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Isolator Valves on Pushfit Pipe

Discussion in 'Plumbing and Central Heating' started by tododo, 18 Nov 2018.

  1. tododo


    8 Oct 2006
    Thanks Received:
    United Kingdom
    Hi all
    About to start plumbing up kitchen island - we have plastic pipe as the main feeds under the screed

    I have taps and a dishwasher to feed into - just wondering if there is a preference for compression isolators (using the plastic inserts in the pipe) or should just get the JG isolators as it looks a touch quicker

    Also do I need any sort of check valve to stop dirty water coming back into to the main supply (if it can that is)

    Thanks all
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  3. Tozzy


    6 May 2006
    Thanks Received:
    United Kingdom
    Just the thoughts of a diy'er but as you've not had any other responses, I'll tell you as much as I know on the subject ! I can't say though whether to go with plastic as I've never worked with it.

    The majority of flexi tap connectors, isolator valves and supplied tap tails will all reduce the internal pipe diameter considerably. So any 15mm compatible fitting will have an internal measurement of maybe 8-10 mm (I'm guessing here a bit, but reduced definitely)

    If this is enough to make a significant reduction though, I cant answer that

    If your concerned though, why not fit a "full bore" valve as means of isolation. As a side note, I'm having problems with my mains cold water pipes disturbing me at night when someone runs the kitchen tap and I can't help but wonder whether it's because I didn't fit full bore iso valves :(

    An example of full bore:


    If you decide to use, ensure that you use inserts in your plastic pipe (same make inserts as pipe).

    Sounds like you've answered your own question :D Yes, I'd always fit a single check valve before either a washing machine or dish washer. In view of today's byelaws, I would assume it is now required (could be wrong however). You may already know you can get 3/4" washing machine/ dish washer isolators with built in check valve. However, I don't know whether you'd need a straight or elbow but from experience, I could never find an elbow with built in check valve, only straight.
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