Whirlpool dryer overheating, replaced thermostats

Dryer Repair
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1

I have tried everything I know to figure out why this dryer is overheating. And I mean really dangerous, fire starting level heat. The drum has deformed slightly due to the heat.

The problems started with the timer. Before this the dryer has worked perfectly for years. I’ve kept it clean, removing the back… removing everything that can be removed to clean lint out from time to time.

But a few weeks ago the dryer died during operation. The fuse blew and the contacts in the timer shorted out. But it would run on the eco setting where it senses the moisture and only runs as long as is needed.

So I replaced the fuse and ran the dryer on the automatic dry function. Well after a couple of weeks of that I lucklly went to the laundry room and it was unbelievably hot in the room. I thought there actually was a fire in the walls because it was SOOO hot in the room and there’s no other type of heater in there. The dryer was so hot on the top and sides it burned my hand so bad I thought it was going to blister.

Well, I replaced the fuse again since I thought it should had blown or something but it didn’t.

I found a brand new timer on ******** from someone that bought the wrong one and I got it dirt cheap. I’m sure that in itself couldn’t cause the overheating issue but I’m just listing parts that I have replaced.

I can’t remember the name of each thermostat but I have replaced all 3 in the back of the dryer.

I took apart everything that could be removed and there’s no lint build up anywhere. The fan is working… there is as much airflow through the vent as it always has. There’s no kink or bend in the vent and it less than a foot to reach the wall.

I have removed the heating element and inspected it multipe times. No part of the element is burned, bent, cracked or broke. The insulators that keep the heating element away from the metal are in perfect condition.

I have tried all the options on the control timer and it makes no difference, whether it’s timed or automatic dry.

It will overheat whether I select low, medium or high.

It will not overheat every time the dryer is run but most of the times it will.

I just can’t buy another one right now. So we have to use. But we do not leave the house with the dryer running. And i set continous 10 minute timers with Alexa for me to go and check the dryer. About 6-7 times out of 10 it will overheat. Monitoring it continously it does reach that dangerous heat level like it did before. but it would if I don’t stop it. I run it 10 minutes and if the top gets warmer than it should I turn it off and wait about 15-20 then start it again and keep doing that until the clothes are dry.

2-3 times out of 10 the dryer will run perfectly from start to end, even if takes 40+ mins to dry everything.

WHAT could possibly be left that could be replaced that is causing this issue?

3

First off good for you being pro-active and cleaning the inside of the machine from lint.
So my question is have you cleaned the entire vent system (duct work) all the way to the exhaust port outside, whether its on the wall or on the roof? Have you verified good airflow at the exhaust after cleaning?
If so have you tried running the machine while its disconnected from the venting to see if it overheats while exhausting into the laundry room?
You say that you have replaced all three thermostats in the back, did that include the cycling thermostat on the exhaust port? It sits next to the thermal fuse and has four prongs. It is part number 8 on the linked schematic.
http://www.appliancepartspros.com/bulkhead-parts-for-whirlpool-wed4800xq0.html

Another thing to check if you happen to use dryer fabric softener sheets, has any of them adhered to the exhaust port inside the drum on the back wall thus reducing airflow? Sometimes if you use to many dryer sheets they can get sucked onto the exhaust port and I have seen them melted to there.
Have you removed the cover from the vent fan to see if the fan blades are covered in lint thus reducing airflow.

So in a nut shell the "cycling thermostat" is responsible for turning the heating element off when the exhaust temp reaches around 160º to 170º it will then turn the element back on when it has cooled down 25º to 35º. Even when you have selected medium heat, the cycling thermostat has a little heater on its top (the smaller two prongs) that will cause it to cycle at a lower temp.
If it doesn’t have proper airflow over it from the drum it won’t shut down properly.
So my best guess is improper air flow and or a bad cycling thermostat.

4

brobriffin said:
did that include the cycling thermostat on the exhaust port? It sits next to the thermal fuse and has four prongs. It is part number 8 on the linked schematic.
http://www.appliancepartspros.com/bulkhead-parts-for-whirlpool-wed4800xq0.html

Another thing to check if you happen to use dryer fabric softener sheets, has any of them adhered to the exhaust port inside the drum on the back wall thus reducing airflow? Sometimes if you use to many dryer sheets they can get sucked onto the exhaust port and I have seen them melted to there.
Have you removed the cover from the vent fan to see if the fan blades are covered in lint thus reducing airflow.

I did replace that thermostat. I also removed everything (I don’t know the specific names of covers and pieces in the back) that can be removed without removing the top and front of the dryer itself. I removed the cover that gave me access to the view the fan completely and I don’t see anything in there or in any exhaust port. There is a high volume of air leaving the dryer when it’s on.

I’ll try replacing the thermostat again. Maybe I got a bad one?

Thank you very much for your time and help.