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When draining water out of the sink, it backflows into the dishwasher. Doesn't the dishwasher have a backflow preventer valve where the drain tube connects to it?

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Actually no they do not have a back flow preventer, make sure the dishwasher drain connection is installed on top of the "P" trap, if it is then you are having drain problems , remove and clean the "P" trap if it not clodded then you need your pipes cleaned out if it is backing up in dishwasher.. Do it sooner than later or may become totally stopped up..

Posted on Feb 01, 2010

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Can backflow mounted to sink be moved under sink?

Hi Del:
I'm not sure what you mean by "backflow".
How is this related to your dishwasher?
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A hand sprayer is typically integrated with the sink faucet.
Reply as a COMMENT to this post to discuss.

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I want to install an RO unit. For the RO faucet connection I would like to use the air gap connection on the sink that connects to my GLD5960 SS dishwasher. Can I get rid of the air gap connection from...

The airgap prevents the water from the sink backflowing into the dishwasher. You could espically if your dishwasher hasa corragated plastic drain hose attach it under the sink so at one point the hose is higher that the nozzle of the disposer it connects to so the hose is still higher that the level of the nozzle and water wont backfill into the dishwasher.


Aug 09, 2011 | GE Dishwashers

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Questions about snaking the drain line for a Bosch SHU5305. Should I be able to snake all the way from the sink connection into the dishwasher or is there some type of backflow prevention or something...

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1 Answer

Some water from when the 20 yr old garbage disposal is used ends up at bottom of our Meile dishwasher. problem with the dishwasher backflow preventer ? or with disposal itself?

Your drain hose should be secured up inside the cabinet at a level higher than the base of the sink to prevent water from going from the disposer back into the dishwasher. There is a anti back-up valve in most dishwashers, but they are not totally effective against water from the sink coming back into the machine.
Get yourself some bread ties and get that hose up as high as you can under the sink so that it comes out of the disposer, goes up, and then back down to the dishwasher. This will also prevent crud from getting accumulated at the end of the drain hose where it connects.
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1 Answer


The dishwasher drain line that connects to the garbage disposal or pipe under the sink should be looped above the height of disposal or pipe to prevent
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Most dishwashers have some form of internal backflow preventer inside the water sump assy..
Yours may be degraded or stuck open.

Jan 16, 2010 | Dishwashers

2 Answers

Dishes smell like wet dog hair when cycle ends

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1 Answer

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1 Answer

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I am not a repairman but have installed several duel drawer dishwashers. Most dishwashers have a check valve preventing backflow. Water under pressure will always follow the path of least resistance and in your case it is going into the upper drawer. Be sure the drain is open and flowing easily under your sink whether that be the disposal or a TEE. It may help if the drain line is elevated as high as it can go under the sink just before it reaches the drain. How often do you use the top drawer? Perhaps run a cycle on the hottest cycle without dishes to attemt to clean or force through any contaminants in the check valve through into the drain. Hope this helps, Ken

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