distance would be 120 feet.

The mains are running high pressure with the homes having PRV's.

The new black polyethene fits the brass insert couplings fine with no leaks.
However the old black poly pipe that has been under high pressure for maybe 20 years seems larger and doesn't seal.

Has anyone else encountered this before?

I've patched poly before with no problems, but I'm thinking that maybe the old pipe has grown in size over the years.

black poly ?

what kind of pipe are you talking about here???

the crestline black poly they use to bring water into the house with???

or some thing else??


We ahd troubles with some defective black poly that sort of
split down the seam way back years ago...

it was on the incomming line to the house..
about every year we had to go back out and keep cutting it back a few

more inches untill we hit the in -comming wall

then the fellow had to change the whole line to the meter

which he should have done in the first place..
if it is cracking up a seam in the pipe, it will continue

----------------------------------------------------------------------

I have run into the swelled stuff before too and I remember getting
out of trouble by beating a barbed metal fitting into it, then
clamping the hell out of the joint....



of course this restricts the flow a lot
but you do what you gotta do....to get the water back on

I had to pound in the brass insert couplings into the new poly pipe after heating it some, the insert fittings slipped right into the old poly without heat. Two very different size pipes it seems.

If the inserts fit tightly into the old pipe, I'm sure I wouldn't have the leaks.
It's like I need different size inserts on each side.

heat the pipe

TERRY<

this sounds really half assed here,

but I had to resort to this once and it did work well

find an insert that is slightly too large to go into
that pipe , then heat the plastic with a torch...
waveing the torch back and forth being
careful not to set the thing on fire....

once the pipe is hot enough,
it will give enough to let the insert slide in..

I've seen some old 100 and 125 psi rated PE tubing 'grow' albeit very rarely.

I and others here always heat PE tubing for insert fittings, actually doing so is in the installation intructions, but you aren't supposed to use a torch/flame which we all do. Doing so voids the warranty. They want hot water or hot air that will heat the inside and outside evenly.

Gary
Quality Water Associates

Update on repair

Here is the update on the enlarged poly pipe.

We left the couplings and the repair in the ground to set for a while.

After a couple weeks on daily warming and coolings, the pipe finally snugged up to the couplings. When the homeowner pulled and twisted on the fittings, he couldn't make it leak.

A weird but interesting problem for sure. I think you were right about the tubing growing over the years due to the pressure exceeding the rating of the tubing and possibily the water company or customer use etc. has decreased it now.

Or... since the leak occured in that spot, maybe one side of that place can expand/contract and the other side can't and that 'grew' the ID in that spot and that was the cause of the leak and the greater ID. Does that make any sense?

Gary
Quality Water Associates

Suggestion

LEAVEthe trench open for a couple of years ,just in case

ain,t plumbing fun ?

There are different kinds of poly pipe. There are SDR and SIDR types. SIDR stands for standard inside dimension ratio and accepts insert fittings. This pipe is common for well drillers and private home installation work. City’s and rural waters projects that are designed by engineers often use an SDR pipe which is driven by the outside dimension. Insert fittings do not fit into SDR pipe without a lot of heating. We all use inserts, but the manufacturer does not like us to heat it. Also, poly pipe will creep over the years as its molecular structure is the same as PVC. Our local municipal supply house recommends that we use a pack joint fitting on all poly connections. Of course this makes sense to them because they are more expensive. The pack joint is a mechanical coupling that has on outer gasket that is mechanically compressed. However, because poly will give over the years a stainless steel stiffener must be used inside to keep the poly rigid.

To your problem. It is possible that your large pipe is actually a SDR size large then your new pipe.