Why does dishwasher only drain when unhooked from sink?

Why does dishwasher only drain when unhooked from sink?

Just bought a new place. Wife did load of dishes in dishwasher and then noticed about one inch of water had not drained. I did some research and assumed there was a Clog someplace so I took the thing apart and found nothing. I called a handy man who told me to unhook the dishwasher tubing from under the sink and try to drain dishwasher. Drains without hesitation. However when I plug back on its the same problem. Sink does not back up when running. Tubing under sink has the rise and fall before connection.

Asked by: Guest | Views: 259

Total answers/comments: 2

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bert [Entry]

"Hi @sleepincow ,

The dishwasher drain hose must be connected before the P trap, not on the sewer side of the trap. The water ""held"" in the P trap prevents gases coming back into the dishwasher from the sewer.

The high loop is to prevent potential backflow of water into the dishwasher and to prevent improper drainage of water."

bert [Entry]

I had same problem. Dishwasher would drain when not connected. Check your plumbing that the dishwasher connects to under sink mine was clogged up with fat and grime, I took it apart cleaned all tubing under sink and it worked great.