Neff integrated dishwasher not washing properly

[echase]

Re: Neff integrated dishwasher not washing properly

I dismantled the diverter valve and it seems all OK with no cogs worn and machine does now run through an apparently OK cycle with both spray bars turning alternately. But I note that diverter can be assembled with the water control disc in 4 different positions which means the relationship between the disc and the cam that operates the switch by gears can be 4 different ones. How do I get it right? There is little hole in one gear that seems an alignment mark but not sure what to aligh it with.

Although the machine does now run OK it is a very short cycle at 20 mins and does not dry. Also not absolutely sure it is heating the water. Why no dry?

First time I ran it I opened the door a lot to check the arms were rotating. This seemed to upset the cycle a lot. I thought opening the door had no effect?

Had a lot of fat stuck in various places which may hav been the problem originally. Needed a hot wash with some cleaner.

[echase]

Re: Neff integrated dishwasher not washing properly

Where can I buy the little white plastic clips and stainless steel screws that hold the sump assembly onto the metal case? Mine only has 2 clips but there are 3 positions for them, so I assume one is lost.

Now run a 50C wash and it is not heating the water at all (or for such short periods that it has little effect) despite the element and the microswitch near to it having the correct continuity/resistance. Did not attempt to get to the drying stage. My possible diagnosis would be:-

The diverter disc, when in certain positions, completely blocks the water to both arms. Thus there is little/no flow though the heater in these positions. It would thus be dangerous to power the heater when flow is blocked as rapidly overheats. So the purpose of the cam and switch may be to detect whether the flow is blocked and disable the heater. If true I have the diverter disc in wrong poison. Problem is there are 3 more positions to try and it is a fairly long job to remove the base of machine to access the diverter. Is there an easier way to get the alignment right first time?

[Martin]

Re: Neff integrated dishwasher not washing properly

First off….use the Neff web site to see the parts you need although screws aren’t available as spare parts.

Secondly, never mess with diverters, it won’t work….trust me on that. Whilst you’re on the Neff web site, buy yourself a new heater box. And do take a close look at the main Control Unit aka PCB) as there may be a dry joint needing your attention.

[echase]

Re: Neff integrated dishwasher not washing properly

I think my original diagnosis was wrong. Diverter was not stuck between the 2 arms. I mistook the lack of spray arm going round as a sign that something was blocked or not pumping. But now I know there is a diverter device I realise that the lack of rotation was just because the water was currently going to the other arm. Have stripped and reassembled it and the arms are now working perfectly.

But apart from once having a 10 second burst near beginning of 35C cycle I have not had any water heating in many attempts with different types of cycles. This is worse than it was before.

I have checked all the heater circuit continuity of element, flow/pressure micro switch and even changed the heater relay on the PCB. Also checked for dry joints and found none. I later had spoofed the NTC temperature sensor to make the PCB think the water was cooler than it is. Still no heating.

I have tried the diverter gear in 3 of its 4 positions and it makes no or undetectable difference to the cycle of spray patterns.

So I don’t think it is the diverter or element that is faulty. What about one of:-

1) When checking the NTC I dropped it in water accidentally. The resulting water inside could have caused a partial short from the live terminals of the overheat stat in there to the NTC side which is at 1-2 volts. This could have damaged the input to the processor on the PCB so it can no longer measure temperature. It still does to work after drying it out.

2) Anther PCB fault that was originally causing faulty heating (hence the low wash performance) and now has stopped all heating. And/or it was only dirt build up that was the original problem and now I have killed it somehow.

With control PCBs being so expensive I’d rather get a new machine that buy a PCB.

[Martin]

Re: Neff integrated dishwasher not washing properly

echase wrote:With control PCBs being so expensive I’d rather get a new machine that buy a PCB.

I still maintain that the diverter unit is at fault and that the heater unit needs replacing. But now add into that mix the fact you’ve potentially shorted the PCB with the ‘unfortunate NTC incident’ then the overall expense renders any further repairs uneconomic at best, futile at worst. Buy yourself a new dishwasher in the January sales. 😀

[Author]

Posts