Dishwasher supply line- simplify by using a washing machine supply?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by ben in il, Nov 27, 2017.

  1. ben in il

    ben in il New Member

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    Mar 27, 2012
    Location:
    Illinois
    We're replacing an older Miele dishwasher that used a 3/4" shut off for the supply line. The incoming Bosch unit calls for using a 3/4" 90 degree adapter, connecting to a supply line with 3/8" connectors at each end, which would require yet another adapter for the 3/8" line to 3/4" shutoff.

    Any reason I can't use a similar (1,500 psi rated) supply line that already has the 3/4" fitting at both ends and the 90 degree coupler built in? It seems to make sense to me as it eliminates two adapters (and two points of failure), but I sent a note to the Bosch support line which gave me the expected "we can only recommend what is in the manual" semi-automated response. Figuring that Bosch makes dishwashers and washing machines, I thought they'd give it an easy 'yes'.

    Thanks for any insights!
     
  2. cacher_chick

    cacher_chick Test, Don't Guess!

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    It would make no difference. The 90 adapter comes with all of the dishwashers I have seen for the past few years.
    Unless the existing shut off is a "like-new" 1/4 turn valve, I would just replace the shut off with a new one of the correct size and move on.
    The old installs here were mostly done with soft copper tubing, and we replace them with stainless steel braided hose when the dishwasher is replaced.
     
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  4. ben in il

    ben in il New Member

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    Thanks, cacher. Surprisingly, the 90 adapter for the Bosch is on the "things you need to provide" list, so the washing machine hose saves me a few dollars there too.
    The Miele we took out had a proprietary 'waterproof' dual solenoid encapsulated supply line that is a feat of engineering, but also pretty spendy when it fails. That line required a 3/4" connection, and over the years I replaced the standard shutoff with a nice commercial 1/4 turn lever that is very easy to use (and soldered on the copper supply piping).
    Locally, we've got easy access to the washing machine supplies, which seemed the simple solution. And I like simple (without adapters) when possible.
     
  5. hj

    hj Master Plumber

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    Is the 3/4" elbow supply line a hose thread or a pipe thread. They are NOT the same.
     
  6. fullysprinklered

    fullysprinklered In the Trades

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    I'm having trouble picturing exactly what Ben is talking about. Some things are regional and what they do in Illinois may be different down here in Dogpatch, Ga. I've always used the standard 3/8 "ips x 3/8 compression el to connect the supply to the d/w solenoid valve. Now I'm seeing more hose X 3/8 els. Never have I encountered anything in 3/4 size feeding a dishwasher.
     
  7. ben in il

    ben in il New Member

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    HJ and fully- the threads on the Miele hose (female) and the quarter turn stop (male) are hose threads, just like on the standard washing machine braided supply lines.

    Fully- the 3/8 x 3/8 is very standard on most dishwashers, which is likely why the Bosch manual calls to use that with the 90 adapter (3/4 x 3/8). The Miele is the first dishwasher we'd had with the 3/4 hose end. In fact, in an older installation, the installer had an adapter to step up from the standard 3/8 shut off to the 3/4 hose size.

    Here's a picture of the highly engineered proprietary hose (from the departing machine)... MieleIMG_3518.JPG
     
  8. fullysprinklered

    fullysprinklered In the Trades

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    What's next, a square tire?
     
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  9. hj

    hj Master Plumber

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    Many DW and ice makers are going to a hose thread inlet for some reason. Probably so they can use a plastic male thread instead of fabricating a brass 3/8" female inlet.
     
  10. fullysprinklered

    fullysprinklered In the Trades

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    They seem to be easier to install.
     
  11. WorthFlorida

    WorthFlorida The wife is still training me.

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    Location:
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    For dishwasher for at least the last ten years, maybe longer, the water line connection has been changed to a 3/4" garden hose style. The old way was a 1/2" x 3/8" NPT brass fitting. This kit from Home Depot is for both types. In 2012 I bought a new Bosch DW and the 3/4" hose style was the connection. The only reason I can think of is it would allow one part to be used world wide. Each country would have it's own adapter if needed.

    I do not know if the garden hose (or washing machine) 3/4" is standard world wide. (https://www.amazon.com/Garden-European-Thread-Butterfly-Handle/dp/B00J44OIJ). This spigot list 3/4" but it names the type of thread that I'm not familiar with.

    https://www.homedepot.com/p/Everbilt-Stainless-Steel-Dishwasher-Installation-Kit-69005HD/301979920

    Screen Shot 2020-09-23 at 10.16.31 AM.jpg
     
  12. Jeff H Young

    Jeff H Young In the Trades

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    Im not up to date with all the fancy stuff but whatever makes the connection solid, quick, Ive seen the hosex3/8 adapter it gets tossed If I remember correctly .
    That big hose the op showed was on my brothers Miele D/w as well. he replaced it once with the spendy proprietory crap. I converted it to a standard GE solenoid for about a 10th the price and more reliable Ive never had my solenoid go bad 15 or 16 years we replaced the D/W a whirlpool that had never failed .
    Normaly I dont repair an appliance no matter how easy, I just dont attempt unless its my home.
     
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