WTMC3300US/02 Bosch Dryer - Thermal Reset tripping

SC Tiger

Premium Member
Joined
May 17, 2019
Messages
4
Location
Seneca
Model Number
WTMC3300US
Brand
Bosch
Age
More than 10 years
I have a Bosch Nexxxt dryer that is >10 years old but has developed a problem. The thermal reset on the side of the heating element keeps tripping. I reset it last night and used the dryer and it ran two loads, but on the second it tripped the reset again.

I've ordered another reset but do these things actually go bad? Since it will reset and then will get hot I think the element is okay. I tried to clean the lint out of the element the best I could - when I get the new one I plan to do a more thorough cleaning.. The thing that is puzzling me is that it will be okay for one load but the next it goes out, which tells me that it is an issue with either accumulated heat or the reset has gone bad. The exhaust tube is clear - has some lint along the sides but isn't clogged at all.

Could the issue be the temperature sensor that is in the heating vent?

If the element itself is bad I may just replace the dryer. It's getting some age on it and I don't want to have to keep throwing parts at it, but a $40 reset I'm willing to do.

Thanks in advance.
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
102,105
Location
McMullen Valley, Arizona
Hi,

Are you referring to this thermostat:
00422272 Limiter-Temperature


Yes, they can just wear out after 10 years.

You have to make sure you clear all the lint out of the dryer, they are very sensitive to air flow through the heating element.

Could the issue be the temperature sensor that is in the heating vent?
Do your clothes seem too hot when they come out of the dryer?

I'd start using MEDIUM HEAT instead of HIGH HEAT. I never use HIGH HEAT on my dryer and the clothes come out perfect every time.

Jake
 

SC Tiger

Premium Member
Joined
May 17, 2019
Messages
4
Location
Seneca
That's it. I ordered it and the other thermostat just in case. Mainly because shipping was kinda expensive and I didn't want to pay it twice.

Would a bad/shorted heating element do what I'm seeing (work for one load but trip the thermostat on the next one)? How would that behave?

Plan is to give the heating element a good clean and inspection when I replace the thermostat.

Thanks for your help.
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
102,105
Location
McMullen Valley, Arizona
If the heating element was grounded it would heat in the AIR FLUFF/NO HEAT cycle.

Try it in AIR FLUFF/NO HEAT cycle and see if it gets hot.

Jake
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
102,105
Location
McMullen Valley, Arizona
Ok, sounds good, yes keep us posted.

Jake
 

SC Tiger

Premium Member
Joined
May 17, 2019
Messages
4
Location
Seneca
So far it works fine on lower heat and doesn’t trip the thermostat. This thing doesn’t really have heat settings so much as damp dry, dry, really dry, and burned to a crisp or something. But the lower settings do seem to produce less heat.

Last night I pulled the heater, cleaned it with compressed air and did a ground check. No continuity from the element to the heater housing but continuity from one end to the other. So all good there. Also cleaned out as much dust and lint as I could.

Will put the new high limit thermostat in once I get it just to be safe.

Thanks again for your help.
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
102,105
Location
McMullen Valley, Arizona
Excellent SC Tiger, glad to hear that.:)

Thanks for the update!

Jake
 
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