June 9th, 2005, 08:19 PM
I read the thread on the Elite dryer - dealing with thermal fuse, thermistor, thermal cut off and thermostat.
Given my current problem - I'm a bit confused about what they all do - and how I can tell which part is faulty. I'm not sure what to test for - if the part is faulty vs. when it is working fine. Can anyone help?
The dryer runs - except there's NO HEAT coming out. So - I took the front bottom panel off and cleaned up all the lint. And there was a lot of dust/lint as this has never been done before - had the dryer for about 4 years.
So according to the diagram:
Diagram LINK > Diagram here
#42 is the thermistor
#59 - thermal fuse
#47 - thermal cutoff
#48 - thermostat
I disconnected each of these parts and tested them with an ohm meter.
#42 - thermistor reads 9k ohms.
#59 - thermal fuse reads 0 (zero) ohms - basically continuity.
#47 (thermal cutoff) and #48 (thermostat) also read 0 (zero) ohms.
I am guessing that #59, 47 and 48 reading zero resistance is "normal" and so the parts are working fine.
The thermistor (part#42) is suspicious. Not knowing what it (#42) really should read - I took a chance and re-installed all the parts.
I reconnected the power - and started the dryer. Now - It ran fine - there WAS heat. The heating coil was glowing red hot on all the different heat setting.
Then - at one point - I stopped the dryer and restarted it again. The problem re-appeared. The dryer drummer turned (just like all the other times) BUT NO HEAT again! The heat problem comes and goes.
Could it be the thermistor (part #42)? It is reading 9k-ohms (with the leads disconnected). What is the reading expected to be IF it is working fine?
I suspect it's the thermistor - because I'm pretty sure the other 3 parts are working fine.
Any ideas would be appreciated.
- Modified long link
June 9th, 2005, 11:03 PM
Loooks like the matching dryer to the Catalyst washer :shock:
220 Volt electric dryer - the element will naturally cycle on and off. You may be intermittently losing one "leg" of your 220 supply. There is a "tech sheet" inside the console of your dryer which gives details on how to test the thermistor.
Some good info on how to take apart and check here.
June 10th, 2005, 06:46 AM
Thanks Mad Mac - the link was very useful.
I was looking for the "tech sheet" and did not think tolook for it in the console. I'll open that up tonight - hopefully it's there.
BTW - is there a "basic" explanation of how the thermistor works.
Like -what's its purpose/function? I readsomewhere - that it's supposed to"sense" the temperature and report its reading back to the controls. The control then adjusts the heating element (or something). Is my understand on the right track?
Also - when I took a reading of the thermistor (with both wires disconnected from it) - it gave a reading of 9k ohms. Is this a normal reading at room temp? If this is an indication of a faulty thermistor - then I buy a new one this afternoon before going home (from work).
June 10th, 2005, 11:09 AM
Basically, its a resistor whose resistance varies with temperature. The microprocessor in your dryer sees the change of resistance and turns the heat on/off as necessary. The thinking is that the conventional thermostat has two positions (closed and open) whereas the thermistor varies, giving a more accurate "picture" of what's actually going on.
I don't recall what reading you should get at room temp, the tech sheet will tell you more about that.
June 10th, 2005, 04:03 PM
I doubt it. If the thermister had failed, an E1 or E2 error message would usually display on the control panel.
Could it be the thermistor
When isolated from the circuit, @ 21°C (~70°F) 11.9 ohms.
It is reading 9k-ohms (with the leads disconnected). What is the reading expected to be IF it is working fine?
There are more in the heater circuit than just just those. You can read about the others at the following link although it doesn't show any type of electronic control which your dryer uses, which is a possibility as well. The timer contact shown at the linj would be equivalent to the heater relay of the control board (see the 2nd link below) on your dryer model.
I'm pretty sure the other 3 parts are working fine.
LINK > Can anybody tell me the most likely scenarios for lack of heat in an electric dryer?
LINK > Kenmore 110.60092991 Control Board part # 3978696
The Appliance Information Site
June 10th, 2005, 07:00 PM
OK- so here's an update...
Dan O. - you're were absolutely right - it's not a faulty thermistor problem. Your links were very useful - thanks.
I found the technical data sheet behind the console and the thermistor resistance was up to spec.There's a table of resistance at different temperatures - so that was a useful exercise.
I followed the troubleshooting steps - and came to the conclusion that the root cause ofmy problem is the "Panel Console/Key Switch/Touchpad Assembly".
To test this - I followed the procedure: I removed the P3 and P4 connectors and measured the resistancebetween thevarious pins of the cable ribbon connector (P3 and P4). There was an open circuit (infinite resistance) when the various buttons (cotton, normal, permanent press, etc) were pushed. It's supposed to read 2-4M ohms when it's working properly.
