Last Ditch effort to see if someone can help me with my KDM-21

[joeypete]

As in my previous post, I still have my KDM-21. I had purchased a new Bosch but the installer failed to contact me and after looking at my Hobart, it worked fine so I figured I'd keep it...and cancelled the order.

It has worked fine for the past 3 weeks until the other night when I started having issues again.

Tonight I ran a full cycle...meaning from start to finish on the timer. The Soak and Scrub cycle.

From what I noticed, the machine is having issues with draining. Every wash segment ran perfect. Here's an overview of what happened:

Start of Soak and Scrub...pump came on like it was supposed to...filled with water and washed. After it filled it shut off to heat the water like it should. After heating it washed for 3 minutes as it should...heated the water again...washed for 3 minutes. It then began to drain and the motor shut off. The timer kept ticking away. I didn't touch anything. It got to the point where it would fill again for the first full wash segment. The tub was mostly full of water so it filled until the float stopped it....the timer kept ticking and it was a bit before it switched over to water heating mode. Very brief heat period and the detergent cup opened. It then washed the full 10 minutes with no problems. Again it went to drain, motor kicked in for 1 or 2 seconds then stopped. Timer ticked away until it was time to fill again for the first rinse. It filled to the full amount then began washing like normal for 5 minutes. Stopped and began to drain. This time it drained completely. All normal to next fill for the main wash segment. Began washing, the detergent cup opened. It washed for 10 minutes no problems. Drain after this was also successful. Next it filled for the final rinse. Motor ran for the normal 5 minutes no issues. It stopped, began to drain and same thing as earlier, it stopped after a second or 2. I let the machine continue to the dry portion. When the fan kicked on I hit the Cancel button. It did not drain the water out...the motor never kicked in. I opened the door to reset the timer and hit Cancel again. It did not drain the water again either. I let it sit for several minutes and tried Cancel again. This time it drained the water completely.

So from what I can tell the machine is failing during the DRAIN segments. So I have to figure out why it's having issues draining. More specifically why the motor is actually shutting off when it goes to drain.

Going back a few months before this started, I began to notice a loud gurgling noise coming from my sink drain when the machine was washing. My machine drains into my garbage disposal. I did research and read that the check valve can go bad ( the thing with the rubber flap in it, I think this is the check valve?). It no longer makes any gurgling noises. So first question is if the check valve has failed, would that cause the machine to actually stop the drain process or would it continue to try and drain but no water would get out? If it does not stop the motor, then what other component should I be checking that controls the drain portion? Could the timer be at fault? I don't even know if this machine has a drain "solenoid". It doesn't seem like the motor is bad if it's washing ok, right? I dunno.

I really appreciate everyone's help. As excited as I am to get new appliances, this dishwasher has a spot in my heart and I've had a huge amount of anxiety with the idea of having to get rid of it. So if anyone could help I would be very happy.

Thank you very much!

 

[stevet]

Draining your energy!

Okay, Joe,
Let's get this thing fixed once and for all. A few questions.. you said it drained after the first soak/prewash. So we know water is going down the drain right? Is it going down with a decent amount of pressure? If not, then maybe something is caught in the elbow that channels the water from the pump down into the drain hose and causing the motor to overheat when draining due to back pressure.
Next, when it goes to drain and fails, do you hear the motor trying to start to turn to drain? Like a straining hum but no action? Then it cuts out which would be normal if the motor doesn't start as the windings will overheat and cause it to stop on thermal overload which was mentioned in your other thread. If that was the case, that may explain why, after washing, it will try to drain again and then stop. The motor has cooled down enough to run and then overheats again. And it doesn't take long for the windings to overheat.
I would replace the start relay as they do sometimes fail and the relay works for both forward and reverse. It is the black plastic device that has the blue, pink and black wires on it with the copper colored coil on it. Sometimes it is something that simple.

As regards the check valve, when they fail, it is usually in such a way that it will always allow the water to flow out and if it fails, whatever water is in the drain hose, it will get sucked back into the machine when the motor turns in the washing direction, hence the gurgling sound you hear.
Regardless, it would not directly cause the motor to overheat, but maybe something in the disposer wound up getting sucked into that elbow I spoke about above. You need to pull off the pump parts inside the machine down to the level of the drain impeller and you will clearly see what I am talking about. I don't think it is a timer problem and it is certainly possible that the program switch could be starting to fail and not sending the power thru the circuits properly to make the motor reverse all the time. After all these years, putting in a new switch may not be a bad idea.

And one other thing you may want to do. Make sure the motor is clean and not dust clogged preventing the motor from cooling itself when it is running.

See if any of this helps and let me know if you need any parts for it. I am tossing many of the parts I have as it is time to clean out once and for all prior to selling our home in the next few months.

 

[joeypete]

Stevet! Thank you so much. I was hoping you'd respond since you are the Hobart expert! haha

When the motor stops after trying to drain, I don't hear anything. It just shuts off.

As far as the water flow...yes it goes out with quite a bit of force. When it was draining, I looked down the disposer and the water was coming out at a good clip. It didn't take long to drain at all.

