Question about Bosch 24 in. SHU43 Built-in Dishwasher

1 Answer

... calling Master_Tech Bosch Dishwasher SHU43C07UC

Master_Tech are you there ??

I wrote an essay earlier, which you can ignore (or read - i will paste it below). My Bosch dishwasher SHU43C07UC spray arms are not rotating. They spray (bottom's: up through the top rack; top rack's: full spray but wouldn't say forceful; top spray: weak umbrella), but no rotation. I plugged some of the top holes on the bottom sprayarm and indeed it will rotate... i am trying to find out what the problem was, thought it was related to house water pressure but don't still think that.

After posting my essay, I then read as much as i could find on websites like these and the suggestions i found were to clean out the waterlines and sprayarms.

So i went back to see if the spray arms were clogged (weren't) and started looking for waterlines and did this instead: took racks and sprayarms out and turned on dishwasher. The spray seems forceful enough out of the bottom and middle (backwall) jets and still weak from the top. But also, the spray fluctuates from strong to weak to strong to weak, 2seconds each. No odd motor noise, just this fluctuation.

Can you diagnose the problem ?? If I should clean out waterlines, I was thinking I should lay the dishwasher on it's back and access them from the bottom. Would it be only one line that exits out the bottom that might need to be checked ? I hope you can help. Thank you

[email protected]

[morning's post:

Hi, can I please get advice ? (Ready for an essay ? Just trying to be clear here, before I resort to paying troubleshooters that point the finger elsewhere...Thanks, Mary)

The plumber just replaced all water lines to the kitchen sink/dishwasher with 1/2" copper pipe, and there are about ten 90-degree bends in the 40' long line now (he replaced the no-bend gray flex pipe - - the kind known for leaking eventually; these are dedicated lines directly from the hotwater heater area to the sink, same as the graylines were) and so now I have anoticeable drop in water pressure at the sink. Now the dishwasher isn't cleaning. I was blaming this on the lack of water pressure, and started troubleshooting. This is what I found:

First, one fact on the house: The new hot water line to the sink is a spare only, i just discovered - untapped - so I can't blame this new 'dishwasher not cleaning' problem on it. See, the original homowner apparently had experienced a leak in the COLD water line under the slab (florida home) and ran the gray line replacement water lines, for BOTH hot and cold, through the attic to the sink and tapped both up. This created a loop in the hot water lines: the original under-the-slab line and the replacement grayline. The plumber and I had discussed the 'loop' setup the previous owners had set up, he said he would not change my setup, but I just discoverd today while troubleshooting that he left the new HOT copper line untapped. Therefore, the dishwasher is fed from the original under-the-slab water line only, and I can't blame the new drop in pressure at the kitchen sink for the dishwasher problem. I was about the call the plumber and have him remove some of the unnecessry 90's, but won't do that right now.

Troubleshooting the dishwasher:

To prove to myself that loss-of-pressure was indeed the cause of the problem, BEFORE I discovered the HOT was no longer served from a loop setup, I turned the dishwasher on with the door cracked open so that I could view the water flow.

I saw that water shoots out of the bottom sprayarm upward to 2"above the the bottom of the top tray, but the bottom sprayarm does not rotate.
I see that there are two holes on the bottom of that spray arm that, if there were enough pressure, would direct the sprayarmto rotate.
I taped over the top holes on the spray arm so that all water will be directed (mostly) out the bottom holes and cause sprayarm rotation and that indeed does cause the spray arm to rotate. At this point, I could choose 1) plug the upper holes and get sprayarm rotation or 2)plug the lower holes and get clean dishes only directly under the non-rotating sprayarm.
I had cleaned the traps meanwhile and had also removed both sprayarms in case I saw something blocking something - there were no blockages.
When I turned the dishwasher back on to check for rotation, I noticed that a lack of water in the trap/resevoir area means the pump has no water to pump and therefore water pressure is probably not a factor in rotation of the spray arms afterall. I had thought that the entire time a dishwasher operated, there was a constant feed of water through the water lines. I didn't realize that there is only initial feed of water and then it operates off a resevoir of water being pumped through the spray arms. (Is that correct?)
The upper spray arm only rotates intermittently, but has spray action.
The top spray (ceiling) has a weak spray.
My floor is slightly wet from watching the spray. (Just saying that to be funny - it's NOT wet from leaks - there are no leaks - I have the dishwasher pulled out.)
The dishwasher pump has some action: i hear it, i see spray.
My dishes are dirty because the spray arms are not rotating.

(I've never liked this $500 dishwasher.)

What do I do ??

I realize it could be proposed that the loop system had maybe helped the dishwasher perform and i have no arguement to counter that. There is, however, very effective pressure in the original under-the-slab hot water lines which feed the bathrooms, and they tapoff AFTER the kitchen sink hot tapoff.So there should be very decent hot water pressure still at the kitchen sink.

However, something i don't understand is, when i turn on the 'hot only' at the kitchen sink, why don't i see that same original 'under the slab' good pressure ? Does the kitchen sinkg's one-handle valve (hot and cold combined) not give a true 'hot only' output, allowing compromised pressure ? Or I have another 'mystery' problem.

I bought the dishwasher 4.5 years ago, and i read that there is a five year warranty on 'electronics' and on 'upper and lower racks (excluding rack components)' - will that help here ? Electronics ?

Do I a pump problem, even though there is spray ? Or what ?

