"Maytag Neptune Electric Clothes Dryer - Shuts Off Prematurely"

 By Ron Stultz

 

 

Summary: in my case, dryer vent hose/pipe to outside was significantly clogged with lint. Once dryer vent pipe clear of as much lint as possible, dryer working again. Point being made here is that dryer has limited error codes and does not display error code when dryer vent is clogged.

 

Background:

Maytag Neptune electric clothes dryer bought new in 2006.

Model: MDE9700AYW

Clothes dryer heating but no matter setting used from timed dry to automatic drying, dryer turns off prematurely leaving damp clothes in drum.

No error codes displayed on control panel.

Long term in-home maintenance contract bought at time of purchase but from previous use of contract with Maytag Neptune washer, know that contract does not cover a everything and thus wise to attempt to determine cause of problem before contacting contract warranty service.

 

Diagnosis:

Because dryer heating, drum turning and control panel appearing to be functional, decided to look at dryer lint condition.

Removed dryer lint trap in front of dryer and using small vacuum head, cleaned as much lint as possible out of the line trap hole.

Started dryer again on timed dry but it shut off after just a few minutes of a 40 minute dry setting.

Some sort of heat sensor related problem??

Pulled dryer out of wall and disconnected dryer vent hose from rear of unit.

Discovered vent hose had significant lint where it makes horizontal to vertical turn up wall to outside.

Not knowing condition inside dryer, examined rear of dryer to discover only access in is small access panel at bottom.

Removed Phillips head sheet metal screws holding access panel to back of dryer and removed panel.

Using flashlight, discovered no lint in internal discharge tube but lint inside dyer enclosure and removed with vacuum.

Observed heating tube on left side with 2 sensors installed.

One sensor installed flush to heating element tube and one 1/2 inch away from heating tube but small hole in heating tube allowing air to come out of tube to sensor.

Also observed electric motor on right front of dryer with drum rotation belt attached and although could not see, fan attached that is inside plastic shroud that holds lint filter in front of dryer.

With dryer vent hose off rear of dryer, started dryer on timed dry.

Dryer heated and ran timed amount as it should.

Reconnected dryer vent hose temporarily and started dryer again and again it began to heat but shut off prematurely.

In my case, vent hose from dryer to outside has been in place for 20+ years without any sort of significant cleaning effort done.

Cleaned dryer vent pipe and replaced outside wall dryer pipe vent cover. "How to - Clean Dryer Vent Pipe"

Dryer repaired.

 

Theory of premature shut off:

From observing inside of dryer, it appears:

- Motor that turns drum also turns a fan that sucks air from the drum down over the lint trap in the front of the dryer and pushes it out the back to the dryer vent pipe.

- When drying is activated via the front panel, the heating element in the metal heat tube inside the dryer begins to heat up and heat from it is pulled via the drum-turn motor, out of the rear of the drum, across the tumbling clothes, across the lint filter and out the dryer vent pipe.

- One sensor fixed hard to the heat tube is an actual heat sensor.

- The other sensor, which sits back a half-inch or so from the heater box, right in front of a small hole in the heater box, is a unit "high heat" sensor.

- This high heat sensor shuts down the dryer if enough hot air is blowing out the hole in the drying tube onto the sensor.

Shutting down the dryer in the case of a blocked dryer vent tube is a great idea, but should have kicked off some control panel code to indicate nature of problem.