Dishwasher Drain

Discussion in 'Plumbing Forum' started by cibula11, Apr 21, 2008.

  1. Apr 21, 2008 #1

    cibula11

    cibula11

    cibula11

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    We are remodeling our kitchen and are replacing the DW. The current dishwasher drains into a pvc drainpipe. Is there a reason why this was done instead of connecting it to the disposal?
    When we replace the DW can we connect the drain to the disposal and if we do what should we do with the drain? (cap it??)
     
  2. Apr 21, 2008 #2

    hondadrv24

    hondadrv24

    hondadrv24

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    Don't see any reason why you couldn't cap that old pipe and run the dishwasher to the disposal.
     
  3. Apr 21, 2008 #3

    glennjanie

    glennjanie

    glennjanie

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    Hey Cibula:
    I strongly recommend an air gap on the countertop for the Dishwasher drain. It will prevent back siphonage and a lot of sickness.
    Glenn
     
  4. Apr 21, 2008 #4

    cibula11

    cibula11

    cibula11

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    Will running the DW waste line to the top of the sink cabinet and attaching it at the top be sufficient?
     
  5. Apr 21, 2008 #5

    glennjanie

    glennjanie

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    Hey Cibula:
    The bottom of the disposal is above the bottom of the dishwasher, creating a perfect setup for siphoning. Without an air gap the 'loop' has to be over 31' high to prevent backsiphonage.
    Glenn
     
  6. Apr 22, 2008 #6

    cibula11

    cibula11

    cibula11

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    So other than looping, what is the method to install an air gap?
     
  7. Apr 22, 2008 #7

    kok328

    kok328

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    I don't believe an air gap will be necessary as the DW has a check valve on the drain discharge. Just loop the discharge hose so that it creates a P-trap effect under the sink and you should be just fine.
     
  8. Apr 22, 2008 #8

    glennjanie

    glennjanie

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    Hey Cibula:
    KOK may be correct, just check the owner's manual and make sure the check valve is there.
    If there is not a check valve mentioned in the book you will need to go to the HD or L or a plumbing supplier and ask for a dishwasher air gap. It will be an aparatus about a foot long with two different size places to connect to the bottom and will have a chrome hood on top. If your sink has a hole cover on it you can remove it and mount the air gap. If there is no hole you will need a 1 1/2" hole to mount it. The small part connects to the dishwasher drain and the larger one to the disposall. It will not interfere with the draining but when the pump shuts off the disposall side drains down and can't siphon back into the dishwasher. I sure don't want the contents of my disposall running in my dishwasher.
    Glenn
     

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