Kenmore dryer: why thermal cut off fuse?
#1
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Kenmore dryer: why thermal cut off fuse?
Why is it needed? Ive only repaired a few dryers, but this looks like extra part. This dryer has the std High-Limit Thermostat, Operating Thermostat, and Thermal Fuse. However, it also has this Thermal Cut-Off Fuse. This Thermal Cut-Off fuse is located in the heater housing where it feeds the drum and looks more like a thermostat. Its also the most expensive part.
See attached diagram.
#1 Thermal Cut-Off Fuse
#34 High-Limit Thermostat
#42 Operating Thermostat
#59 Thermal Fuse
kenmore 110.96281100
tks,
pa
See attached diagram.
#1 Thermal Cut-Off Fuse
#34 High-Limit Thermostat
#42 Operating Thermostat
#59 Thermal Fuse
kenmore 110.96281100
tks,
pa
#2
That is the first fuse that blows when the vent is clogged. Also ill blow if the heater is shorted. Have only seen this a few times. If you want the heater or thermostats to quit take it out and than the most expensive parts will go.
#3
Edit buttons don't work so a new post. Looking at picture are you talking about the thermostat at bottom of heater? If so I have never seen that one go out and I repaired dryers for many years, They come in a as a pair when you buy them from Whirlpool so I usually replaced it any way.
#4
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They are all there for a reason.
The thermal cut-off and hi-limit protect the heater from overheating,
The heating coil can break and short to the case then that part of the coil becomes an uncontrollable hot area.
Also if the lint filter is clogged the heater can overheat due to low air flow through it.
Plus a few other things.
When this happens the heater runs on the hi-limit. Unfortunately most of the time people do not notice that the dryer is running hot so it keeps doing this. Also the hi-limit's contacts are not as good as the control thermostat's contacts so in time they fail. Often they fail by welding together then the thermal cut-off blows. That is why they are sold as a pair because the thermal cut-off should not blow unless the hi-limit has failed/shorted.
The most common cause of the thermal fuse to blow is a partial or full clog of the dryer vent.
It blows to protect against vent fires.
And the thermostat is there to control the temperature.
The thermal cut-off and hi-limit protect the heater from overheating,
The heating coil can break and short to the case then that part of the coil becomes an uncontrollable hot area.
Also if the lint filter is clogged the heater can overheat due to low air flow through it.
Plus a few other things.
When this happens the heater runs on the hi-limit. Unfortunately most of the time people do not notice that the dryer is running hot so it keeps doing this. Also the hi-limit's contacts are not as good as the control thermostat's contacts so in time they fail. Often they fail by welding together then the thermal cut-off blows. That is why they are sold as a pair because the thermal cut-off should not blow unless the hi-limit has failed/shorted.
The most common cause of the thermal fuse to blow is a partial or full clog of the dryer vent.
It blows to protect against vent fires.
And the thermostat is there to control the temperature.
#8
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You find me make and model numbers of the units that do not use these and I will try to answer your question.
What other fuse?
Above I thought I covered the thermal fuse (on the blower) and the thermal cut-off (on the heater assembly)
What other fuse?
Above I thought I covered the thermal fuse (on the blower) and the thermal cut-off (on the heater assembly)
#10
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Ive watched several troubleshooting videos for this specific model troubleshooting for no heat. Each video tested the High-Limit Thermostat, Operating Thermostat, Thermal Fuse, heating element. One of the videos tested the timer. None tested or even mentioned the Thermal Cut-Off Fuse.
#11
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Still need model numbers!!!!
For a no heat problem you check the thermal cut-off.
If the thermal fuse blows then the unit will not start.
For a no heat problem you check the thermal cut-off.
If the thermal fuse blows then the unit will not start.
#12
Those safeties are installed by the maker to give you the best chance of not burning your house down.
Relace it.
Relace it.
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Before I purchase new cut off, I decided to test the two thermostats:
one is marked L155-25F. it opens at 110°F.
the other L250-80F. it opens at 180°F.
Some sites say that number after the dash is +/- for opening temperature. Other sites say that is how much less the temp needs to be for closing. I dont know which sites are correct.
one is marked L155-25F. it opens at 110°F.
the other L250-80F. it opens at 180°F.
Some sites say that number after the dash is +/- for opening temperature. Other sites say that is how much less the temp needs to be for closing. I dont know which sites are correct.
#17
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No I would say that they are OK.
I do not know how you tested them to determine the trip temperature.
And I do not know how the manufacture came up with that spec.
As long as they open and close then I would not replace them.
There is onne scenario where the thermal cut-off can blow but the hi-limit is OK.
And that is when a heating coil breaks and part of it touches the case (grounded). It will then run uncontrolled and if it is near the cut-off it will blow,
I do not know how you tested them to determine the trip temperature.
And I do not know how the manufacture came up with that spec.
As long as they open and close then I would not replace them.
There is onne scenario where the thermal cut-off can blow but the hi-limit is OK.
And that is when a heating coil breaks and part of it touches the case (grounded). It will then run uncontrolled and if it is near the cut-off it will blow,
#18
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One other thought I had was did you use a meter to check that the contacts actually opened or did you just listen for the click?
I always use a meter!!!
I always use a meter!!!