Maytag LDE412 Series 2 Dryer

[qsd-dan]

There's no sensor or electronic control unit on a 412, this design uses a more basic approach where the timer only advances when the heating element is off. It's not as accurate as the electronic version but its fairly accurate and better than timed dry. On the auto dry feature, the timer should advance when the heating element is off.

 

The basic areas of failure are a dead timer motor, bad timer, bad regulating thermostat, or a weak high limit thermostat that's cycling at a temperature below the regulating thermostat. Airflow problems also contribute such as a clogged or restricted exhaust duct, clogged blower wheel/housing, and stripped blower wheel (this is common at the age of this machine), 

 

Let the diagnosing processes begin....

 

Select time dry or air fluff. Does the timer advance?

 

[DADoES]

 
Also known as thermostatic autodry (vs moisture-sensing autodry).  Premise of operation being that the heating runs for longer periods at start of the cycle to reach and maintain the target temperature when evaporating moisture tends to hold-down the air temperature, and the timer accordingly runs less.  Heat runs less and the timer runs more as the clothes progress toward dryness, less moisture evaporation and holding heat longer ... so the temperature curve moderates the drying time.

 

[lesmac]

Thanks for the quick reply. The timer does advance on the time dry and air fluff settings. Just double checked the air flow at the vent on the exterior of the house. Flow is strong and ducting is open, if a bit linty.

 

[qsd-dan]

Timer motor is functioning ok...

 

Does the problem exist using either the regular and low temperature settings?

 

[lesmac]

Sorry, I can only respond once every 30 minutes as a new member.

Generally we don't use the low temperature setting, just regular.

If I understand the operation correctly, it sounds like either a regulating thermostat or the high limit thermostat are not functioning correctly, which could result in the unit heating more/longer than it should based on the temperature/moisture levels. This would prevent the timer from advancing during the "heat-off" cycles and cause longer run times and over-dried clothes.

The dryer has seemed to be operating at a higher temperature than we are used to. The top of the unit gets uncomfortably hot to the touch. This would seem to indicate that the regulating thermostat that turns off the heat for a bit is not functioning correctly and the heat only shuts off when the High Limit Thermostat is triggered. Does this sound correct?

 

[qsd-dan]

The dryer has seemed to be operating at a higher temperature than we are used to. The top of the unit gets uncomfortably hot to the touch. This would seem to indicate that the regulating thermostat that turns off the heat for a bit is not functioning correctly and the heat only shuts off when the High Limit Thermostat is triggered. Does this sound correct?

 

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I agree. 

 

This dryer uses 2 cycling thermostats, regular and low. If the dryer functions correctly on the low temperature setting, the regular cycling thermostat is probably shorted inside and the dryer is cycling off of the high limit thermo.

 

Incase you never been inside the dryer, this is how to remove the front panel in order to gain access to the thermostats on the blower housing.

 

 

[combo52]

Maytag dryer not shutting off properly on auto dry cycle

First thing I would do is make sure the entire exhaust system is completely clean.

While you have the dryer pulled out reach all the way back inside the exhaust pipe on the dryer and clean it all the way to the front of the machine.

You may also want to take the front off the machine and the front of the Tumblr off and clean completely going into the blower if this hasn’t been done in many years.

As Dan mentioned make sure the blower wheel is tightly attached to the motor shaft when you’re doing this.

John L

 

[lesmac]

It appears that the low heat Auto Dry cycle is working correctly. This should mean that the 150 degree (regular) heat thermostat is malfunctioning. Sounds like a fairly easy fix.

I appreciate all the assistance.

 

[qsd-dan]

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