I assume a blockage in the exhaust might? I don’t think that is the case as I cleaned it out about 12 months ago after no cleanings for probably 6-7 years. An ungodly amount of crap came out then.

Does age do these fuses in or do I need to be looking for a cause and the blown fuse is a symptom?

Fuse is confirmed bad thanks to YouTube.

Two years ago I replaced the Thermal Fuse (and the Thermistor, which tested within spec, but you're supposed to replace both at the same time) on a Kenmore/Whirlpool Dryer of 1998 vintage. A year later I had the same issue...an open/cleared Thermal Fuse. The second time, I also discovered a failed (exploded!) Heater Relay. I believe the Relay was the issue all along and that it caused the first Thermal Fuse to clear as well. I do not believe it was not reliably opening at times and it shorted/welded when it failed.

FYI - The first time around, all of tests in the troubleshooting docs pointed to a bad Thermal Fuse, but did not identify the cause. We had found the dryer not running but hot enough that it ruined/cooked some permanent wrinkles into some poly active wear that was in the dryer at the time. The 2nd time, SWMBO indicated she smelled something. I found the dryer running, but REALLY Hot, so I shut it off....Duh! Anyway, after I removed the clothes from the drum and removed the lower access/kick panel to get the heat out of the dryer, once again I found an open/cleared Thermal Fuse. I also found that regardless of setting, including Air Fluff, the Heater was ON. I opened the switch/control panel and discovered the Heater Relay failure!

A picture is worth a thousand words! Hope this helps...

I’ll pop that panel and see if I have any signs of that sort of failure for sure.

I cleaned out the exhaust shute in the dryer itself. Some gunk in there but nothing spectacular except 3” construction nail in the blower fan housing (no idea how that got there). I’ve never noticed it getting excessively hot. I read that a malfunctioning thermostat might cause the thermal fuse to blow by not shutting of the heating element. It suggested temporarily bypassing the bad fuse and running the dryer with a medium wet load in it but without the exhaust pipe hooked in. The test procedure said to measure output temp and that it should climb to 150 then the element should shut down until the exhaust is 130, at which point it’d cycle on.

The exhaust never got above 112 despite running for 10 minutes. Maybe the wet clothes were doing too much cooking as the air going in measure at 300.

This message has been edited. Last edited by: thumperfbc,

quote:

Originally posted by thumperfbc:
cleaned it out about 12 months ago after no cleanings for probably 6-7 years. An ungodly amount of crap came out then.

Bad exhaust = big lint in the body of the dryer.

Check the heat vent inside the dryer. Is it burned? Another indicator of a bad exhaust.

Of course a bad cycling thermostat could be involved, but I'd start with air flow out of the house.

I have to look at dryer vents occasionally in my professional and I can't believe how bad many are and how stupid some people are in running them.

First: short... then: less turns.... no plastic flex anywhere.... 4" diameter.... and rigid pipe should be taped with metal tape and no screws....

quote:

Originally posted by Snapping Twig:

quote:

Originally posted by thumperfbc:
cleaned it out about 12 months ago after no cleanings for probably 6-7 years. An ungodly amount of crap came out then.

Bad exhaust = big lint in the body of the dryer.

Check the heat vent inside the dryer. Is it burned? Another indicator of a bad exhaust.

Of course a bad cycling thermostat could be involved, but I'd start with air flow out of the house.

I cleaned out all the vent ducting again. Not much came out. The lint screen itself was pretty packed when I initially looked at the dryer but frankly, it’s been much worse so I didn’t think it was the issue.

I’m thinking I should get another thermal fuse on hand in case this happens again. Maybe it’s prudent to change out the cycling thermostat as well as a precaution?

What make/model dryer are we talking about here? If a Whirlpool/Kenmore, there are typically Elec Dwgs and troubleshooting docs behind the control panel....Other manufacturers likely do this too.

quote:

Originally posted by nhracecraft:
What make/model dryer are we talking about here? If a Whirlpool/Kenmore, there are typically Elec Dwgs and troubleshooting docs behind the control panel....Other manufacturers likely do this too.

It is a Whirlpool LER5636EQ3

quote:

Originally posted by thumperfbc:
I assume a blockage in the exhaust might? I don’t think that is the case as I cleaned it out about 12 months ago after no cleanings for probably 6-7 years. An ungodly amount of crap came out then.

For a long time, either I or Brad would post yearly about cleaning dryer vent runs. Just as you'll see members post about changing smoke batteries.

Cleaning your dryer vent yearly both prevents a fire risk, and helps the dryer operate efficiently.

I've seen some bad ones in my travels renovating homes, with only 1.5" of free space left in the "duct." These things can absolutely cause a house fire, gas dryers are slightly more of a risk than electric dryers.

If most of the run of your dryer vent is visible, hard pipe it with as few 90 degree turns as possible. Flexible plastic ducting should absolutely be avoided, and the stiff AL flexible pipe should be used if rigid won't do it.

Make sure and check the dryer cap outside the house have seen the louvers there either stick closed or only partially open.