Whirlpool Dryer LGR4634PQ0 - Blown Thermal Fuse - Seeking Advice

[GoodFerNuthin]

We've got an old gas dryer that's been a reliable workhorse for a number of years (15+ maybe?)  I can't recall it needing any repairs until this past week, when it stopped heating.  An internet search yielded volumes of troubleshooting help, which led me to the thermal fuse located next to the blower motor.  It tested open with my multimeter.  Had my local appliance parts store been open on Sundays I would have spent $12 for an OEM part, but same-day delivery from amazon for a $5 aftermarket part would have to do, and the dryer was heating again in no time.  I didn't open the appliance any more than taking off the rear panels.  I vacuumed up the dust and lint that was easy to get to and did my best version of a prostate exam to feel if there was lint caked inside the exhaust, but it all felt pretty clean.  The 4" flex duct was reasonably clean: definitely free-flowing with just a few lint-wads here and there.  The duct mates directly with a flappy louvred vent on an exterior wall.  When the appliance is running the exhaust moves the flappies around and feels blowy enough to the uncalibrated hand.

All that is to say that it was an easy solution to get running again, and I saw no obvious air-flow obstructions.  The omniscient internet says obstructions or age may cause the thermal fuse to trip.  I could assume it was age and leave it at that, but I wondered if there are other factors I should be thinking about:

• Any operational habits such as underloading or overloading the drum, or running too many loads back to back, etc, that might cause hot exhaust air and a blown fuse.  (We're a household of 6 and run a lot of loads.)
• Any other parts that are bound to be wearing out at this age, for which the thermal fuse could be an early symptom.
• Is it common for there to be a lot of lint packed inside the blower that my stubby fingers couldn't reach, so I should I have opened up the blower housing while I was in there?  

Thanks for any wisdom you can impart.  If it happens again, I'd like to be able to figure out why as quickly as possible.

[EngineeredAppliance]

A thermal fuse trips due to excessive heat to keep it short. If you cycling thermostat is not cycling off and on the heater the high limit thermostat or thermal fuse will trip as a safety measure. If the lint trap is filled with lint which is often time is. This will cause a trip and the units air flow is impeded causing excessive heat. If the lint screen is caked with residue from fabric softener sheets. This impedes air flow. A blower wheel with excessive lint will cause high vibration and excessive heat. Dryer vent clogged with lint. Will definitely trip the thermal fuse. 

 

How often you run the unit. Nah. Yes its extra wear and tear but no not the reason.

Overloading not really the materials just won’t get dry.

If you are a house hold of 6 with long haired humans and pets then you need to tear that unit down probably twice of a year to give it a through cleaning (just vacuum the hotspots I mentioned early).

Haven’t heard of a thermal fuse going open due to age. Kinda makes not sense to me. The half round piece in submerged in the dryer’s internal duct. Duct gets too hot too many times over a specified period of time. It trips the fuse. 

 

[evaappliance]

On 5/9/2022 at 9:39 AM, GoodFerNuthin said:

Any operational habits

opening the door randomly mid cycle to see if the clothes are dry yet 

[evaappliance]

in my experience , old thermals blowing for no reason is a thing  

[Terry Carmen]

Like @evaappliancesaid, sometimes "they just blow".

A thermal fuse is just a tiny blob of solder between two wires, while it will blow if it gets too hot, which usually means an airflow problem or the heat not turning off when it should, they also sometimes blow from getting old.

If it blows again, it's time to start looking at the air temperature and why it's getting too  hot.

[Bluebayou]

I always Iike to open the blower cover/duct to look at the fan.  I have found wads of felt-like lint inside from the lint screen being scraped off (accidentally) and then compacted by reinsertion.  
 

Yes, I have seen older thermal fuses open for no reason other than apparent age.  
 

Tjey are cheap.  Keep a spare.