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Techdesk, Service Engineer
Category: Appliance
Satisfied Customers: 16409
Experience:  Whitegoods engineer working for a multibranded national company in the UK
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We have a Bosch dishwasher basic model which is not washing

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We have a Bosch dishwasher basic model which is not washing the upper tray properly. We have checked that the spinner rotates manually and the holes are clean, cleaned the filters, it drains OK and the pump is obviously working enough to clean the bottom layer. Have checked plastic piping is clear to the spinner. Any suggestions? David Bowerman
Can you post the E-Nr number of the appliance please?
If not on a label, it will be very faintly etched across the top of the inner door.

How old is the machine?

Customer: replied 4 years ago.

SGS 431(T?)02GB/06


Guessing it is 2006

OK, thanks for that.
Check the spray arm along it's seam to see if it's split.
If ok, run a wash.
During the wash, open the door and add a jug or two of water.
Close the door and continue the wash, check during the wash to see if the top arm is turning.

Customer: replied 4 years ago.

Thank you - the arm is not split, so will try the wash and jug of water.

The seals (a peculiar 2-holed silicone type rubber washer that 'floats' in the grey plastic case) where the top arm pipe engages on the top water feed do not seem very tight - is this normal?

yes, they only seal when the feed pipe pushes into them.

If the arms are not split, the feed pipe is ok and there's no blockage in the arms, it only leaves low level of water (shouldn't happen on your machine) or a weak circulation motor.

Customer: replied 4 years ago.

Tried the jug of water and it cut in the discharge pump within about a litre. There was already water all over the bottom pan of the machine, so I don't think low water level is the problem. Took off the lower arm and switched the machine on then opened the door and there was a healthy fountain of water squirting vertically up to the top tray. However, placed objects on both upper and bottom trays so as to foul the arms after half a rotation (having established direction of rotation) and then timed to see how long it took for the arms to get around - it was nearly a minute, which seems excessive. So is it a case of high water volume but low pressure from the pump?

Sorry, don't quite understand what you mean by a minute to rotate.
Is this for either arm?

Take the top and side panels off of the machine.
Look at the heater box, is there a motor attached to the heater?

Copy and paste the following into a new browser window for a picture of a heater with a motor. I only need to know if your machine has the motor fitted to the heater.

Customer: replied 4 years ago.

This is for both arms - each arm took that long to rotate. Then I noticed that one of the end spray holes was blocked, which I'm sure was clear when I previously inspected it, and managed to get out a large seed covered in fat and subsequently 4 or 5 others! So I presume the fat is gumming it to the arm so you cannot see them and then they dislodge and get stuck in the spinner hole. Am just running the machine without the spinner arms to try and dislodge anymore seeds that might be in the system. If this does not work, we will remove side panels to look at the heater as requested.

OK, you'll need to fully clean out the arms.
As you rightly suspect, debris could be in them, being pushed to the end and blocking the holes that propel the arms, then, when no pressure, sliding back into the arms.

Your heater doesn't show a motor but, if the arms are not the cause, it only leaves the heater as the suspect.

Customer: replied 4 years ago.

The heater is working because the water is now warm in the cycle. Arms blasted with the garden hose and are now rotating in about a second! So I think we have solved the problem - thank you and I feel a bit stupid!!

It's not the heat I'm on about.
On some machines, there's a motor on the heater that diverts the water to 1 arm at a time.

As you had already advised there was no blockage or splits in the arms, I wanted to check the drawings for your machine were correct, ie. no motor.

Glad you got it cleaned out, good luck with the test and the appliance.

Hope this helped
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