Siemens Slimline SF24200GB/01 intermittent rinse fill

[TimW]

We have an intermittent rinse filling problem with our Siemens slimline dishwasher SF24200GB/01. It always fills for the initial rinse and the main wash but often does not refill for subsequent rinses giving dirty glasses etc.

At the time, it was an entry level Siemens (Bosch) with mechanical programmer, no antiflood device, no lights.

The machine is about 5 years old, I think this problem might have existed for the past 2 years or more but is now very frequent, we had put the occasional poor rinse / wash performance down to bad loading (being a slimline, the top spinner does not get very close to the powder dispenser).

Last night I kept a close watch on the machine (well, there was nothing on TV!) and noted that the fill valve did not open when I expected it to (for the last 3 rinses). I manually added water with a jug each time and the result was perfectly clean glasses. After the program had finished, I turned the dial round to each of the ‘fill’ positions and the valve could be heard buzzing, and water was entering properly. The evening before, when I had not added water manually and had unrinsed glasses, I could not get the valve to open at any programmer position.

I have a theory that something is sensitive to temperature. Either the fill valve, the programmer, a float switch or an electronic control module works OK when cold, but once warmed up it stops working. By adding water manually, did I cool it down enough to make it work again?

Is it likely to be the fill valve, the programmer or is there an electronic control module that has become temperature sensitive?

I know I need to recreate the problem and put a voltmeter across the valve terminals, but it is VERY awkward to do this in our small kitchen and would like to know what else I should check while I have the machine out.

[Penguin45]

Re: Siemens Slimline SF24200GB/01 intermittent rinse fill

Cleaning out the corrugated hose in the front left corner will probably solve your problem.

Power off, though.

Regards,
Penguin45.

[TimW]

Re: Siemens Slimline SF24200GB/01 intermittent rinse fill

Thanks for the advice. 😀
I tried this last night and found that this hose had a tiny amount of sediment in it – no higher than the corrugations. I can see how this could become blocked and would prevent the unit from filling though.

Whilst I had the side off I checked the operation of the air pressure switch and it seemed to click on and off with the water more or less level with the top of the sump.
After being partially dismantled and reassembled, the machine worked perfectly this time. I cannot believe that it will continue this way 😕 but will add to this post if it does!

Do valves ever need replacing because they sometimes stick? or do they only ever need replacing when the coil burns out or they won’t shut off fully?
If it is not the valve, is it possible that the programmer is at fault?

[gegsy]

Re: Siemens Slimline SF24200GB/01 intermittent rinse fill

TimW wrote:
Do valves ever need replacing because they sometimes stick? or do they only ever need replacing when the coil burns out or they won’t shut off fully?

They can stick, usually by sedement jamming the gating.

If it is not the valve, is it possible that the programmer is at fault?

Programmers/timers very rarely go wrong to be honest.

Greg

[TimW]

Re: Siemens Slimline SF24200GB/01 intermittent rinse fill

I think I might have cured it 😀

When I had the side off, I took the air pressure switch assembly out and blew into it to check it worked. I noticed that there must only be a very small hole into the diaphragm chamber, presumably to slow down any air flow through it and ‘damp out’ any water level fluctuations. I blew and sucked a few times and noticed that it only needed a very slight pressure change but it did take a few seconds before enough air had moved to trigger the microswitch.

I am wondering whether I might have cleared a small blockage in the air pressure switch, because the machine has worked perfectly ever since 😀 It has only been 3 washes since but they have been absolutely perfect.

Thank you both very much for your contributions, without which I would have wasted a lot of time and still might not have fixed it.

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