Dishwasher not swishing: circulation pump gets no power (2nd attempt)

This letter never seems to have arrived in the group the first time -- trying again. Sorry if you have seen it twice now!
Hi,
I have a Beko "DE 2541 FX" slimline dishwasher that stopped working properly... just before Christmas.
When I press the button to start the cycle, the machine drains and then fills as normal and then -- instead of kicking into that rhythmic swishing sound -- it just sits there in dead silence. After 15 minutes it might fill again, and if left might fill yet again after another while. But it never kicks into wash mode. It does this even on the simple no-heat, pre-wash setting.
I checked the heater, it looks perfectly fine and is not open-circuit.
I checked the thermistor, fine, it correctly changes resistance when it's in hot water.
Everything looks pretty much perfect, after all it's only three years old.
The main circulation pump looks pristine, and so does its capacitor. But when I measured with a multi-meter across the terminals of the pump (insulated crocodile clips!), I discovered that at no time does it receive any voltage.
I decided to replace the controller card (only 30) and today I find it still has exactly the same problem with the new controller installed. Argh!
So what is the real culprit? Can anyone help? I know there is a circulation sensor, a thermistor, and various door safety and overfill doodads but I am not sure what exactly would cause this particular problem.
I would be grateful for anyone's experience and expertise: I don't want to be defeated by this thing!
With many thanks,
Sandy
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wibbled on Thursday 14 January 2010 22:20

<wild stabs in the dark>
I thought about the water level sensor (machine thinks there's no water) but as it apparently fills correctly, that suggests "a" level sensor is working. Could it be the main sensor has failed but a backup one (or a second sensing position on the main sensor) is preventing overfilling (don't know those machines, so I don't know if there is any validity in this idea).
Have you tested the level switch which might be in several forms to see if it's doing what you would expect?
Are there any relays on a supplimentary board or box somewhere?; thinking the controller is doing its stuff, but the relay that actually applies power to the pump has died?
--
Tim Watts

Icicles - nature's way of pinpointing all the leaks in your guttering...
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Tim W wrote:

My intuition says it is some sensor reading not working that is stalling the dishwasher programme.
The big problem with Beko is that there aren't any servicing manuals made available. (An operator at the UK Beko servicing place -- I think -- kindly let me understand that they *used to* make service manuals available, but no longer.) So I have only a very nebulous idea of what sensors and extra doodads the machine has, chiefly from disconnecting it, turning it on it's side and taking off the bottom plate.
I have "The Dishwasher Manual" by Graham Dixon (Haynes Publishing). It's not as helpfully written as I had hoped, but at least it encourages one to realize that, yes, all these machines are basically the same and fairly straightforward beasts.
However I have obtained the circuit diagram of my Beko dishwasher, the logic of which was designed by the Turkish company 'Arcelik'. I've scanned and uploaded the diagram here:
http://i49.tinypic.com/28r1thw.jpg
Unfortunately, I can only partly understand it. I think it doesn't help that at some stage, the character-encoding of the labels got screwed up. (O digital Tower of Babel that we live in!) I'm guessing that during design it was all Turkish, but now it's...not. Also, many of the symbols in the diagram, I don't recognize.
Counting the pins from left to right, here's what I *think* is attached to each:
pin 1 : main power button switch pin 2 : motor with capacitor? dunno. pin 3 : pump motor pin 4 : motor (without pump?? a "load"?) pin 5 : pump motor pins 8-9 : God knows what pin 11 : fuse, water-heater, normally-on microswitch pin 12 : a normally-off safety microswitch (?) pins 13-14: ??? pins 15-16: a normally-off safety microswitch (?) pins 17-18: ??? pins 19-21: Thermistor circuit
Mysteries: At the low left of the diagram, what is the symbol marked '6? In the middle of the diagram, is the thing labeled &2 a two way switch?
I think if I knew these things, it would help to connect (in my understanding) the diagram and the actual wires and devices I see dotted around the machine. Maybe also it will confirm your suspicions/theory about my fault?
I haven't been able to find this information about the circuit diagram anywhere on the web, which is why I've now written here with it, and put it up -- hopefully, someone who knows this stuff will be able to help fill it in, and so it'll be useful to other people with these kinds of problems in future...
... and of course, if it stops me having to wash up by hand every day, that would be WONDERFUL!!!
With many thanks (again),
Sandy
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Usenet wrote: > Is this how it's meant to feel, when you push the cooling blades around? The resistance is constant all the way around, so maybe this is normal... > > ...All advice welcome!
Dear Usenet,
The dishwasher is operating normally again!
I screwed the back plate back on, and connected the dishwasher up again to the water input and output. I ran it on the 15 minute pre-wash no heat cycle, fine. Then a 30 minute, 35 degree heater cycle with three changes of water, fine. The rotating arms took a while to clear themselves of little dried cloggy bits, but at the end they were going round like they always have. Swishing again!
What a journey I feel I've been, through! It so happened that there wasn't anything wrong with the dishwasher per se; the fault in my case was the slowly gunked-up water supply all along. But it has been incredibly worth it -- taking off the panels, seeing the workings, testing with the multimeter, and looking over the whole works. Now the dishwasher, washing machine, power wash, and eh even the power drill, and jigsaw, and anything else, are not mysterious black boxes anymore!
-
A note about Haynes' "The Dishwasher Manual" by Graham Dixon:
This book leaves much to be desired. It is not up to the standard of the world famous car manuals upon which Haynes' reputation rests. OK, the Haynes label gave me the initial encouragement to make me think I could repair my dishwasher, but beyond pictures of actual sub-components (most of which come from Dixon's earlier "The Washing Machine Manual"), the book hasn't been much help. More of a hindrance really. To be honest, the book seems not even half finished. The index of only several dozen entries doesn't fill a single page. Many of the diagrams have no labels and are not given a reference number. Repeated photographs of the same component, but with different comments, are seemingly there to bemuse the reader and help pad out the book. There are many infuriating chapters of one, or one and a half patronizing pages. The flow charts (speaking as a programmer myself) -- which are meant to help organize complexity -- are instead there to make the simple seem more complex, are all badly titled, unlabelled, completely moronic and waste yet more pages. And here's another what for: the chapter on pumps and motors is all about the goddamed potted physics, and the pros and cons of various approaches to motor design. No mention of how easily they can seize up, or how to go about unsticking them. There's a corporate engineering drawing of a "generic rotor" with cooling blades floating in space, but without anything else, no context! Where's the explanation on how to test if the motor's working, in situ? Or about taking care when manipulating big hose clips, or lubricating the inside lip of the hose with a smear of washing up liquid when putting it back on, of NOT using grease, which will corrode the rubber, or checking out the auricle's side exit first?
I hope someone in the near future writes a *real* Dishwasher Repair and Maintenance Manual. These are, after all, increasingly the times when we're going to badly need one.
With kind regards and best wishes to all,
Sandy
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Congrats. I fixed my DW a while ago. The float that checks the water level was caked in grease so it wasn't filling with enough water. I felt dead chuffed once it was working.
Just thought I'd mention that in uk.rec.cars.maintenance Haynes is sometimes referred to as "The Book of Lies" Their reputation has declined over the last few years.
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