Neff S51M63X1GB constantly cutting out

[Martin]

Re: Neff S51M63X1GB constantly cutting out

Here is how it works….

[benwest]

Re: Neff S51M63X1GB constantly cutting out

thanks all. having done some more experimenting i’m pretty sure it’s not the door sensor.

i’ve figured out that the machine is consistently cutting out at the point it tries to drain itself (and fails). this happens 10 or so minutes into the first cycle after i have manually drained it. it spends those ten minutes taking in water, washing as normal, then pumping that water out into the matrix. then when it tries to drain this water to sewer it cuts out. any subsequent resets fail immediately because the matrix is full of water so the initial attempt to drain fails and the machine cuts out. it then needs manually draining to manage another 10 minutes.

the pump definitely runs (i can hear it, plus it manages to clear the main chamber to the matrix no problem). so the problem is somehow in dumping water from the matrix to the drain. the drain pipe is clear as far as i can tell. what else could i check?

[Martin]

Re: Neff S51M63X1GB constantly cutting out

benwest wrote:the drain pipe is clear as far as i can tell. what else could i check?

Let’s try to eliminate the drain from being a potential problem.

Has the drain hose been extended at all?
Does it connect to a drain spigot under the sink?
Is that spigot coupling free of fat build-up?

[benwest]

Re: Neff S51M63X1GB constantly cutting out

it hasn’t been extended. Yes it connects under the sink. I have fully removed the drain pipe and washed it through, and I’ve also done the same thing to the shorter pipe that connects the sump to the matrix. No blockages or gunk anywhere. also taken off and reinstalled the drainage pump to see if there was a hidden obstruction – nada.

(since doing this the drainage pipe is of course dry and the fault still occurs, so i reckon that rules out a blockage issue in the drain)

as i say there’s a whirring (motor/pump) sound accompanied by some clicking which lasts 20/30 seconds whenever the machine regains power then after that it cuts out completely and may not become responsive again for a fair while. i admit that i don’t know which pump i am hearing mind you. the drainage pump definitely spins because i can see it (and feel it), i wonder if the behaviour of successfully pumping to the matrix but failing to drain back out is consistent with a problem in the circulation pump instead?

cheers, ben

[Martin]

Re: Neff S51M63X1GB constantly cutting out

I think you’d best observe the fill/drain matrix (aka Heat Exchanger in Neff speak) to determine when the drain pump operates in relation to when it fills. Both are linked via the flow control device integral to the heat exchanger (impeller wheel operating a reed switch). After time those impeller wheels stick causing all sorts of program errors. The only cure is to replace the whole heat exchanger unit. Often too the little reed switch unit fails (very common).

Also it is worth noting that the drain pump is controlled by the main control board. It’s a DC motor that the board senses any power fluctuations (ie free flowing or blocked) and turns the pump on and off if it senses that it could be blocked.

Normally when any of the above fails or plays up the main board issues an error code. The fact that the board seemily shuts down and fires back up randomly without any such error codes is quite odd and not something I have come across before. 😕

[Author]

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