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tony359

AEG okomix question

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Hi there,

first post here!

I've just received my new AEG Okomix washing machine, model L79485FL. Given the low quantity of water used by washers these days I thought a jet of water from the top would help keeping the laundry more soaked.

I have a question. The jet of water is not running all the time - it escapes me why but apparently that is normal. However, even when the jet is not running I can hear a humming noise which is clearly a pump running and I cannot understand what is that for! Okomix claims to mix the detergent better than other washers - to me it's a gimmick as I reckon a drum spinning in the water should be more than enough to dissolve the detergent!

Am I correct in saying that the humming noise I hear is the okomix pump getting water from the drum and injecting back into it where I can't see it? First, I'd like to know whether that is supposed to happen. Second, why not returning the 'mixed' water into the drum from the outlet at the top of the drum!

I'm basically trying to find out if the washer has a problem, being a discounted one for small cosmetic damage and it may have had some rough handling!

Thank you!

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Just to leave a reply for the future.

I have found that machine has three pumps inside. One is the usual drain pump. Then there is the 'okomix' pump which simply gets water from the bottom of the sump and inject it back to the *bottom* of the drum. It simply circulates the water.

The final one is the 'direct spray' pump which gets water from the bottom of the sump and injects it back through an orifice at the top of the rubber seal, pouring it on the laundry.

I have found that the latter only works during initial soaking and then when the temperature reaches the set point. The humming noise I could hear was indeed the Okomix pump, circulating water in the drum. I struggle to believe the Okomix can have any actual benefits - the drum is spinning in the water, wouldn't that be enough to mix the detergent??? Unless AEG noticed that powder detergents tend to sit at the bottom of the sump and dissolve more slowly.

So, happy days. The machine works perfectly fine to me.

Thanks

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Many thanks for the update Tony. It's much appreciated, and may help others in the future. I just checked out a video of one in action and it sounds like it makes the washing machine quite noisy. I have to say I share your scepticism.


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Thanks Andy

The noise is not so bad - even though the machine would be dead silent without it - and I'd like to think that if AEG installed an extra pump, the effect of which cannot be clearly seen by the customer, it may have some actual benefits on the laundry. I reckon that some powder may end up resting in the sump, away from the drum, and an extra pump may help dissolving it more quickly? But while the jet of laundry water on top is indeed - IMHO - a good idea, re-circulating the water at the bottom of the drum is questionable.

The animation in this video shows *exactly* how the system is made, it's very accurate, it depicts the components exactly where they are. The first pump shown is the 'okomix' - circulating water at the bottom. The second one is the 'direct spray' which sprays the water on top of the laundry. They work independently, with the okomix working most of the time and the direct spray only at the beginning and when temperature has been reached.

https://www.youtube.com/watch?v=K8XucaIsHOM

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Recirculating water to create a shower effect over the laundry is a long accepted device to reduce the amount of water needed. It's the shower verses bath argument. However, introducing a third pump is questionable for me. That's another mechanical device to potentially go faulty, leak or wear out. Washing machine manufacturers started to tackle the wasted detergent issue as long back as circa late 80s to 1990.

The issue is that when water is flushed into the detergent drawer from the start (as all washing machines used to do) then some detergent can end up in the sump hose that leads to the pump underneath the drum. Once there, this water is unlikely to circulate so this detergent is wasted. Recirculating this water as this system does will definitely address this potential flaw. However, for the last 20 to 30 years manufactures made a simple change which was supposed to fix this issue.

They simply fitted a small ball inside the sump hose. Then they made their wash cycles take in a pint or so of water from the opposite side of the dispenser drawer before sending water in to flush the detergent into the drum. This meant that the first flush of water had no detergent in and filled the sump hose. The water in the sump hose caused the small plastic ball to rise up and seal the entrance to the sump hose.

So when the detergent was flushed into the drum it all went into the drum. That has supposedly fixed the issue and in a very low tech inexpensive way. This Okomix system appears to be a more expensive and less reliable alternative. They may have come up with a better way but I'm not seeing it at the moment. Maybe it has some other advantage I'm not aware of..

To be fair I've seen those balls get covered in grease and gunge and stick to the drum seal. This prevented the machine from draining the water. However I wouldn't say that was a common problem. Also if doing a pre-wash then the system wouldn't work because detergent would be placed in both sides of the soap drawer. Again though I would think it's very rare for someone to use the pre-wash cycle any more.


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Very interesting, I didn't know about the ball. I agree the third pump seems to be an - expensive, prone to damage and overkilled - alternative solution for that indeed. This machine indeed loads water before loading the detergent, even though it flushes the 'stain additive' compartment when doing that. The machine does not have a separate way to fill just water.

Looking at the inside of the machine, you then realise that most of the parts are the same parts used by other machines (in this case Electrolux, Zanussi, AEG) and that after all... it's a metal drum spinning in a puddle of water! I hate marketing.

