plastic pipe blows out of compression fitting

[bill flynn]

hi all I am looking for a bit of advice about using plastic pipe with compression fittings. I recently had a plumber fit a grohe shower plate for exposed shower valves and he used speed fit plastic pipe. all has been fine for the last four or five months then all of a sudden the plastic pipe has popped out of the compression fitting flooding the house causing 10k worth of damage. how can this pipe have withstood mains pressure for the last four months then pop out. it is worth mentioning I have known this plumber for ten years and he is a competent tradesman . I know he uses the plastic inserts with the rubber washers or rings round them, please excuse the terminology if it is wrong, and the compression nut was fully tightened I checked it for myself. this was on the cold side of the shower supply. as if this isn't bad enough after repairing all the flood damage it has happened again now on the hot side. luckily someone was at home this time to turn off the supply limiting the damage. my question to everyone is, is it acceptable to use plastic pipe with compression fittings or should you only use copper. any advise would be greatly appreciated. many thanks Bill

 

[Ray Stafford]

I know he uses the plastic inserts with the rubber washers or rings round them

from the John Guest website - my emphasis

Two types of pipe inserts are available; Standard and Superseal. The Superseal insert contains two 'o' rings to provide even greater sealing security. Both types of inserts are suitable for JG Speedfit hot and cold water and heating systems. An insert is always necessary when using Speedfit pipe. However, should an installation be required using a compression fitting, a TSM standard insert must be used.

 

[Mike Jackson]

Took the words out of my mouth Ray.

 

[chris watkins]

I would guess that the extra length of the front end of the 2 'O' insert means the olive is to close to the end of the pipe, this combined any surge pressures within the mains water supply & the fact that the pipe is elastomeric (it stretches) has caused the pipe to work free over time.

It is always worth reading the Manufacturers Instructions before beginning work, something the younger generation seem to have great difficulty in doing IMHO.

 

[gassafe]

Brass I bet...

 

[Gray0689]

What material was the olive?

Copper or brass?

Copper olives much better imho for compression fittings like this
Brass to hard to compress

 

[bill flynn]

not sure what the grohe plate comes with copper or brass but will check with my suppliers. Sounds like the problems lies with the inserts used according to replies received. thanks anyway

 

[Rickster123]

Hope he was insured??

 

[Ermintrude]

Probably didn't push it into the compression fitting enough!

 

[Phil]

I know of a house all done in unclipped Speedfit by a DIY'er and as he didn't trust the push fit fittings he's used bags and bags of Screwfix compression fittings (Flowflex).

Superseal inserts and hard brass olives.

I don't this this guy likes his ceilings.....

 

[Chalked]

Some of the Grohe brass olives are very hard, as are quite a lot of German made fittings.

 

[gassafe]

Another reason not to use plastic lol

 

[Kyle87]

I sometimes think to myself, I should start using speedfit as I'm going to get left behind by plumbers who are in and out quicker because they simply snip and click their pipework

Threads like this confirm my belief in copper.


By the way I'm sure when fitted correctly that plastic can be ok. But for my I'm going to carry on staying away!!

 

[lame plumber]

why do they always fit more elbows than required?

 

[dancinplumba]

Lot of copper elbs there 🙂

 

[Ermintrude]

why do they always fit more elbows than required?

To balance out flow. They have done very detailed fluid dynamic analysis and have calculated the exact head losses , to ensure perfect symmetry in supply dynamics .

 

[lubba1974]

Hi all, I have been plumbing for 9 years, not that long compared to a lot of you .. When I was at collage I was taught that with jg speed fit the 2 different types of inserts are for different fittings, the insert with the 2 rubber O rings is for jg push fit fittings only and the insert with NO O rings is for compression fittings.
I have used this method and never had a problem. I was also informed in my local merchants that this was correct as well .Hope this helps guys.

 

[gassafe]

Stick with polyplumb... None of this 2 inserts business...

 

[Phil]

Stick with polyplumb... None of this 2 inserts business...

No, just one Mickey Mouse insert to suit all.......I've seen more Polyplumb blow off's that any other brand.