JG Speedfit - is it rubbish or am I?

11 Mar 2011
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United Kingdom
Tried to do first fix plumbing for a new kitchen today, got all the pipes under floor ok and in position. I bought 15mm JG Speedfit PEX Barrier Pipe and used the standard white JG Speedfit fittings with Speedfit Superseal Pipe Inserts throughout. There was some old grey 15mm piping I was branching off in some of the joints.

Thought I'd got it all in ok but when I put the mains back on the two main equal Ts (one for the mains cold and one for the hot) were leaking, and leaking quite heavily. They seemed to be leaking out of the middle join that had new pipe on it. Bit disappointed obviously and wondering whether to try again or bin it and go for a different system. Which of these is right:

- JG Speedfit is a bad system and you can never rely on it. If so, which plastic system is better for 15mm mains hot and cold water?

- JG Speedfit is an ok system but you should only use it where the pipes are all sitting easily and you have good access. I was trying to fit the Ts in a fairly tight floor void, and two of the three pipes were being pulled away at an angle so did not go into the Ts readily.

- JG Speedfit is a quality system that should be able to cope with joins even in tight spots where the pipes are coming in at slightly odd angles. I'm just a bad workman trying to blame my materials.

Couple of other questions:

How standard is the 15mm pipe? Is it ok to use JG Speedfit fittings on the existing grey pipe? Getting the inserts into the old grey pipe was a lot harder than getting it into the new white JG pipe.

I could probably swap the Ts for a 'Y' shaped joint a bit further back and make all the curves shallower and further from the join. But I can't find any 'Y' shaped splitters. Is it ok to use an equal T then two stem elbows? Would that do the same job?

I've just capped it off for now and retreated but I need to get it sorted in the next few days so I'd be really grateful for any advice.

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Welcome to the woderful world of plumbing in plastics.
It's not knew plastic pipe has been around since the 60s each manufacturer making their own brand different each other nothing ever was standardised!
There's miles and miles of the stuff all obsolite and you can't get the correct fittings for.
Plastic firm comes on the market and produces it's own exclusive pipe for say ten years then the firm goes to the wall and the plastic that the firm produced becomes obsolite.
This IS the problem with plastic!
Plastic ok in the right places. If you want to see a load of plastic pipes and their bulgy connections underneath a sink, it's up to you. Not a professional look to it, and unless fitted correctly, problems will occur.

Plastic pipes are ok under floors and out of view, and quick to fit, but not only look 'diy' in view, but also cause a headache for electrical earthing of your home, which is there to protect you. It never pays to look for the quick solution sometimes. Get it right first time and save having problems later on. :D
I believe that if your taps have more than a metre of plastic pipe connected they don't need earthing.
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Plumbed whole house in JG and not a single leak.
  • did you use a proper pipe cutter
    did you only cut on the line
    did you insert until next line reached union
Speedfit is fine - if: you cut squarely (secateurs are just as good as the proper cutters btw!), if the pipes are square to the fitting and can't flex, and if you push them ALL the way in.

If they freeze, speedfits push the whole joint apart so you have big leaks after, but that does mean for a simple repair.

Now - for you. That grey pipe is probably someone else's, and the sizes are sometimes different. There's no real way to judge this before you start, you just sometimes get a pipe that won't seal no matter what. Sometimes it can be damaged - scored, but as yours is leaking a lot I'm better it's a tiny bit smaller. If you have a micrometer or decent guage, check.

The only way to way to overcome this this I know of is to use standard brass compression fittings with olives. They adjust to a wider variety of sizes.

Use the pipe insert, then treat it as copper. It won't need tightening as much as copper, but the olive deforms the same and cuts into the edge of the plastic enough to soak up the difference. I've done this with probably around a hundred joints and they've all been good, but undertighten first and then tighten with the water on. I've never done it, but I imagine you could overtighten enough for the olive to cut through enough of the pipe to make it a weak point for any movement later.
Plastic is turd that's why. If they leak at first it may leak later in life. Ten year guarantee? Try and get a pay out for this junk plastic and it will be your installation that made a fitting of 3years solid pop off. DIY or emergency use only I say. But that's my opinion.
If you mix fittings, or stress the joints you will have dramas. Also be very careful not to scratch the pipe exterior - it causes leaks and invalidates the warranty.

There is nothing wrong with plastic pipework in the main, it is usually installer error. I'm afraid from your posting it does sound like the latter.

Have another go!
Just had another go with Polyplumb (like the Hep2O system) and it went much better, no leaks at all yet. Is it true with plastic that, if you're going to get any leaks then they're likely to be straight away?

Thanks for all the advice anyway. I find the Polyplumb system a lot more reassuring. When I was dismantling my Speedfit efforts I was a bit worried that I could pull them apart just with my hands, not even pulling that hard. That's supposed to hold back mains pressure for decades?
Mice think its terrific.

There cannot be many plumbers/heating installers reading this who do not have a case of fittings and the odd length of Hep2o/JG pipe somewhere on their van, probably 'just in case'.

Coppers proper.

I am surprised you've had a leak with speed fit, usually if the O-ring is undamaged and the pipe is all the way home it seals well.

My preference is Hep2O - I think the design is better and a similar type of design has been used on the continent since the 1980's

Copper has its place but I think plastic is the way forward.
Speedfit serves a purpose and should be leak-free if the pipes are new (and Speedfit) and unmarked and connections good. Copper can leak from soldered joints, so those claiming it's the only way forward are wrong. BUT it's neater if visible. This hasn't helped, I'm guessing...

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