Neff Dishwasher keeps draining

renMIke · Jun 12, 2012

Hello,

I've recently observed a problem with my Neff dishwasher (model #: S5456X2GB/42). This is a fairly old unit at 8 years, but it has been trouble free all that time.

The symptoms are that towards the end of the program it drains the machine and appears to not sense when the water has gone as it keeps on draining. This extended draining process carries on until the end of the program and beyond. It's not known if there are any missing steps in the programe but the dishes seem to have a salty residue left on them and sometimes there is a white reside in the base of the machine. Left unchecked the drain cycle carries on indeninitly. To stop the program I need to force the reset and then turn it off.

So far I have tried:

Cleaning the machine buy taking out the drain components in the base of the dishwasher.
Checked that the impeller is not blocked/clogged.
Removed the left hand side to examine the float mechanism controlling the water input. This was quite dirty and so was cleaned.
Checked the overflow sump (in base on left hand side) to see if it contained any water and so could be requesting the machine continue to drain. It was found to be empty.
Just in case I'd mistook the sump for something else i've tilted the machine forwards and backwards to drain any water out (only water from the pipe work exited the machine).
Checked the switches on the left hand side to listen if they audibly clicked when activated. They did.
Checked the switches on the left hand side to see if they broke/made a circuit when activated. They did.
Watched the machine run without the left hand panel on and visibly saw the water enter the machine. In doing so it triggered the switches to presumably avoid flooding the machine.
During the running of the machine I manually activated the float mechanism and it successfully stopped the input of water for the time it was activated.
Removed the bottom pannel to see if anything obvious was wrong there. Couldn't see anything obvious.
Removed the right hand panel to see what was there. I was able to observer the motor running at this stage.
Removed the circuit board to look for burnt spots, but none were visible.
Searched the Neff, Bosch and Seimens web sites for clues, wiring diagrams, etc. to help but nothing has yet turned up.

I took photos at most of these steps in case they can help diagnose the problem.

My current theory is that there is a switch/sensor/sender somewhere in the drain that is not activating when the machine is dry but I can't find it.

Does anyone have any other theories as to what might be causing the problem or suggestions as to what i might test as i'm now stumped.

Thanks,

Mike

jtsplumbing · Jun 12, 2012

Hi Mike think you could be on wrong Thread, white goods , you may be better off on Electrical Forum, Have you spoke to Neff ?

renMIke · Jun 13, 2012

Fair point on the appropriate thread. I've used this site in the past for more typical plumbing issues and thought I'd give it a go.
I'll try an applicances forum to see if they can assist.

Thanks,

Mike

tamz · Jun 13, 2012

Maybe it is the change of life. My dishwasher played up for a while during this spell but went back to normal after a while :smile:

zzzjim · Jun 14, 2012

( Moved my 22yr old Zanussi , to diagnose an issue ,)
( found it was held together by gravity , steel straps rusted thru )

Try a hot vinegar + water rinse ( if Manuf Instr say its ok )

( Buy new if any health worries - since seen insides of a few )

renMIke · Jun 18, 2012

zzzjim said:
Try a hot vinegar + water rinse ( if Manuf Instr say its ok )

Seems like a reasonable suggestion. Nothing else seems to be getting it going so why not.
I've heard suggestions elsewhere to put 1 cup vinagar in a normal bowl and set it on the bottom rack before starting the programme. Does this seem suitable?