Thread Number: 78637  /  Tag: Vintage Dishwashers
Maytag WU900 question
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Post# 1026359   3/5/2019 at 21:22 by Jasonlittle (Southern iowa)        

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OK. So I got this dishwasher a while back and have just had it sitting to the side waiting for the modern one that I have to quit. Well I finally got it put in over the weekend and I have to say I am not so sure how I feel about its performance. I canít believe how little time it takes to wash the dishes. My other one would run for about four hours. It seems like this one only runs for like an hour to an hour and a half if that. And that was the heavy wash !!! Plus the dispenser door does not open. I can hear a loud buzzing sound and Iím sure thatís what is going on. And it does not seem to be cleaning the dishes to well. Thereís a lot of stuff in there that resembles sand. This is the first time Iíve ever messed with a vintage dishwasher. I have lots of experience with washing machines and dryers and stoves. But Iím kind of lacking in knowledge with this dishwasher and not sure what to do from here. Is this normal to have such a short wash cycle. It fills up then washes for a while then drains. It repeats this approximately four times on the heavy wash. It never fills and runs for a extended time period. Iím not sure if somethings wrong with the timer or not? Was hoping maybe someone on here could explain how this machine is supposed to operate ?

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Post# 1026372 , Reply# 1   3/6/2019 at 00:49 by Cam2s (Nebraska)        
Maytag RR

Maytag dishwashers are excellent cleaners. I have a later direct drive portable unit. My built in Bosch can out perform it but just barely. Regular daily loads should come out sparkling. You more than likely need to clean out the micro mesh filter, a small amount of build up can lead to a large performance loss. You have to unscrew the wash tower, then lift the wash arm off. Then there are about 6 bolts that hold the pump cover on. Also a good idea to check the filter backwash arm while itís out. Being a vintage unit the circulation segments are only about 10 minutes long. If you use the temp boost you can extend out the main wash until about 15-25 minutes depending on your incoming water temp. Being that you have TOL all pushbutton unit it may be baked into one of the cycles or a stand alone option...would need to see the control panel to tell. The detergent dispenser is a spring loaded mechanism fired by a bi metallic strip. You can pull the front panel off to access it. Given that you can hear it buzzing and given the open position pictured I would say the spring is broke. Another item that will affect the performance is the actual detergent itself. Modern detergents, especially tablets are designed for longer wash cycles and donít do as well in a vintage machine. Many here will say you need phosphated detergent, I would say at least use a high quality powder and youíll be fine. One last item with this machine is itís unique racking system. These are referred to as reverse rack dishwashers as Maytag inverted the traditional racking layout. Glasses and such go in the bottom and plates and such go in the top. The important thing to remember is that there is a full size upper arm on the roof of the machine. You want the soiled surfaces to be able to get cleaned by the upper wash arm with supplemental power coming from the tower below. The racking is not as flexible as other machines, but if you master it you can really fit a lot of dishes in and be rewarded with superior cleaning in both racks.

Post# 1026382 , Reply# 2   3/6/2019 at 03:30 by askolover (South of Nash Vegas, TN)        

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Older dishwashers could get the job done in less time because they move tremendous amounts of water inside.  Both my Maytag and Kitchenaid can be finished in an hour easily and everything will be clean.  I still use chlorinated powder detergents because they were designed for them.

Post# 1026395 , Reply# 3   3/6/2019 at 06:51 by combo52 (Beltsville,Md)        
Maytag RR DW Performace

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Differently check the things Cameron suggested, but also check to see if the machine is getting enough water with each fill, it should be filling with at least 1 1/2 gallons each time it fills, if it sounds like there is not enough water in it stop it after it fills and add around a gallon of hot water and see how it sounds.


You also must have a working detergent dispenser, I have very good results with the premium detergent tablets in our vintage KAs and WP DWs, put one in the main wash cup and also use a cheap chlorinated liquid or powered detergent in the first open cup as a prewash. Unless you have very soft water or a water softener system you will not get good results with regular powered or liquid detergents today as they no longer contain phosphates.



