Thread Number: 23353
Automatic Water Level Control - How does it work? 		[Down to Last]

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Post# 364048   7/15/2009 at 01:05 (5,399 days old) by washlogic (virginia)        

Just purchased a Maytag (Whirlpool) top-loader washer, model MVWC6ESWW. Before buying it, I read the reviews of people who had purchased it on various merchant's sites (Lowes, Home Depot, Sears). It claims that its efficiency is due to the Automatic Water Level Control. Although it got decent reviews for efficiency (it is energy star rated) most people did not like the fact that you cannot control the water level. If you open the washer after the washer has filled, the washer is programmed to fill water at the highest level. I also noticed that when starting the washer, the machine begins to fill, then agitates then stops until the water is at the perfect level and agitation begins again. This mystifies me on how it knows when to add enough water or how much clothing I have put into the tub.

Does anyone here know how the Auto Water Level mehanism works?




Post# 364076 , Reply# 1   7/15/2009 at 07:30 (5,399 days old) by toggleswitch2 ()        

I'd like to know myself.

If I had to guess, I'd say sensors measusre drag on the motor during agitation by way of speed or current /amperage draw.
Then water is simply added until drag is reduced to the "proper" range/level.

Post# 364078 , Reply# 2   7/15/2009 at 07:40 (5,399 days old) by ronhic (Canberra, Australia)        

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I remember reading something about 'sensing' years ago with Fisher & Paykel. From what I understand the electronics detect/analyse the 'slip' (or drag as the case may be) of the clothes through the water.

So Toggles is correct.

Front load machines at their most basic use absorbancy in combination with a pressure switch. So they fill until the switch registers 'enough' and start to tumble. As the load absorbs more, the switch triggers again as the water level drops. More water is added, the switch triggers 'enough'...so on until it doesn't happen any more. Voila.

Post# 364086 , Reply# 3   7/15/2009 at 08:15 (5,399 days old) by favorit ()        

i guess that also some FL have the current/amperage draw thing

for instance,in case of a heavy load, Mieles use hi water levels while rinsing and have a different pattern/cadence while washing compared to half loads.
I guess the board sums up the info from the water flow-meter with those from the dynamo on the motor shaft sensing the current draw.

I also notice that the spin after the wash bath is far more accurate than other ones. It ramps up very very slowly to prevent oversudsing and creases

Post# 364116 , Reply# 4   7/15/2009 at 09:45 (5,399 days old) by cornutt (Huntsville, AL USA)        

There's different mechanisms on different models. I believe that at least some of the Whirlpool/Kenmore Oasis models use a floating basket mechanism. The GE Harmony applies impulses to the wash plate with the dry load (prior to filling) and measures how long it takes for the wash plate to stop moving. Then it does a couple of twists and turns of the basket while it is filling and uses that to fine tune. Then, at the beginning of the wash cycle, it does the wash plate impulse thing again. It's not uncommon for it to pause and add more water at least once; I've seen it do that as many as three times. It notes the final fill level and uses that same fill level for all subsequent fills during the cycle.



Post# 364122 , Reply# 5   7/15/2009 at 09:55 (5,399 days old) by logixx (Germany)        

logixx's profile picture
How Auto Load Detection works, from ServiceMatters.com

Post# 364258 , Reply# 6   7/15/2009 at 16:51 (5,398 days old) by washlogic (virginia)        

Logixx, I appreciate you finding this information. I have looked on line previously and were not able to find anything.

Whirpool calls it "auto load sensing" or something like that.

This is pretty interesting stuff. My washer does have that same "Softener Added" Switch on the panel, which the owner's manual did not give a heck of lot of information for it.

I just thought it was a dummy control to make the washer look more sophisticated to potential buyers. Who knew??

Thanks again!

Post# 364324 , Reply# 7   7/15/2009 at 21:40 (5,398 days old) by brisnat81 (Brisbane Australia)        

The Miele dont use current draw to calculate water levels.

They way that a Miele friend has explained it, is as follows:

Wash levels maintain the water level at a preset level, as the load absorbs water, it keeps topping up to the preset.

For rinses, the machine fills to the preset level and continues this process until the water level has stabilised, as per the wash. Then the machine calculates the temperature rise, based on the inlet temp and the temp of the clothes. The theory being that the quicker and higher the temp rise, the more water in the fabric and therefore the more water that is required for dilution. Then the machine adds additional water on top of the preset limit to take into account the absorbancy of the clothes.

It measures the resistance on the motor to calculate the wash rhythm and the spin profiles.


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