The clothes in our Kenmore dryer became so hot during a load one day that we thought they were going to catch fire. I ran the dryer and watched the heater box. The heater element was glowing red hot and did not respond to box temperature or heat setting. Naturally, my first thought was that either the temperature sensor had blown or the high temperature cutoff switch was bad.
I pulled the dryer out from the wall and took the back off to access the controls. While running the dryer, I was able to determine that the switches were operating correctly, but the heater element was still glowing red. Next, I pulled the cover off of the heater element compartment and ran the dryer again. To my amazement, half of the heater element was turning on and off properly, but the other half was full on all the time.
The heater was coiled nichrome wire that was mounted on insulating porcelain standoffs. There were six lengths of the heater wire, about 18 inches long with an insulator at the ends only where the heater turned. After many years of use, and many heat cycles, the middle loop had fatigued and was curved toward the firewall between the heater compartment and the clothes compartment. Of course, this baffle was metal, connected to the rest of the dryer frame, and therefore, grounded.
The thermostat and over-temperature switches were both on the same, single side of the 220V line. Consequently, when the center of the element contacted the ground there was approximately 110V across that portion of the element all the time. Hence, there was always lots of heat being produced whenever the dryer was on, with no control. Fortunately, there was no power applied when the dryer was off, otherwise we would have been paying an excessive electric bill until it was repaired. We also would have been in danger of a fire.
Kenmore should have designed the heater layout with more support at closer intervals than 18 inches, especially since this was in an appliance that was constantly subjected to vibration and the thermal cycles that would tend to flex the nichrome wire.
This entry was submitted by Thomas R. Clem Sr. and edited by Rob Spiegel.
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One thing that I must not have made adequately clear is that this occured over 20 years ago to a dryer that was at least 10 years old, as best I can recall at my advanced age. We have had many Kenmore appliances and for the most part they were very well built and reliable. This situation was an exception, but still an example of poor design.
Good to hear that was an old model. I am about to purchase a new dryer. I actually hate buying new appliances all together. It seems every replacement lasts less and less than the one before it. Whether it be poor design or build quality, or that they just have more to go wrong with them.
1) The FIRST thing you must recognize is that KENMORE is a SEARS, ROEBUCK brand. They do not manufacture appliances. For the past 40 + (maybe 50+) years your good friends @ WHIRLPOOL have been the manufacturer of the KENMORE washers & dryers & other large appliances. So, it is more fitting in light of the many negative posts here to blame the WHIRLPOOL CORP. for shoddy engineering / design.
2) With the increased complexity and feature lists of modern appliances, it seems entirely reasonable that a particular model might have been designed w/ effective & high quality sensors to start, BUT when the "value engineering" group got together w/ the "bean counters", many of these sensors got "dumbed-down" in quality, ultimately leading to premature failures. It would NOT have surprised me to be able to view the ORIGINAL design for the heating elements section and notice that there were several more ceramic standoffs in place, BUT ........
3) We had a HAMILTON (natural) gas dryer along side a 1950s era LADY KENMORE washer, which served the needs of the family for several decades WITHOUT one hint of trouble. The end came eventually for both but it was not after they racked up countless thousands of cycles. The HAMILTON dryer failed for a part in the gas delivery system, but since HAMILTON had gone out of business, there were no replacement parts available. The KENMORE washer had a totally fatigued transmission. Although replacement parts were available, we splurged on an updated model.
Since this is not a common problem, I suspect an isolates assembly error or a one time faulty part. So we probably have just one Monday morning monkey.
I doubt that there is a "wealth of engineering knowledge" behind any of these products anymore. Most of those with that wealth of knowledge have been retired (if they are lucky), downsized, outsourced, or just plain let go. That's the way it is with the employer I retired from with 30+ years of design experience.
Both GM and Chrysler (disclaimer: I was an engineer at GM in the '80s and '90s) are now desperately trying to hire skilled engineers to repalce the ones they let go over the past 5 years. They can't find people with the skills they need, at the wages they are willing to pay.
Actually, open nichrome heating elements, with their superior heat transfer characteristics, have been used with very few problems since the electric dryer was first invented. Before blaming the engineering (I have seen these machines in use for more than 50 years and still going strong), ask yourself about your maintenance habits. Clothes dryers, both gas and electric, should be cleaned of lint at least once a year. The residue of modern synthetic fabric materials that escapes around seals and clogged lint filters is much more flammable than that of cotton or wool. In reality, the cause of the problem that you describe is almost always indicative of a long-term clogged vent or lint filter.
"In reality, the cause of the problem that you describe is almost always indicative of a long-term clogged vent or lint filter."
Very true. Don't forget to inspect the vent line for obstructions when you relocate to a new home/apartment.
Upon doing my first load of laundry in an apartment which I had just moved into, I had a brand new electric dryer run very hot (saw red coming from the coils underneath).
Upon inspection I found wadded up plastic groacery bags shoved down the vent tube to stop cold air entry during the winter.
Sad thing was that the apartment had been the complex's office until a new office/pool building was built. That showed how much pre-inspection was NOT done by the "maintenance" person. Had this been any other apartment with the same issue and a less than aware tenant, the issue probably would have caused a fire for the entire building.
Did the issue do damage to the dryer? I don't know. Since the washer/dryer was provided by the management in the rent package, I did not really care.
The dryer still worked 3 years later when I sold the units.(This was after the management removed the washer/dryer in rent provision package, I had moved to a different building and apartment unit [moving the washer and dryer under the old lease terms], and finally the complex was sold and changed management firing all the prior management maintenance/office personnel. At my final checkout inspection from the complex, the new manager said that if I didn't remove the units I would be charged a clean out fee. Of course I said "Sorry, my friend was late to pick the washer/dryer up with his pickup." The units were removed post haste and I received my entire deposit back... )
I have seen nichrome coils break in an electric-range oven and in a toaster. Failures happen.
I'd be surprised if the dryer didn't include thermal cut-off sensors. A company called Klixon makes a wide range of accurate thermal switches and I've seen them in dryers. When the temp gets above the switch's limit, power shuts off. The next time you open a dryer for repairs--usually a broken belt--look for temperature sensors on the exhaust tube and on the dryer compartment. They should be there.
Haven't you people heard of a ground fault circuit interrupter? If you had one in your main fuse box (mandatory in some enlightened countries) it would have cut the power as soon as the fault occured. (it trips when there is an imbalance in the phase and neutral currents, which would happen if current flows to ground).
Good points, LloydP. In 2008, the automation industry was wringing its hands over the boomers retiring. Then the crash happened. 401s tanked and thousands of engineers put off retirement. But it has got to be a problem. I was talking to a vendor who noted that the last engineer who knew how to shut down a utility plant had retired. They had to hire the vendor to teach the control engineers how to shut down the plant.
When your lab is only one scope, one meter, and one homebrew function generator and power supply, the scope is stage center. But this one wasn't working right.
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