Post# 1026398 , Reply# 4   3/6/2019 at 08:18 by gansky1 (Omaha, The Home of the TV Dinner!)        
Beautiful dishwasher!

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I believe the Maytags (at least earlier models) had the det dispenser actuation dependent on the load on the motor and troubleshooting mentions a shortage of water (as John said) and also checking the drive belt for possible sources when the dispenser won't open.   I think I have the service manual for this series, I will check tonight and post a couple of pics if so.

Post# 1026399 , Reply# 5   3/6/2019 at 08:45 by peteski50 (New York)        
Maytag wu900!

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I hope you get this restored they were awesome dishwashers. I have a friend that had the wu300 and it was a powerhouse!

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Post# 1026400 , Reply# 6   3/6/2019 at 09:06 by Jasonlittle (Southern iowa)        

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Thanks for all the information. I actually have already removed the spray arm and cleaned the filter beneath it. There was a lot of gunk down in there and I ran it through several cycles trying to get it rinsed out. It was very loaded down the first time I used it and Most of the dishes got clean. But almost all of them had sand like grit on them that I had to wipe off with a towel. The detergent dispenser door moves stiffly and almost feels like there is the gunk buildup in it that needs cleaned out. But it does not feel like it has any spring at all. So Iím thinking that the spring might be broke like mentioned. I know where there is a portable version of this sitting out behind a building. Itís been there for a while but until now I never had any reason to ask about it. But I know the lady who owns it and Iím sure she will tell me I am more than welcome to take it. I figure that would be a good donor machine.

Post# 1026401 , Reply# 7   3/6/2019 at 09:08 by Jasonlittle (Southern iowa)        

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Also another thing I noticed is it seems to have a struggle getting the Motor up and going after it has sat for a few days. And it seems to be labored starting every time it shuts off during the cycle too although it does start OK it just sounds like it struggles . I did check the pump pulley to make sure it wasnít hard to turn and it is not. It turns freely so I am afraid that the motor is starting to get week. Iím hoping this donor machine I am after will have a good motor also.

Post# 1026410 , Reply# 8   3/6/2019 at 12:24 by countryguy (Astorville, ON, Canada)        

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I had a Maytag WU700 which is the model below the top of the line WU900. It had 5 push buttons and a timer dial. It was a real workhorse and got everything clean and fast although a bit on the noisy side. There was a Rinse/Hold cycle and 3 wash cycles - Light (67 minutes - RWRRD), Normal (75 minutes - WWRRD) and Heavy (87 minutes - WRWRRD).


Post# 1026415 , Reply# 9   3/6/2019 at 13:47 by potatochips (Nova Scotia)        

I have a WU901, its an amazing performer. 


I too had issues with the detergent dispenser but that was solved by shaving some plastic away on the cam gear that holds the dispenser shut with the bi-metallic strip. Stupid setup if you ask me.


It is very normal for this thing to blast through the cleaning cycle at light speed, the rinses and pre wash are only 5 mins each, and the main wash is 13 minutes. If you select Power Boost, the main wash is extended to 26 PLUS heating time to 140F. I did some wiring on mine to bypass the 13 minute wash extension as just heating to 140F alone adds about 10 minutes. 


Overall this machine is a real performer, space is insane if you load it right. It can clean very, very well. 

