We have been having a problem with our Kenmore dryer. We dried a load of laundry. When I went to put another load of laundry in the dryer would not start. We replaced the thermal fuse and it dried another load. Again when tried to dry another load the fuse was blown again. Again we replaced the thermal fuse and the thermal cutout fuse kit. Again it dried a load but stopped working after that. The fuse was blown again, can find no othe problems. Heating element has 10ohm, no continuity to case. Can you help me?
Here are your parts
Parts for Kenmore Dryer 11063942100 - AppliancePartsPros.com
See the attachment for the tech sheet.
The most common cause of the thermal fuse blowing is a dirty vent system.
Check/clean the vent system.
Be sure that the exterior louvers open all the way.
Check the thermistor with a meter.
Check the exhaust temperatures.
I think the motor relay and heater relay are the same, but I would double check this. If they are I would swap them. Could be the heater relay is sticking closed.
63942100.pdf (290.6 KB)
Thank you for the valuable information. I ran through the tech test and all components seem normal. So I replaced the thermal fuse and the heat relay. The dryer then worked for about 30 minutes. The dryer got very hot as well as the clothes that were inside. I cannot see any problem with the heat element. So I am kind of at a loss again. Any suggestions?
Have you checked the heating element with a meter?
Unplug the unit and both wires from the heating element.
Measure across the element should be around 8 to 12 ohms.
Then check from each side of the element to it,s case, both should be infinite ohms.
If not you have a grounded element and it should be replaced.
Check that the blower wheel is properly attached to the motor armature.
Sometimes they can strip out so that they will turn but are slipping on the shaft.
Thank you once again. The heating element was 10 ohm and not grounded to case. The blower wheel is attached. Today I replaced the thermal fuse (again) and the thermostat. Same thing happens (runs about 30 minutes and fuse burns). Any suggestions?
[COLOR=“Blue”]Today I replaced the thermal fuse (again) and the thermostat.[/COLOR]
Which thermostat?
Did you check the thermistor resistance?
Did you check the exhaust temperature?
Does changing the temperature setting also change the exhaust temperature?
Two things can cause the fuse to blow either an air flow problem or the heater is not being regulated.
The thermostat that we replaced is the thermal fuse.
We did check the thermistors resistance.
We checked the exhaust temperature and it did not change with the switching of the heat settings. The dryer runs hot even on air fluff.
I changed the heat relay and installed a new temp setting control. Same problem.
Since the air flow seems to be working fine, what is the part that regulates the heat? Thanks
The control board regulates the heat.
It uses the thermistor resistance to tell it what the actual temperature is and then turns the heater relay on/off as needed.
There are two types of air flow problems that can cause overheating. One of them was mentioned by Denman: obstruction. (Typically by lint buildup obstructing the lint trap or exhaust ducts or exhaust vent. Possibly by lint blocking the air intake holes at the back of the drum. Possibly by something covering the air intake vent at the back of the dryer.)
[COLOR=Blue]The other type of air flow problem is a leaking seal.[/COLOR] A leaky seal creates an undesirable alternate path that allows a portion of the heated air to flow OUTSIDE the drum. The heated air that flows outside the drum will heat up the dryer cabinet and may blow the thermal fuse.
So I recommend you inspect the seal(s). According to the list of parts for the Kenmore dryer, the seal is a circular strip of felt at the front of the drum, where the front of the drum mates with the inside of the dryer’s front panel.
Your dryer may also have a seal at the back, but my intuition is that a leak at the back is less of a problem than a leak at the front since a leak at the back involves only a minimal length air path outside the drum. If the seal at the front is okay, check the seal at the back.
There may be an additional seal lining the dryer door, which is easy to examine. I think the door seal is less likely to undergo significant wear and tear than the seals around which the drum rotates, but if it’s bad it would allow air to be sucked in at the door, which would reduce the amount of hot air sucked into the back of the drum, which could cause the hot air at the back to overheat the dryer cabinet.
