Dishwasher overflowing out bottom

My dishwasher will run normally for about 15 minutes. At that point it begins to overflow out on to the floor. Looking in the dishwasher the tub is filled with water and there is still water flowing in. When I cancel the cycle it drains fine. Also, the float seems to be moving freely. Any thoughts on which part needs replacement?

If you cancel the cycle and the water stops, then it sounds like you have a bad float switch. First turn off the power to the unit. You will need to go to the toe panel of the machine and remove the panel. Next locate the float switch under the machine. With a multi-meter test the switch for continuity. NC should read closed, and NO should read open. If the switch is good make sure the float leg is making contact with the switch, and that the switch housing is not broke. If the switch is bad, here is the part you will need. I’m also attaching a link to the diagram for you to use.
[part]AP4422617[/part]

Fill and overfill parts replacement parts for MAYTAG MDB7851AWB0 UNDERCOUNTER DISHWASHER | AppliancePartsPros.com

Ok, I finally got a friend to come over with a multi-meter. He tested the float switch and said there was continuity with the float switch both up and down. Looking at the switch housing it doesn’t appear to be broken. I also tried resetting the breaker and thought the problem was solved - this time it ran for about 30 minutes and again started leaking out. Again it drained fine when I cancelled the cycle. Any thoughts on what to try next?

If you read continuity both up and down, then the switch is bad, and will need to be replaced. You will need to order the part listed above to fix your problem. It should have read closed when down and open when up. Hope this helps.

I ordered the housing/float switch and replaced it. By the way it was deliverered in one day. However, after running about 5-10 minutes into the cycle it started leaking again this time from the other side (left) where the water line comes in - which I think is the valve. Is it a bad valve? If so any tips on replacing it.

Note: my water supply comes in through copper piping.

What does the water level look like when it starts leaking? Do you see any soap suds inside the machine? Did you check and make sure the float was moving freely up and down, and the switch was making contact with the float stem? The valve is located in the bottom of the dishwasher. Usually if the valve sticks open, the only way to stop the water flow is to turn it off at the shut off. It could be a bad valve. I would check the door seals, and look for soap suds, and make sure the float is moving freely, and making contact with the switch. Hope this helps. Let us know what you find.

I tried to run a cycle again to assess the questions you posed in the previous post. Within a minute there was a leak in the valve/valve terminal area. The leak did not stop upon cancelling the cycle but did once I turned off the shut off valve under the sink. Also, everything with the float appears to be ok: it moves freely and is making contact with the switch.

I think you have found your problem. If you could not get the water to stop until you turned it off at the shut off, then the valve is bad and will need to be replaced. Here is a link to the parts diagram page, as well as a link to the part. Hope this helps.
[part]AP4456759[/part]

Fill and overfill parts replacement parts for MAYTAG MDB7851AWB0 UNDERCOUNTER DISHWASHER | AppliancePartsPros.com

I just ordered the part. Any way you might be able to advise me on how to replace it. Thanks.

These are not hard to change. Just remove the toe panel and remove the water supply line and the wires to the valve. Remove the screws mounting the valve to the frame. Next, remove the fill hose clamp and hose off the end of the valve. Reinstall in reverse order. Hope this helps.

Jeff,
I wanted to let you know that once I recieved the part I followed your steps and everything seems to be working like normal now. I really appreciate your help in troubleshooting this issue with me. You were right it wasn’t that hard to change.

I did have one more question though. Does it matter if the valve isn’t mounted to the frame? My water supply line is copper and it comes in at a different direction from where it “should be” mounted. The metal bracket is resting on the floor and it appears to be sturdy enough and again everything is now functioning the way it should.

Thats great! Glad we could help!! If you can mount it to the frame it would be best. That will keep it from moving around and shorting out aganist something under the dishwasher. If you can not mount it, I would try to secure it from moving around. Again, Thank you for doing business with Appliancepartspros.com