Then - I called Sears 1-800 in Canada and HOLY SMOKES - the replacement part costs $370 !! :shock: Like I thought - it might be 50-60 bucks - maybe 100$ max - BUT $370 !?? We paid $800cdn for the dryer 5 years ago.:X:shock:
Before I dish out that kinda of money - I think I'll go back into the basement and double check my testing!! Maybe I missed something.....
BTW - when I re-assemble all the parts - including re-installing the original thermistor - the dryerworked again. There was heat. Then - I turned it on/off a few times- testing the different setting (cotton, perm press, etc) - the heater coil stoppingworking again. So - it's definitely an intermittent problem. (I also checked the circuit breakers at the panel - in case one of the two breakers had tripped - but they were OK).
So -can it be possible that the console panel/touch pad assembly be defective after only 5 years of moderate use? (It seems a bit soon - I kinda expected it to lastmuch longer.) It just seems a bit premature - anyone with experience on this?
Also - do they have places that sell "used" appliance parts ?
June 12th, 2005, 01:28 PM
Certainly, s**t happens.
So - can it be possible that the console panel/touch pad assembly be defective after only 5 years of moderate use?
I however have by doubts a problem in the touch pad alone would cause "intermittent heating". That is something more likely to be caused by an electrical or electronic component like the control itself rather than just the switches which tell the electronic control what to do like the touch pad does. A problem in the keypad would usually just stop those functions from being selected in the first place.
Not usually but you may find a used appliance dealer with piles of stripped components 'out back'. I very much doubt that they're bother hanging on to something like a control panel where just about every single model ever produced would use a different one. They're more interested in common components, ones which can be used on any (or at least very many) different machines.
Also - do they have places that sell "used" appliance parts ?
The Appliance Information Site
June 12th, 2005, 03:11 PM
A couple of things happened since my last post:
1) I've calmed down a bit ... (over the price of the console touch pad.)
2) I've called around Ottawa for new and used console touch pads and it seems that they were really "surprised" to hear thatminewas defective already after 5 yrs. The used parts guy actual never received a call for one and the local CAMCO partsguy also said he doubted my problem is caused by a faulty console pad. So - I guess everyone is pretty much in sync - that it would be strange to have this part go bad so soon.
When I looked at it closely - thereseems to be very few components that could go bad. I kinda agree with the gut feel that it could be the control board with all the ICs and components. But - I wouldn't be able to test that - I guess - too complicated!
Back to the touch pad / console for a moment - there's a section in the tech sheet (p.7) that describes how to test the functions of this part. For example - it says to measure the "resistance" between cable P3-11 (+ lead) and P3-14 (- lead) and expect to get a reading of 2M - 4M ohm. It says to make sure the correct polarity is used. When I tested this - I got a reading of high/infinite resistance. So - this indicates that - that "COTTON- HIGH heat" button is bad. HOWEVER - IF I interchange the polarity - ie.P3-11 (- lead) and P3-14 (+ lead) - I got a reading of 4.9M ohm. So - still out of spec - but at least it's closer to the expected reading. Same for all the other buttons (cotton, normal, permanent press, etc). I don;t know what this means - except to think that the touch pad was faulty.... My neighbor said that the spec sheet could be wrong too. Who knows?...:?
(Sorry for all the detail - but maybe someone else can benefit from this exerience.)
Anyhow - I finally gave up - and re-assembled all the original parts. The heater coil still comes on intermittently, it doesn;t seem to matter what "state" the machine is at.
For instance -
1)With the dryer completely cool - I press the high heat/cotton button - then start. RESULT: The dryer starts - the heating coil lights up. Then - after maybe 2 mins - the heater coil shuts off. I stop the dryer - then - immediately start it again. RESULT: The heater coil works again - then shuts off after 30 sec.
2)With the dryer completely cool - I press the high heat/cotton button - then start. RESULT: The dryer starts - BUT the heating coil doesn't work - NO heat.
The machine seems "possessed" or something....?
Is there a part or component - that could be "flaky" - passes the tests but then fails under operation?
June 14th, 2005, 07:05 AM
Well .... the dryer managed to dry 3 loads so for. Heater coil comes on and stays on for the duration of the cycle.
( I guess testing the dryer with an empty load - may have turned off the heater coils after 2 min. - I guess ? - that's the proper way it's supposed to work? )
Whatever the problem was - it's (somehow) been fixed - at least for now.
Thanks for all your feedback Dan O. and Mad Mac. You've probably help save me a few hundred bucks. Much obliged.
BTW - since the console key pad seems to work now - I don;t understand why it failed the testing - according to the procedures in the tech sheet. Oh - well....
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