Pullease help
Thank you

Posted by on

  • maryoooo Feb 02, 2008

    hey textoner, thank you for your answer. i'm soaked. how do tech's view inside and not get wet ? i was using cookie sheets on top and it was coming out the sides. earlier i had saran over the front. easier to get wet. or take the racks out, remove arms and cover opening with a dish, but i wanted to see how the arms were rotating

    naturally, i have more questions: i didn't know water level was a factor in performance. since i didn't know, it may be that i was causing the fluctuations in spray today. not so sure it wasn't performing badly all by itself, though, yesterday. just now i added water myself to bring it to the mark you mention (2" inside wall). spray was everywhere and spray arms were moving fast. no flucatuations in water flow at all.

    short of unplugging it, i don't know how to get it to begin a wash at the very beginning so i will run it through a drain cycle and then start fresh and see if it fills to the proper level all by itself. if it doesn't, then what is it that i need possibly ?

    i didn't clean any filters, you know, though. i only made sure the sprayarm holes weren't clogged. and i wasn't able to see any water hoses (like the resevoir re-cycle hose - there must be one of those right ?) accessible underneath to clean out. so all i did was remove everything INSIDE and put it back in after rinsing.

    you suggested a pressure switch, regulating water level - is that part 0430 on this link ? and since i just got soaked and the spray seems pretty good when the water level is adequate, does that eliminate your second suggestion of separated impeller ?

    and prior to replacing switch i would try your oil cleanout. is too much detergent a visible thing - is there visible evidence ?

    think i could take the bottom front panel off and find pressure switch o430 and replace it without having to take any moving parts apart ? or should i call a pro ?

    and thanks again for your answer

  • maryoooo Feb 02, 2008

    funny - thanks for the 2nd followup, too



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  • 130 Answers

Hello Mary, I checked on your dishwasher and what you have is a pressure fill dishwasher. This unit has a pressure switch to make sure the water level is correct. When the dishwasher is full of water (the indention that is around 2 inches in from the side walls and front) is where the water level should be out to. If the water isn''t out this far, then the pressure switch is shutting off early and not filling properly. I read your entire essay, it is perfect, so this sounds like an issue of either not enough water, or the circulation pump impeller has separated and not creating enough water pressure at the wash arms. Since you stated that you removed and cleaned the filters, that shouldn't be the issue. That is normally where I find this issue at is clogged filters, espically in hard water. I have seen results in the pass where too much detergent was used causing the pressure switch to shut off early. In those cases filling the detergent dispenser with cooking oil and running the longest cycle removes the excess detergent. It is proteins that the detergent is designed to break down. So quit worring about your water pipes, the issue is with the dishwasher. Hope this helps.

Posted on Feb 02, 2008

  • Anonymous Feb 02, 2008

    Well Mary, I just happen to have a plastic front that fits the dishwasher so I can see. Actually the pressure switch in on the left side of the dishwasher. You have to pull the dishwasher to replace the pressure fill assy. You can go to owns Thermador), at the top is Service, click on that, at the bottom is purchase parts, click on that. Now it reloads and shows customer accessories or service techs. Click on the customer link and the sight for quick finder will come up. You can look up the part and even order it direct from Bosch. The filter screens in the bottom need to be removed every 3 months and cleaned, they are at the bottom in front of the lower wash arm. If you need the pressure fill assy, part number is 263834 and it is in inventory. Glad I could help

  • Anonymous Feb 02, 2008

    Sorry Mary, I forgot to answer this question of yours. The circulation Impeller is fine. Your issue is the lack of water. You are doing so good at resolving this, you may want to take up dishwasher servicing. Glad to help.



6 Suggested Answers


6ya staff

  • 2 Answers


Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

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Good luck!

Posted on Jan 02, 2017



SOURCE: leaking

if you remove the lower sprayarm, you can see the mesh that covers the pump is held on by a series of screws. Are the screws loose? Mine were, I tightened them and no more leak!

Posted on Aug 25, 2007

Dov Dror

  • 641 Answers

SOURCE: dish washer

It could be a motor or a pump issue. The dishwasher has a motor that attached to a pump which forces the water up into the sprayer arms and during the drain cycle, it pushes the water out of the dishwasher. The motor (and pump) located beneath the dishwasher. Check if motor spins. In case it spins, the problem is with the pump ,in case it doesn't spin it could be a motor problem or a motor and pump problem. Good luck

Posted on Aug 31, 2007


Mark MacDonald

  • 2605 Answers

SOURCE: kitchenaid superba dishwasher does not pump water


Welcome to FixYa,

It may be a seized wash pump, worn wash impeller or simply a plugged up pump preventing a proper wash cycle.

The place to start for that is to pull the pump filter, spray arm and check for food deposit, broken glass, undesolved detergent and general water deposit built up in the sump well.

The key is to get in there and clean it all out, I`ve attached a link at the bottom that will show you how to go about it. It may not be your model, ( Most Whirlpool, Inglis, Kenmore, Kitchen-Aid, Jenn-Air ) but it is the same procedure.

When you`re finished run it through a test cycle and see how it goes.

Let me know how you make out and what you find.

macmarkus :)

Posted on Aug 19, 2010


  • 3247 Answers

SOURCE: too much soap used in

Looks like someone from fixya has already worked on this.

Not sure why it is still showing up as open problem.
It would be helpful if you are able to post a comment confirming the fix which Miele suggested.

Posted on Oct 29, 2010


  • 1 Answer

SOURCE: kenmore 587.1616 - upper sprayarm doesn't move -

remove chopper, clean screen on chopper.

Posted on Nov 23, 2011

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