Author Topic: Dishwasher. Drain through disposal or not. Which is best?  (Read 6739 times)

Offline Rick52768

  • VIP Member
  • Member Since: Nov 2009
  • Posts: 47
Dishwasher. Drain through disposal or not. Which is best?
« on: November 20, 2010, 07:14:31 PM »
Just wanting everybodies opinion on what is the best way to hookup a dishwasher drain so the dishwasher works the best.  Through the disposal? Or straight to the sink drain?  My two cents is that the dishwasher already have grinders in them and if the disposal in full, clogged, etc. . . you will have issues, so straight to the sink drain with a sink mounted airgap is the best. Thanks for your opinions.

Offline AJ

  • Technician
    Administrator
  • Member Since: Jun 2007
  • Posts: 9320
  • Country: us
    • ApplianceJunk.com - Appliance Repair
Re: Dishwasher. Drain through disposal or not. Which is best?
« Reply #1 on: November 20, 2010, 07:19:51 PM »
Most often what I see is if there is already a disposal under the sink then the dishwasher drain is connected to that. I believe this is out of convenance because all you have to do is knock out the drain plug and connect the dishwasher drain hose to the disposal.

I don't really feel there is much of any advantage one way or the other.

If you already have a disposal under the sink I would simple connect the dishwasher drain hose to it and move on.
Hope you find our site helpful.
Follow us on Google+

Offline Tuco

  • Technician
  • Member Since: Nov 2010
  • Posts: 89
Re: Dishwasher. Drain through disposal or not. Which is best?
« Reply #2 on: November 20, 2010, 08:12:35 PM »
I like what AJ said. Why make trouble for yourself?

Drain hose up to the air gap ( on your sink) then down to the deposer. Be sure and knock the drain hole cut out with a long screw driver, then hose and clamp.

If you don't have an air gap, run the drain hose as high as you can( under your sink) then down to the desposer.


Offline Rick52768

  • VIP Member
  • Member Since: Nov 2009
  • Posts: 47
Re: Dishwasher. Drain through disposal or not. Which is best?
« Reply #3 on: November 20, 2010, 09:20:54 PM »
Well, it is broke and I am trying to fix it. My airgap has black crap that likely came from a disposal that somehow backed up.  I always run it to clear any food or water right after running hot water in the sink and something still happened to cause the airgap to look as it does.

PS. Fire was a incredible invention that changed the world, but I am glad that we did not stick with it as it was good enough. How about wet venting. It worked fine for a long time. Not trying to be a pain just questioning the reason why we drain through the disposal and a matter of it is there is not a good reason in my book.

Offline AJ

  • Technician
    Administrator
  • Member Since: Jun 2007
  • Posts: 9320
  • Country: us
    • ApplianceJunk.com - Appliance Repair
Re: Dishwasher. Drain through disposal or not. Which is best?
« Reply #4 on: November 20, 2010, 09:46:23 PM »
What do I know, I'm not a plumber. ;)
Hope you find our site helpful.
Follow us on Google+

Offline Tuco

  • Technician
  • Member Since: Nov 2010
  • Posts: 89
Re: Dishwasher. Drain through disposal or not. Which is best?
« Reply #5 on: November 20, 2010, 10:36:46 PM »
Rick , the black junk in your air gap is probably from the dish washer .

   I'm not a plumber either.

Offline Rick52768

  • VIP Member
  • Member Since: Nov 2009
  • Posts: 47
Re: Dishwasher. Drain through disposal or not. Which is best?
« Reply #6 on: November 20, 2010, 11:10:12 PM »
Does the black stuff mean I have a dishwasher issue or a drain issue?

Neither a plumber or an appliance repair tech, but I did sleep at a holiday inn last night.

Offline theoldstoveguy

  • Technician
  • Member Since: Jan 2008
  • Posts: 1258
  • Country: us
    • Buy me a beer through paypal
Re: Dishwasher. Drain through disposal or not. Which is best?
« Reply #7 on: November 21, 2010, 11:34:15 AM »
I was told the reason to drain the dishwasher into a garbage disposer was, because the old machines (and a lot of new) would let food pass through the pump. This would make it so you would chop up food to prevent blockage in the plumbing lines.