Post# 1026457 , Reply# 10   3/6/2019 at 21:52 by Jasonlittle (Southern iowa)        

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OK thanks for the info. Iím hoping that it will get better as it goes. It was pretty dirty and Iím sure as time goes on it will get the dirt rinsed out. Iím hoping this next time will be better. I plan on opening the door up this weekend and check it out the dispenser. I have another one Iím going to ask about as a parts machine. If I get it it should have a lot of spare parts for this one

Post# 1026525 , Reply# 11   3/7/2019 at 20:59 by Jasonlittle (Southern iowa)        
Donor machine

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I got this today. The outside is in horrible condition but the detergent dispenser works like new and the racks are in way better shape than the ones I have currently. They just have a few small rust spots. The ones Iím using currently are almost rusted in half in places. Iím going to remove the motor and pump as well. Pretty much anything I could possibly use on mine and then scrap the rest as it is completely destroyed. Even the inner tub has been damaged. Something has hit this machine hard.

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Post# 1026526 , Reply# 12   3/7/2019 at 21:40 by bigalsf (Salt Lake City)        

Congrats on finding a donor machine. The inside looks fairly clean; this is a good indication that the pump is also clean & in good condition. If it is you should take it.

Based on what I read in the thread it sounds like not enough water is circulating. If the micro mesh screen is clogged it will significantly affect performance. Another item to check is the nylon ring seal/bearing in the pump cover. There are two nylon rings which fit over the back wash arm and seal the center opening in the pump cover; they interlock one over the other. If these rings are out of position, worn, or missing this will also affect performance as the lower arm will not turn at the correct speed; it will move very slowly (or not at all).

Hope this helps. Good luck!

Post# 1026534 , Reply# 13   3/7/2019 at 22:04 by Jasonlittle (Southern iowa)        

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OK thanks. I plan on taking it apart this weekend and really going through it good. Plus installing some of the replacement parts. And yes I plan on getting the pump the belt the motor the water valve and pretty much everything but the cabinet. Anything that could possibly be needed in the future that isnít damaged. The rest will be scrapped because it all beat up. The top has warped a little but Iím going to try to straighten it up and even use it for something. Maybe a cutting board or a shelf?

Post# 1026565 , Reply# 14   3/8/2019 at 08:15 by askolover (South of Nash Vegas, TN)        

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I used the top off my converted portable Maytag as the top for my Miele's pedestal!  Worked great!

Post# 1026990 , Reply# 15   3/13/2019 at 19:29 by electronicontrl (Grand Rapids, MI)        

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It sounds like you are on the way to getting your Maytag dishwasher restored. Once you see the capability of this machine you will love it!

Post# 1027057 , Reply# 16   3/14/2019 at 13:37 by Jasonlittle (Southern iowa)        

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Thanks. Yeah Iím loving it. I just ran it through the second wash and it did much better this time. There was no Sandy like stuff on the dishes this time. I suppose it just needed to get all the dirt washed out of it from sitting for a while.

Post# 1029396 , Reply# 17   4/9/2019 at 21:24 by reactor (Tennessee)        
micro-mesh screen

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Jason, if the previous owner had hard water, you may find calcium carbonate (calcite) built up on the filter. You may wish to remove it and soak it in white vinegar, CLR or LimeAway.

You may have done this already, but I would also recommend removing the lower and top wash arms and inspecting the small holes (jets). Occasionally hardwater deposits can clog these, or a piece of food wastes somehow works its way past the filter. Inserting a large sewing needle into the jets will usually dislodge any blockage. It wouldn't hurt to run a cycle with CLR or LimeAway, after you have done this, for a general overall cleaning. I have found Cascade Platinum dishwasher cleaning tablets also work well for an overall cleaning, if calcium deposits are not heavy. It's about four dollars for two tablets.

A Maytag Reverse-Rack gives almost perfect washing results, so anything less than this indicates some more work needs to be done.

It's a beautiful machine. Hope you get it running to full capability!!

Barry W.

Post# 1029557 , Reply# 18   4/10/2019 at 22:37 by Jasonlittle (Southern iowa)        

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Thanks reactor. Yes I have got all the bugs worked out of it now and it has been working wonderfully. I have removed all the internal components and cleaned them. I think it just needed to get all the dirt rinsed out. The dishes have been coming out sparkling clean.

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