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FIXED Whirlpool Dishwasher WDT790SAYM3 - Squealing

GameEngineer

Premium Member
Joined
Oct 15, 2012
Messages
11
Location
San Diego, CA
Model Number
WDT790SAYM3
Brand
Whirlpool
Age
6-10 years
The dishwasher began squealing during the initial phase of washing and at times during the middle. Sure sounds like a pump squeal. Its been doing this for a while but it sounding louder. More than likely it will fail at some point. I want to be sure what I need to replace before I just order a new pump. I am not sure if there is a pump that fills the washer because the noise happens immediately when hitting Start and a few times after. There is no squealing during the wash cycle and the dishes are getting clean with plenty of water evidence after the wash is complete.

Are there more than one pump in a dishwasher? If so which one would be the done that operates at the very beginning?

Trying to do research on this washer I am seeing a circulation pump and "pump and motor assembly". Same thing? I also saw it might be the water inlet valve with a bad diaphragm.

-Steve
 
Last edited:

rickgburton

Appliance Tech - Moderator
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Messages
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Location
Murray, Utah 84107, United States
... the noise happens immediately when hitting Start
I believe on that model the first thing that turns on is the drain pump/motor
whirlpool-pump-drain-wpw10348269-ap6020066_01_m.jpg
 

GameEngineer

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Joined
Oct 15, 2012
Messages
11
Location
San Diego, CA
Interesting! I completely discounted the drain pump because I thought it didn't need to drain yet. Thank you for the direction. As a debugging check to see if it is this part would it be a bad idea to close the inlet water and disconnect this pump and turn on the dishwasher for a few seconds to see if the squeal goes away? Not sure what happens if no water is allowed to come in and the drain pump has no load.
 

rickgburton

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There's really no point to removing the drain pump/motor unless you have a replacement ready to go in. The only thing energized when you press the start pad is the drain motor. When the drain pump/motor stops the fill valve is energized and then the wash motor.
 

GameEngineer

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Joined
Oct 15, 2012
Messages
11
Location
San Diego, CA
That has to be it, thank you so much! I was actually leaning toward purchasing a different component which was 3X the cost of the drain pump. I am a software developer involving hardware and I'm familiar with writing hw drivers and higher level apps that control devices (re: my username, I teach game sw development on the side!). I'm curious why they decided to start the drain pump first? Is it to drain any existing water in the tub before adding new water for the current wash cycle? The reason I discounted this pump was because it didn'tmake sense to me that would be the first thing to start up right after pressing the Start button.
 

rickgburton

Appliance Tech - Moderator
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Messages
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Location
Murray, Utah 84107, United States
.... Is it to drain any existing water in the tub before adding new water.....
Correct, it's usually 2 minutes but varies between manufactures.
 

GameEngineer

Premium Member
Joined
Oct 15, 2012
Messages
11
Location
San Diego, CA
Ok determined it's not the drain pump but the fill valve. The solenoid is whining. The drain pump sounds and acts fine. I debugged it by starting the cycle then canceling it which forces a drain. And the whining during the fill changes pitch when the line is pinched.
 

GameEngineer

Premium Member
Joined
Oct 15, 2012
Messages
11
Location
San Diego, CA
Thank you again! When I was checking it out one more time yesterday this time I pulled the lower panel. the drain pump was going first but it was so quiet it was not noticeable the times I was listening before. When the fill started I could locate the sound easier and it was coming from the fill valve near the front. Even touching it or pitching the fill water line while it was squealing changed the pitch of the squeal.

-Steve
 

rickgburton

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Steve, take the supply line off the water valve and clean the screen. You may not need the valve.
 

rickgburton

Appliance Tech - Moderator
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Don't open the package and you should be able to return it if you don't need it.
 

GameEngineer

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Joined
Oct 15, 2012
Messages
11
Location
San Diego, CA
Valve installed and no more squealing. I replaced the water hose too. It had all kinds of deposits inside near the water valve at the wall. The screen on the old valve was dirty but I went ahead and replaced it. Thanks for the help!
 
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