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Discuss Dishwasher Waste Pipe 18mm to 22mm Help in the Fittings & Pipes area at

  1. Acorn

    Acorn New Member

    Hi All,

    I am a complete NOOB when it comes to plumbing so please bear with me and use baby steps lol.

    I'm trying to plumb in a dishwasher but I am having a problem with the waste hose.

    The hose is pre-fitted to the dishwasher so I can't remove it.

    The hole at the end of the waste hose is 18mm but the copper pipe I need to attach it to is 22mm.

    Is there any kind of adapter that I can use to connect the 18mm end of the waste hose into the 22mm end of the copper pipe.

    Unfortunately I can't change the fittings or the waste hose.

    I have attached a photo of what I am working with, its all original fittings that are there I have not changed anything. Waste Pipe
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Is it the rubber type on the end of the hose ?
  3. Acorn

    Acorn New Member

    Yes it is
  4. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    It's going to be fun but it should fit over

    You could try warming the rubber up in some boiling water for a couple of seconds

    Watch you don't cut your self on the copper pipe when your trying to push it on
  5. Acorn

    Acorn New Member

    Ok cool I will try again. I was just worried about pushing too hard in case the pipe split.

    It's strange as the last dishwasher I had the pipe slipped over the top of the copper pipe with no problem at all as it was a 22mm opening.
  6. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Your best option is to get a proper washing machine upstand installed with a trap
  7. Acorn

    Acorn New Member

    How would I fit that to whats all ready there?
  8. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    You couldn't the waste pipe would need to be altered easy enough to do for a pro
  9. daWilko

    daWilko Member

    Hi Acorn - it might be blind leading the blind (not a plumber and I hate those fittings) but this may have parts you need?
    Washing Machine Drain-Out Kit
    • Like Like x 1
  10. Ric2013

    Ric2013 Plumber

    Looking at the link daWilko has posted, perhaps all you need to do is slacken the lowest Jubilee clip and remove the bit of copper. Might have a nozzle like in the picture?
    • Like Like x 1
    • Agree Agree x 1
  11. sammathias

    sammathias GSR

    That 18mm pipe will strech over the 22mm pipe no bother. Use some man power.
  12. Harvest Fields

    Harvest Fields Trusted Plumber GSR Top Contributor!!

    I would be more concerned with the size of the hole they have drilled under the clamp gr?? And if it will take the waste water away quick enough. Especially if they have fitted it like that in the first place:D:p:p
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