Out of curiosity, how does the machine weigh the laundry? And how does it understand if the laundry is not balanced when spinning? I could not see wires coming out of the shock absorbers, so it must be the motor sending some feedback to the electronics?

Observing how the machine loads the water makes me think that that could be the 'weighing' mechanism: if I load X amount of water and it's gone after Y seconds, then it must be at least Z grams of laundry - and that is done again till the water level does not decrease anymore. But during the spin there must be something else.

I have been looking for the service manual of this machine, I'd like to access the diagnostic menu - just for tinkering. I used the service menu of my Zanussi to sanitize the drum: I would heat the water to 90° and then I would run the 'tub leak' diagnostic, which spins the drum at 500rpm for a few seconds with the tub still full of water. Can you help me by any chance?

Thanks!

 

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Last year I was part of a small investigative team working with Which? Over 2 days we stripped down about 10 assorted brands of new washing machines. What we found was that they all use virtually the exact same parts. There is very little real difference in design and build quality between any of them. I was shocked to find that although Miele was far superior with its chassis, drum, bearings etc there were a surprising amount of parts that looked and felt little different to the other brands.

Yes, the only way they can realistically judge the weight of laundry and how well balanced it is is by monitoring the motor. The heavier the load the bigger the strain on the motor and presumably the more power it uses. Likewise, if the load is balanced well the motor will turn smoothly. If it's unbalanced it will turn and draw power unevenly.

The only manuals normally available are the instruction manuals. The technical manuals are usually closely guarded. I think Zanussi and AEG (same company) are the best at providing help to customers and sometimes have information on their web sites. I doubt if many others do though. The best way to look is via my Instruction manual downloads page. You should be able to at least find the manufacturer's web site and look from there.

 


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Very interesting, I thought so. (not only) Washing machines are a pack of marketing these days. I really wonder if they do some actual R&D and tests or whether all the gimmicks on those machines are made up from scratch to sell more. I guess that nowadays what matters is the software on those boards as, as you confirmed, most parts are identical between machines. But, again, I wonder if they actually do R&D and tailor the software to achieve the best possible result or just make sure the drum is spinning and create slightly different versions for different brands/models.

I shall research and find out how the board can get a feedback from the motor, that's quite interesting too. My AEG has a small inverter inside, maybe that gives more control power on the motor itself. But what about those machines with no inverter? I'll look that up!

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There's an explanation of how the motor speed is monitored on this article - Hoover Nextra error code 7 (tacho coil) It's done via the tacho coil which is mentioned in the article.


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I have found a patent from General Electric that allows the washer to monitor the current from the inverter - but that requires an inverter.

https://www.google.com/patents/US20130186199

I believe I've seen a tachometer on the back of the motor installed on AEG machines - it's probably easier to do and the same can be done on non-inverter machines.

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Strange that. I've not studied it in detail, but it seems to work just as I described they already do. Basically there is a magnet on the end of the motor's armature or rotor. Each revolution of the motor and its speed is monitored via a small tachometer coil mounted at the side of the magnet with by the module or pcb. 


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it also mentions monitoring the current of a phase through the inverter. Probably a more expensive way of doing so.

Quote

monitoring at least a single phase of motor current supplied to the motor while the wash tub rotates at the predetermined rotational speed during the data collection period;

monitoring the severity of tub strikes based at least in part on the single phase motor current; and

detecting an excessive out of balance condition based at least in part on the severity of the tub strikes.

2. The method of claim 1, wherein the single phase of motor current is supplied from an inverter coupled to the motor.

3. The method of claim 1, wherein monitoring at least a single phase of motor current comprises monitoring one or more phases of the motor current.

I've found the instructions for the diagnostic mode of my washer - which is basically the same on every Electrolux machine. Are you happy for me to post the link? It's in german :) (No, I don't know German but I can figure it out looking at the pictures!)

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Yes mate, thanks.


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http://www.waschmaschine-kaputt.com/

Click on Prüfprogramme and select AEG. You'll be presented with some instructions.

Basically - as with my old Zanussi and with any Electrolux - you enter the diagnostic mode which allows you to test individual components.

First 'programme' is to test all LEDs. Second is loading water from the pre-wash compartment. Third from the main wash compartment etc.

The one I like is the "tub leak" function. It loads water up to a minimum level (but you can increase it by loading the water using another programme first) and then spins to 250rpm for a few seconds. I use it to clean the tub, particularly useful if you first pre-heat the water at 90°C (function 6). It's a shame the machine does not come with a dedicated "tub clean" cycle, featuring the same thing.

The diagnostic menu is also useful to quickly rinse the machine after it's been off for a while. I'm doing the laundry every 7-10gg and sometimes the water at the bottom can stink (in that case you may need to run a hot cycle BTW). Rather than running a rinse programme - which takes time and, most importantly, will spread the stinky water around the tub - I load a little water and drain it several times using the diagnostic menu.

Anyway, I'm so far happy with my AEG. Only thing it seems not very good at very small loads - it loads too much water and clothes then float on it.

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