Offline BrntToast

  • VIP Member
  • Member Since: Nov 2007
  • Posts: 388
  • Mayday Appliance Service
    • frigidaire service blog
Re: Dishwasher. Drain through disposal or not. Which is best?
« Reply #8 on: November 21, 2010, 02:02:45 PM »
air behind water to make it flow
remember, older plumbing does not work with newer dishwashers
most older dishwashers had a motor to pump the drain water, this motor was rated in horsepower and could force water down a drain
newer machines use  a satelite drain pump, its so weak its rated in watts now, not horsepower, if the drain is not vented it wont drain

most disposals have a 3/4 inch opening and the drain hose on newer machines will fit this
most under sink drains are 1/2 inch, hose will still fit, but if you read the install directions the manufacturer will say the drain opening should be 5/8 or larger

bigger is better with a drain
personally i dont think the disposal serves any purpose as far as chopping discharge from the dishwasher, nothing that large makes it through a dishwasher anyways, it plugs the machine, or destroys it

the only disadvantage to disposal connection is customers that fill the disposal and dont run it right away, this can block the dishwasher drain, but why are people leaving rotting food in their disposal anyways? its gross but some do it
Mayday Appliance Service
Winnipeg Manitoba Canada


The only stupid question is the one not asked

Offline Rick52768

  • VIP Member
  • Member Since: Nov 2009
  • Posts: 47
Re: Dishwasher. Drain through disposal or not. Which is best?
« Reply #9 on: November 21, 2010, 03:16:43 PM »
Good info BrntToast. Did not know about the lack of power the drain pumps have and the issues with older plumbing due to this. The reason I posed the question is due to my dishwasher issues and the desire to resolve the problems. When looking for parts to directly connect the dishwasher to the sink drain the helpful worker at Lowes was less than helpful and that the correct parts to do this direct connection have no place on the shelf. Funny how a matter of ease becomes the reason things are done, not what could be or is the best to do. I have a number of issues that I am battling when it comes to plumbing. Lack of flow (pressure drop to 40 psi when two hose spigots are on), really hard water (frig water filter clogs in two months, can see the mineral "rock" in the sprayers in the dishwasher).  I have taken the dishwasher completely apart to clear it of any mineral issue and turned the hot water up to 130. Btw can safely use CLR remove the mineral chucks from the plastic dishwasher sprayers?

More responses of why or what would be the best for the dishwasher, not the plumber. Even the responses that are just opinions are good. Thanks and keep them coming.

Offline sparky823

  • VIP Member
  • Member Since: Sep 2007
  • Posts: 132
Re: Dishwasher. Drain through disposal or not. Which is best?
« Reply #10 on: November 22, 2010, 12:58:28 AM »
Try running some Dishwasher Magic through it ever month or so. Should clean all the crud out. Finish also makes a dishwasher cleaner that will work like the DM.

Offline Rick52768

  • VIP Member
  • Member Since: Nov 2009
  • Posts: 47
Re: Dishwasher. Drain through disposal or not. Which is best?
« Reply #11 on: November 22, 2010, 07:52:24 AM »
I tried that before, but I will give it a shot again as some of my problems have been "solved". Thanks

 

Kenmore Dishwasher - Doesn't always drain.

Started by yeltu1188

Replies: 1
Views: 3998
Last post September 15, 2007, 10:36:53 AM
by Pegi
Maytag Dishwasher will not drain

Started by fredc

Replies: 4
Views: 2193
Last post May 08, 2008, 07:04:18 AM
by fredc
Frigidaire Dishwasher Won't Drain

Started by TechnicianBrian

Replies: 0
Views: 12922
Last post August 04, 2008, 07:23:26 AM
by TechnicianBrian
dishwasher no drain durning normal , but works on normal ?

Started by JPG

Replies: 5
Views: 2839
Last post August 12, 2008, 05:49:23 PM
by Repair-man
Whirlpool dishwasher won't drain

Started by Henrietta

Replies: 8
Views: 14281
Last post June 04, 2010, 09:21:33 PM
by luvmy8kids2004
Dishwasher won't drain code OE

Started by Cujo

Replies: 2
Views: 6811
Last post October 23, 2008, 06:36:37 PM
by Cujo