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What is causing the thermal cutoff on my dryer to blow?

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November 29, 2019, 09:34 PM
thumperfbc
What is causing the thermal cutoff on my dryer to blow?
Whirlpool LER5636EQ3 electric dryer

Maybe 6-8 weeks ago my wife reported the dryer wasn’t drying clothes very well. So I investigated and found that it seemed to work normally except for the lack of heat. Simple google searching revealed how to trouble shoot it and I easily found the thermal cut off was non-functional. I got the part from a local parts place and all was well.

Well, it went out again yesterday. Same symptom of no heat but otherwise normal operation. More reading indicated I should check for flow restrictions but I found none.

I removed screws from the exhaust duct in the dryer enough to get my hand in there. All clear. Flex hose was not kinked and devoid of fluff. There was definite flow exiting the duct outside our home but I cleaned out the entire ducting anyway with one of those duct brushes on a fiberglass pole (very little came out). Lint filter is cleaned regularly.

Buttoned it all up with a new cutoff again and it is working fine.

But why did it blow? Should I replace all the thermal components (such as the fuse and thermostats?)

Thanks!
November 29, 2019, 09:40 PM
PowerSurge
Check that the thermistor is still working and that it isn’t covered in lint.


———————————————
The fool hath said in his heart, There is no God. Psalm 14:1
November 29, 2019, 09:47 PM
Aeteocles
Lint trap change regularly, or changed *every* time?
November 29, 2019, 09:53 PM
P250UA5
Our Whirlpool Cabrio does similar from time to time & has the check vent light on.

Vent is clear & lintel screen is cleared religiously before starting the dryer.

Will have to find a diagram to check the thermistor. Same issue on our hot tub heater.




The Enemy's gate is down.
November 29, 2019, 09:56 PM
cparktd
I had one do very similar. An ~18 yr old Maytag. The hub of the plastic blower fan was worn and slipping on the motor shaft. It was still moving a good bit of air, just not quite enough.

Replacement fan fixed it 100%.



If it ain't woke... don't fix it.
November 29, 2019, 10:32 PM
shovelhead
Are you sure they gave you the correct switch? Another possibility is a defective switch.


-------------------------------------——————
————————--Ignorance is a powerful tool if applied at the right time, even, usually, surpassing knowledge(E.J.Potter, A.K.A. The Michigan Madman)
November 30, 2019, 12:16 AM
Excam_Man
Thermal limits blow because of excessive heat. Why?

Not moving adequite air to keep temperature with-in spec:
* Plugged lint screen
* Plugged vent piping
* Plugged or frozen vent cap
* Broken or worn blower wheel

Or excessive heat due to a sticking thermo-disc (thermostat).

Since you've already check the airflow, check out the blower wheel. If ok, change the thermo-disc (thermostat).




November 30, 2019, 02:09 PM
nosticks
I had this happen. I had an unusually long vent run with some curves and elbows. After a year or so of no problem, the over temp tripped and kept shutting down the dryer. Had the vent cleaned. Problem solved.


Awake not woke
November 30, 2019, 02:13 PM
Snapping Twig
quote:
LER5636EQ3



https://www.searspartsdirect.c...r5636eq3-dryer-parts

Part #9
November 30, 2019, 04:10 PM
thumperfbc
quote:
Originally posted by PowerSurge:
Check that the thermistor is still working and that it isn’t covered in lint.


It checked out via multimeter but I could pull it and change it out too. One came with the cut-off.

quote:
Originally posted by Aeteocles:
Lint trap change regularly, or changed *every* time?


I clean it every time I use it......... my bride isn't so good with that despite explaining the hazards involved

quote:
Originally posted by cparktd:
I had one do very similar. An ~18 yr old Maytag. The hub of the plastic blower fan was worn and slipping on the motor shaft. It was still moving a good bit of air, just not quite enough.

Replacement fan fixed it 100%.


How did you diagnose the wheel needed changing? Was it by sound? Did it weeble-wobble?

quote:
Originally posted by shovelhead:
Are you sure they gave you the correct switch? Another possibility is a defective switch.


Reasonably sure unless the part number on the package was incorrect.

quote:
Originally posted by Excam_Man:
Thermal limits blow because of excessive heat. Why?

Not moving adequite air to keep temperature with-in spec:
* Plugged lint screen
* Plugged vent piping
* Plugged or frozen vent cap
* Broken or worn blower wheel

Or excessive heat due to a sticking thermo-disc (thermostat).

Since you've already check the airflow, check out the blower wheel. If ok, change the thermo-disc (thermostat).


I've actually got the thermostat on hand. It came packaged with the cutoff so I can just swap it out.

quote:
Originally posted by nosticks:
I had this happen. I had an unusually long vent run with some curves and elbows. After a year or so of no problem, the over temp tripped and kept shutting down the dryer. Had the vent cleaned. Problem solved.


I get that but the dryer has been in place, I've cleaned it out a couple times, most recently last night. Not much came out this time. Last time (the first time I cleaned it) I got enough out of the ductwork to build a medium sized dog. It was very bad.
November 30, 2019, 06:55 PM
PowerSurge
Since the thermistor checks out, it’s more than likely the thermostat or blower wheel. Many times the blower seems to be putting out enough air but isn’t.


———————————————
The fool hath said in his heart, There is no God. Psalm 14:1
December 02, 2019, 12:55 PM
cparktd
quote:
Originally posted by thumperfbc:
How did you diagnose the wheel needed changing? Was it by sound? Did it weeble-wobble?


Well... This was an old washer / dryer set I let my daughter have after we bought new ones 4 years ago. Because the dryer was so old I just went by the local family owned appliance shop where I had bought my new set to look at a new dryer for my daughter.

They told me to check the blower after I told them about the problem, said it was a common enough problem that they keep one in stock. I was surprised they could even get parts for one that old! I pulled the front off and sure enough It was loose on the shaft. It was easy to replace and wasn't very expensive either.



If it ain't woke... don't fix it.