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Sherlock Ohms

Case of the Tricky Water Pressure Switch

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Ann R. Thryft
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Blogger
You can keep the switch, Bob
Ann R. Thryft   11/9/2011 8:18:19 PM
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What seemed to be the same problem happened to our 10-year-old GE washer last year. I'm really glad in our case it turned out to be just the switch!

Dangela
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Bronze
clothes or no clothes
Dangela   11/10/2011 9:23:49 AM
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I would thinnk the weight of the tub would depend solely on the level of the water, not whether there were clothes in it or not.

gafisher
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Gold
Re: clothes or no clothes
gafisher   11/10/2011 10:18:21 AM
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Wet clothes would put additional stress on the agitator regardless of water level.  It's not a weight issue per se, though it came across as that; rather, it's a loading (or drag) issue.

JRThro
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Iron
Re: clothes or no clothes
JRThro   11/10/2011 4:29:44 PM
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Whether or not there are clothes in the water will matter unless the density of clothing and the density of water are the same.

Dangela
User Rank
Bronze
dryers are much easier to work on
Dangela   11/10/2011 10:21:31 AM
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When my electric dryer wouldn't heat up I would have bet money it was because the heating element went bad. It took me about an hour to tear it all apart to get to where I could ohm out the element. It tested good. I took the inpection panel off from behind the controls in a matter of seconds to see the control had melted.

Dave Palmer
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Platinum
Validation and testing
Dave Palmer   11/10/2011 12:14:02 PM
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This is a good example of the pitfalls of trying to validate a design solution with a test which doesn't adequately represent real-world conditions.  With a small amount of water and no clothes, replacing the pressure switch appeared to work.  It only became apparent that the pressure switch wasn't the problem when you tried to use the washing machine to actually wash clothes! Let those who are tasked with developing test and validation programs beware.

Tim
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Platinum
Washers
Tim   11/10/2011 7:25:04 PM
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Washers do see a lot of force and friction during the normal operation.  It is probably one of the hardest working pieces of equipment in a house.  That may be the main reason that there are so many articles in Sherlock Ohms about washer failures.

thehobe
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Iron
Re: Washers
thehobe   11/11/2011 10:50:24 PM
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We used a Maytag for about 7 years before the unit would not work. It seems the wiring to one of the pc boards was very loose so I recconnected the wires but the washer would still not wash. I replaced all of the power transistors on the motor control board to no avail. I finally purchased a combination motor and motor control board from Ebay, installed it and it has been working fine ever since. I was glad that I did not have to "junk" the entire unit causing global waste instead of repairing the washing machine. The loose wires appeared to be some kind of tachometer feedback to the motor control board. The loose wires may have taken out the motor microcontroller but I was not sure.

Rob Spiegel
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Blogger
Re: Washers
Rob Spiegel   11/14/2011 11:34:32 PM
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Yes, Tim, there are plenty of washer stories in both the Sherlock and Monkey blogs, but most of the posts find difficulty with the control panels rather than the mechanical operation of the washer. Even with the wear and tear, washers are remarkably durable. It's the relatively new electronics that seem to create most of the problems.

dutchman
User Rank
Iron
Re: Washers - relatively new electronics problems
dutchman   11/17/2011 11:12:29 AM
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I womder if tin whisker growth have anything to do with it. (See: http://www.eetimes.com/design/military-aerospace-design/4230652/Understanding-and-mitigating-tin-whiskers?cid=NL_MilAero&Ecosystem=military-aerospace-design )


Rob Spiegel
User Rank
Blogger
Re: Washers - relatively new electronics problems
Rob Spiegel   11/17/2011 2:29:52 PM
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That's a very good question, dutchman. I've heard tons about contrl panels failing in equipment such as washers, dishwashers and refrigerators, but I haven't heard much about what caused the failures. Users shell out the bucks, replace the control panels and move on.

Maybe it is tin whiskers.

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