plastic push fit on mains water

Discussion in 'Plumbers' Talk' started by SteveMJ, Apr 3, 2012.

  1. SteveMJ

    SteveMJ Member

    I suspect his has been asked before, so apologies in advance for re-asking.

    I have to alter some kitchen plumbing (yes, I am trying to engage a plumber), but need to sort some pipes to allow other progress and not hinder other trades.

    I have an iron water pipe that rises from a kitchen floor.  I need to relocate the cold water pipes to allow fitting of units etc and expect the 50 year old iron pipes may be rusting internally.

    Can I use push fit plastic pipe and will it be robust enough to withstand the continual mains water pressure?  I had been thinking of copper and use either solder or compression joints, but feel I may be ignoring the benfits of the lower cost and ease of installation of alternatives.  Would it be advisable to use copper for the transition from iron pipe to stop cock, ie iron - copper - stopcock - plastic

    Following on from this I also need to supply hot water to the kitchen appliances and sink; can I use plastic push fit for this too?  Its lower pressure but hot of course.

    Thank you for the advice.

  2. tom.plum

    tom.plum Screwfix Select

    you can go from iron to plastic with no problems at all, as long as you fit them to the manfactures instuctions and use inserts, the hot will be ok too,  the only restriction on hot, is that you must not connect direct to a boiler, there must be at least 1.5 metrs of copper first, but I seen it connected to the boiler on many occastion with no problems,
  3. SteveMJ

    SteveMJ Member

    Thank you Tom,  (again - you gave me good advice a while back when I had a problem with hard-to-get-to copper pipe joint, that turned out to be 3/4")

    So, if I understand correctly the plastic is entirely suitable and cost effective too.  Is there one manufacturer that you would reccomend, especially for someone of limited experience - me (and now my son who is renovating his first property/home).

    Guess what we are doing over the Easter break :)

  4. G Brown

    G Brown New Member

    Modern push fit systems are designed for hot, cold, mains, low pressure etc.
  5. SteveMJ

    SteveMJ Member

    Thank you Tom and G Brown.

    Is there one manufacturer that you would reccomend?

  6. clive holland

    clive holland New Member

    I used to use speedfit, though I now use Hep2o fittings. I find them more reliable and can trust them to work under floors etc . A bit more pricey but peace of mind. Like with any other fitting, just make sure the pipe is home and the nuts are tight before testing.Every now and again there's one which misbehaves,Good luck with that one then..........cheers guys

    HOTDOG Guest

    Dont want to worry you but they tend not to leak, but they can blow off when water pressure changes.The higher the pressure the better they seal and you are far more likely to have problems where there are major fluctuations in pressure particularly on the low side.
  8. Crowsfoot

    Crowsfoot Well-Known Member

    That iron pipe is a little worrying.
    Whilest you have everything out of the way it would be a good idea to dig outside and find that iron pipe and renew the section in plastic that feeds into the house.

    I accept this is a lot of work - but you don't want to get your lovely new kitchen installed only for the iron pipe to burst underneath the floor (they often go on the elbow underneath the floor leading upwards to the kitchen)!

    Horrible stuff this iron pipe!
  9. tom.plum

    tom.plum Screwfix Select

    horrible indeed, there's so much muck in there, if you saw it, you'd have it changed, I have a vid some where, I'll look for it and post later,
  10. tom.plum

    tom.plum Screwfix Select

    here Steve, you might find this informative, if admin zapp it before you see it,
    google, 'thetomplum'. It will be the latest vid so should be right on top,

    Message was edited by: Screwfix Moderator
  11. SteveMJ

    SteveMJ Member

    that is brilliant Tom,

    Will have to look the video evening as so much is blocked here at work (my day job).

    I propose to do a short section in copper, up to the stop cock, then use speedfit for cold and hot.  This is fundementally as Screwfix sell Speedfit and there is an sales-outlet about 1 mile from the house.

    IIRC there are different materials for the pipe stock, is that significant for my application?

    Many thanks, Steve
  12. SteveMJ

    SteveMJ Member

    Hi Tom,

    I had a quick look at your video this morning - thanks for that :)  I am presuming you mean the one entitled "toms top tips underground pipes"

    It would be a huge job to remove the iron pipe - digging up the alley way between the house and the neighbours and the communal path.  The stop cock at the boundary was about 0.95 m down (had to buy an extra long tool to turn it off!).  Ican see PE-X and conduit.  I am assuming at the moment that PE-X is what should be used?

    As the JG Speedfit pipe is about 1/3 of the cost of copper I propose to go this way; unless advise to the contrary.

    Thank you for your help - sorry if you feel I'm asking too simple questions.  Its always easy when you know the answers :)


    I was expecting to use something like Conex Female Iron Coupler 22x1" Product Code: 44899 to conenct to the iron pipe.  There is a stop cock already connected (but it will be right on the joint of two kitchen cabinets!).

    In your video your referred to 'Alkathene pip' - if I heard correctly.  I can't see this in the Screwfix catalogue/website
  13. tom.plum

    tom.plum Screwfix Select

    Hi steve, Iknow what you mean about it being a big job, anyrode, If I'm reading this right, you are going to screw the stoptap off the pipe and use that coupling to connect to the iron pipe and change to plastic and then fit a new tap and carry on in plastic, all well and good,
    things I'm not sure about,
    1. the usual size of iron pipe coming into a house is 1/2, so that coupling won't fit
    2. the stoptap will not readily unscrew off the pipe, it will snap or the pipe will break after a long and hard battle with stilsons and heat,

    a photo would be good here so i can see what your proposing to do.
  14. SteveMJ

    SteveMJ Member

    Hi again Tom,

    Not replied as had to support plasterer on Friday afternoon and most of yesterday.  This included taking out the existing iron pipes from the kitchen through the bathroom and up to the hot water tank.  [Those iron pipes must have been a mission to install - probably not too bad on a new build where there were installed before the flooring and internal walls, they are certainly difficult to remove!].

    Well, as a result of this work I've discovered that the incoming mains water is in a PLASTIC pipe; Yes, I got that wrong.  The plastic mains inlet pipe did have a brass adapter, a brass stop cock and then iron pipe for distribution around the house.  It was all painted white some time ago, so to me looked all the same.  With the pipe and stop cock removed there was no support for the plastic pipe and was clearly not rigid.

    The plastic pipe's internal diameter is, I guess, about 1/2" (12 mm).  I can measure that later today.  I have left on the adapter and have a stop cock on for now that allowed the plasterer to get water.  I propose to leave the adapter on and attach the Speedfit, but am not sure what size; 22 mm or 15 mm?  I will ask that as a seperate question as this one has been kindly answered by you and also G Brown and Clive Holland.

    Thank you again for your help.


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