I'll take a look at the internals of the pump to see if anything is stuck. I had to take it apart a while back when I made my interior view videos....when I discovered that the lower spray arm wasn't moving hardly at all! It was really dirty and gritty. Hopefully I didn't mess anything up when I took it apart.

Where exactly is this elbow you are talking about? I just want to make sure I find the right area.

Thank you again for your help!

 

[joeypete]

I took off the the components down to the drain impeller and I did not see any blockages. I did pull out a small piece of ceramic, but it was in a channel and not near any drain area so I don't think it was an issue.

After I put it back together the spray arm doesn't spin as freely though...it spins then stops. Is that normal or should it spin freely? I just don't want to happen what did last time and the arm wasn't spinning during the wash. Maybe I tightened the wash impeller too much? (Edit...it does seem to spin pretty well. If I spin it, it will go a few times around then stop. It just felt a bit tight. Before it was spin really fast is all).

I also ran a Rinse/Hold again and it ran without issue. I then hit Cancel and it drained without issue. My next wash is tomorrow night so I'll see how it goes. If not then:

I guess the next step would be to replace the program switch and start relay to see if that helps?

If you have either of those parts I'd be happy to buy them off of you Steve. According to my parts diagram the relay is part number 242745 and the program switch is 242489. My switch has the 3 wash buttons and then 4 option buttons.

Let me know your thoughts...or anyone else for that matter.

Thank you![this post was last edited: 10/9/2018-08:12]

 

[combo52]

Hi Joe, you likely have a main motor problem.

You can try changing the motor start relay as Steve suggested, but I would start by checking the resistance of the motor windings, the wash winding and the drain winding should be the same, also check the run main winding for proper resistance and any shorts to ground.

John L.

 

[joeypete]

Thanks John! I’m not sure where those are though I downloaded the repair manual, is that info in there?

 

[combo52]

Yes You should find the resistance [ ohm values ] there, if it is not there I can measure the resistance of a KA motor here and post the information.

 

John L.

 

[joeypete]

Yeah I didn’t see anything but then I’m not familiar with this stuff. I know how to use a multimeter but could you explain where the windings are and where to test them to? Sorry I’m a little green in this area lol.

 

[joeypete]

Update

So the other night I took off the lower panel to inspect. I didn't see any signs of burnt wires or anything else "bad". I took off the start relay and cleaned the wires and connectors and also took off the ground wires and cleaned those and reinstalled. Looking underneath this thing you would never guess it's 33 years old. It's very clean! Very very little dust on the motor but I did wipe off what I could.

Last night I ran a Light Wash and it did perfect until the final rinse. Started to drain then stopped. Again the Cancel feature didn't work right away either...at least the drain segment. I let it sit for about 15 minutes and tried again, and it drained.

This morning I ran 5 Rinse/Hold cycles right in a row and it did not fail once. Filled, washed, and drained perfectly each time.

Now I'm certainly not an expert but it seems weird that it can't get through a wash cycle without failing but it can do 5 Rinse/Hold's right in a row without issue. To me that sounds like something is wrong in either the timing or the program switch.

One thing I remembered was over a year ago I ordered some butyl mats to put on the door to reduce noise. I also put some in the control panel area. Like a moron I forgot to turn off the power and my screwdriver hit the program switch and sparked. (It's also scared the bajeepers out of me). Obviously it wasn't something catastrophic because it's worked fine up until now. But perhaps it caused enough damage that it's deteriorated over time.

So today I'm going to take off the control panel to inspect. Perhaps disconnect the program switch and clean it and use some silicone spray on the buttons. I think I'm going to get a new program switch anyway. I found an NOS on ebay for cheap so might as well try.

I don't know how this machine works exactly but maybe there is an issue on the side of the switch where the wash programs are...and perhaps the Cancel is connected to those?

Again...I'm just brainstorming and trying simple things before I decide to replace the motor.

Any thoughts would be appreciated!

Thanks again.

 

[joeypete]

Well....

This might have something to do with it. :-/ It’s on the Normal cycle button. Also the purple wire next to it was unplugged!

Any way to fix this?

 

[joeypete]

Also this ground wire was completely gunked over.

 

[stevet]

Eureka!

I think you may have found the problem. Try connecting the wires back to their respective terminals and try the machine. It may start working just fine. Then try and find a new switch and keep it for a spare or install it so you don't have to worry anymore about the old one.
I would have to find a wiring diagram which shows the purple wore and see if it went to the start relay and if it was the cause of the problem. If I can get to the manual, I will let you know.

 

[joeypete]

Yahoo!

I ran a Light Wash tonight and it completed the whole cycle! Hopefully that was the issue haha. I'm thinking that maybe that purple wire was loose and when I pulled the switch out it came off. Weird that it would be loose, they aren't exactly easy to get off! But something worked tonight.

If it keeps working ok, I'm going to replace the drain impeller gasket...the one that is underneath the silver U shaped plate over it. It was completely trashed when I took it apart. Yes I plan on getting the new switch too. Like you said, not a bad idea to replace it. Especially while I can find parts.

Thank you again for all your help.

 

[johnb300m]

Yay! The prognosis is looking real good with these things listed, addressed.