By the way, my observations of temperatures inside my dryer taught me that neither the control thermostat (which senses the exhaust temperature) nor the dryer’s temperature control dial (high heat, medium heat, low heat) are designed to have any effect except near the end of the cycle, when little moisture remains in the clothes. Until then, evaporating moisture causes the clothes and the exhaust to remain relatively cool. (If you don’t understand this, try googling “evaporative cooling.”) So, for most of the drying cycle, the cool exhaust causes the control thermostat to stay closed, which causes the heating coil to stay fully on (even when the dial is set to low heat) until the clothes are nearly dry. (This applies only to the high heat, medium heat and low heat settings, not to the “no heat” setting, of course.) The heating coil is designed to always be either fully on or fully off; the low heat setting causes the heat to turn off more frequently than the medium or high settings, but only when little moisture remains in the clothes, which is when heat-sensitive clothes might get too hot.
[COLOR=Blue]That means the control thermostat and the temperature control dial are irrelevant to a thermal fuse blowing problem.[/COLOR] If your heat-sensitive clothes get damaged when the dryer is set to low heat, that’s a situation in which the control thermostat or control dial may be relevant. (If the dryer heats when the dryer is set to “no heat” that’s another situation when the control dial–but not the control thermostat–may be relevant.)
I guess I disagree with some of what Denman suggested you check. Your dryer is overheating long before the clothes are nearly dry. I think the dryer shouldn’t overheat even if thermostats or relays are stuck closed, because during normal operation the heating coil is designed to be fully on anyway (until the clothes are nearly dry). For the same reason, the exhaust temperature is irrelevant since it should be too cool to open the control thermostat until the clothes are nearly dry. And changing from high heat to low heat won’t affect the heat or the exhaust temperature until the clothes are nearly dry. (If I’m mistaken about any of these things, I hope Denman will explain why.) I agree with Denman that air obstruction is the first thing to check since it’s the most typical cause. And I agree that a partially shorted heating coil might be the problem, since the full voltage would travel through less resistance, causing greater current than designed, and the heat produced by a resistor is proportional to the product of voltage and current.
If you want to monitor temperature, the Uni-T UT200 multimeter sells for about $15 at Amazon. (I bought one recently, so now I have two multimeters and can observe two temperatures simultaneously. Observing temperatures at both fuse and high limit thermostat helped my understanding of my dryer’s operation.) If you don’t already have a multimeter with a temperature probe, it might pay for itself quickly by letting you protect your dryer’s fuse until you’ve fixed the overheating problem; you could switch the dryer’s temperature control dial to “no heat” each time the temperature at the fuse approaches the fuse’s blowing temperature.
Thank you for all of your wonderful help. We found the control board to be defective.
[quote=APPPROLSP1;868008]We found the control board to be defective.[/quote]
Glad you solved your problem!
I should have asked this earlier, since you said your dryer’s thermal fuse would blow after about 30 minutes: How dry did the loads get in 30 minutes? For the moment I’ll assume the loads had completely dried, since you wrote that you discovered the dryer wasn’t working when you tried to do the next load.
Once the load becomes dry or nearly dry, evaporative cooling stops cooling the load & drum & exhaust. At that point, the heat needs to be regulated. (Since the exhaust gets warmer then, the exhaust temperature can serve as the input signal to the regulation circuitry.) Overheating that occurs after the clothes are dry or nearly dry is likely due to an issue with the heat regulation circuitry. This appears to have been the case with your dryer since replacing the control board fixed it.
The regulation circuitry depends on the dryer model. My 17 years old dryer uses a thermostat (called the “control thermostat” or “cycling thermostat” to distinguish it from two other thermostats in the dryer) located in the exhaust flow, and a fabric temperature selection switch & network of resistors to set the bias temperature of the control thermostat. Newer higher tech models use a thermistor (a temperature-sensitive variable resistor) instead of a thermostat, plus other control circuitry, for more precise control over the temperature, and may also have a moisture sensing circuit for additional control.
When I monitor my dryer’s temperature, I see the control thermostat begin to regulate the heat after about 45 minutes, when the load has become nearly dry. If your loads are nearly dry after only 30 minutes, I’m envious!
Rereading your earlier messages, I see that your dryer would heat up even with the fabric temperature control set to air fluff (which is supposed to turn off the heat). That was a major clue… sorry I missed it. (On my old dryer, that symptom would imply a short circuit somewhere in or close to the fabric temperature switch, because the switch in air fluff position is supposed to be open.)