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The Home Smithy
The Home Smithy, Home Appliance Technician
Category: Appliance
Satisfied Customers: 9619
Experience:  30 years repairing appliances
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My Bosch SHU9916UC dishwasher washes the bottom rack fine,

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My Bosch SHU9916UC dishwasher washes the bottom rack fine, but not the top. I took apart the gray channels to the sprayer under the top rack, and found no blockage. I cleaned some bits of debris (corn kernels, aluminum foil, fibers,etc.) from the very bottom, but the situation didn't improve. The sprayer moves with the top rack, and seats against the gray channel in the rear for water flow. There is no blockage. Is it improperly sealing? That's my theory. What's the fix or possible other solution?

Hi. Welcome to JA.

The sealing of the upper spray arm should not change due to an impropper fit at the connection. The basket will not allow the door to close properly unless the connection is correct.

The only thing that cpould effect the cleaning ability of the upper spray arm is if the sprayer where it connects is worn out. It can cause a low pressure condition as all the water leaks out at the swivel point. It can also cause the arm to not turn. The arm not turnning is the most likely problem as far as the arm goes. This will be noticeable as there will be considerable slop at the connection point.

If the spray arm is ok, then the most likely problem will be a damaged or worn out impellar. This repair is not one that I recommend a novice DIYer attempt. It involves considerable disassembly of the unit.

I have posted a picture of the trouble shooting chart for your unit below.

Please let me know if you require further information.

Best, THS

graphic



Edited by The Home Smithy on 5/1/2010 at 7:36 AM EST
Customer: replied 7 years ago.
This unit is four years old. I have no reason to believe the impellar is damaged or worn out. Is there any way to check if this is the case?
By removing the filter you should be able to look at the impellar blades.
Customer: replied 7 years ago.
I did. Removed the filters and the impellar blade cover. I do not see any damage. When I turn the blade, it has resistance, then quickly releases and turns a couple of times, so I don't think there's a broken belt, or whatever drives it. Could it be anything else, in your experience? I already had the flow chart.

Ok.
If you felt resistance in the impeller and then it turned freely after the first turn or so then you may still have a problem with the impeller or the motor that drives it.

The resistance of the impeller should be consistent at any point in either direction.

Try this; try spinning the impeller both directions. Spin it more than a few times all the way around, both ways. Do that a couple times to be sure that it doesn't again become harder to turn.

If it does then again further disassembly will be needed to determine what is causing the resistance.

If the motor is having to drive the impeller with resistance applied to it then the lower speed of the impeller turning will greatly reduce the amount of water pressure sent to the spray arms. This will seriously impact the ability of the unit to clean the table ware on the top rack while still doing a good job on the lower rack.

If it checks out as good then run the unit for as long as it takes to fill it and begin the wash cycle. Stop the cycle and set it to drain the water and turn off. This will warm up the components and may show something.

Once again check the impeller. If it is free then it should be ok. The first time may have been a coincidence. If you again feel resistance and then a freeing of the impeller something isn't right. Further disassembly will be needed to accurately diagnose the unit.

Please let me know what you come up with.

Best, THS



Edited by The Home Smithy on 5/1/2010 at 7:13 PM EST
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