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View Full Version : Can I drain a dishwasher in the same way as a clothes washer?


ariannsgma
Jun 1, 2013, 11:00 PM
When installing a new dishwasher today, I found that tub is much deeper than in the old dishwasher and the pvc drain pipe is too long after the elbow. I would like to know if I can drain a dishwasher in the same way as a clothes washer? If I can cut the pvc pipe back to the elbow and run the drain down the pipe, there is enough room to put the dishwasher in correctly.
If I have to, I can cut the dry wall down under the elbow and cut 2-3" out of the bottom of the pvc pipe in the false ceiling to lower the drain pipe.
Thanks for your time and opinion.

massplumber2008
Jun 2, 2013, 06:29 AM
Hi Ariannsgma

Most dishwashers connect under the kitchen sink... can connect to the disposal or to a branch drain tailpiece.

If you pipe the DW drain this way the dishwasher discharge hose must loop up high and connect to an AIR GAP (some states) or just loop up high to the under side of the countertop and then turn down to connect into the drain (as above). In this way, water from the sink cannot drain into the dishwasher.

Let me know more information...

Mark

speedball1
Jun 2, 2013, 07:11 AM
Air gaps come in two flavors. High loop and counter top.(see images).

ariannsgma
Jun 2, 2013, 07:20 AM
Hi Mark,

My mistake, sorry. I should have mentioned that the dishwasher is located on an interior wall about 5-6 feet away from the sink; the sink is located on an island in the middle of the room.
There is no garbage disposal on the sink; this home (built in '77) is on its own septic system, not city hookup. I would need run drain line under the subfloor, across the room, and up though the subfloor/cupboard and would have to re-plumb everything under the sink, as there isn't a branch drain tailpiece, to tie the dishwasher drain into it.
That's why I was wondering if it's safe to drain a dishwasher in the same way as a clothes washer, because it would require much less modification to... well, everything :)
Thanks for your help!

speedball1
Jun 2, 2013, 07:56 AM
As long as you install a high loop next to the dishwasher simply install a branch tail piece (see image) under the sink and drain t into that. Good luck, Tom

massplumber2008
Jun 2, 2013, 08:22 AM
If a drain isn't handy next to the dishwasher then most people just install the branch tailpiece Tom posted a picture of and run the DW hose over to the sink.

If you don't want to do that then I see no reason you can't connect in to the PTRAP as long as you have a standpipe coming out of it like a washing machine drain and you make an indirect connection, i.e. connect by sticking hose into drain say 12-18" max. In this way, if the drain lines become clogged (sink and DW), waste water cannot back into the DW and will overflow the pipe showing you that you have a problem.

Mark

ariannsgma
Jun 2, 2013, 10:20 AM
Thank you both for your suggestions. I'll try to cut the elbow off the standpipe and install a branch tail piece. That looks like a better solution than just running the drain line down the pipe. Thank you again.

speedball1
Jun 2, 2013, 12:19 PM
Install the branch tailpiece on what stand pipe? Please explain. What I wanted you to do is install a high loop next to the DW and run over to the sink where you would replace 6tyhe regular tail piece with the branch tailpiece using a hose clamp. What was your plan? Back to you, Tom

massplumber2008
Jun 2, 2013, 04:23 PM
Yup! Either connect under the sink cabinet and install the branch tail piece OR just stick the DW discharge hose in the drain as discussed... no need for branch tailpiece if just sticking hose in drain. Here, this will NOT be a better job, just unnecessary. You decide!

Mark

ariannsgma
Jun 3, 2013, 06:06 AM
Hi Tom and Mark,

There is a stand pipe with an elbow at the top that comes through the wall at the back of the dishwasher. It's got assorted connectors to get from pvc to pipe thread and a huge 2" to 3/4" bell coupler with a 2" nipple that takes up too much room.
Since the sink is NOT close to the dishwasher, I would have to run approx. 15' of drain line to get to the sink drain by the time I fish the drain hose down though the wall/subfloor, run it across the room, and back up though the subfloor/cupboard, plus the loop.

I think I found a connector that will cover the stand pipe and hold the drain hose in place called the Fernco Hose Grip Clothes Washer Connector (http://www.fernco.com/plumbing/residential-plumbing/hose-grip-clothes-washer-connector). Doesn't look like the company sells to the public, but thought I would call them. I won't have to cut a big hole in the wall to install connectors and the branch tailpiece. If they won't sell the part to me, I can use a pipe clamp to tie the hose in place.

Thank you both for your help. Have a great day.

speedball1
Jun 3, 2013, 07:07 AM
Here are some hose connections you can use tom secure the hose tom the standpipe. Good luck, n Tom