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#1 Posted : Tuesday, November 8, 2011 9:52:06 AM(UTC)

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Joined: 1/4/2011(UTC)
Posts: 11

The other day my wife told me the dryer didnt' appear to be working right - wasn't heating up. After some research, I figured out that the thermal circuit fuse that is mounted to the upper portion of the heater box was no good. Testing continuity across the legs on this component showed an open circuit (full resistance). After replacing (can't purchase separately btw - comes paired with the t-stat mounted to the lower portion of the heater box), the dryer worked again. I watched as the heater element coils lit up and glowed. I also cleared whatever obstruction I could re; vent system since I'd heard this is usually the culprit of an overheat condition with dryers.

Confident that I had fixed the problem, I put everything back together. However, the fuse didn't last through a complete dry cycle. Cold again with damp clothes (no drying) :-( That was yesterday.

Trying to wrap my arms around how everything works and how the vent system is crucial to proper operation that prevents overheating. What puzzles me is, if I temporarily jump the wires that are connected to this (now) bad fuse, the heat elements glow (normal since that's what is supposed to happen). After the dryer reaches what I perceive to be operating temperature, the t-stat trips and the elements shut off. That said, now the dryer starts drawing cooler air through which should, for all intents and purposes, cool the dryer. Why would it matter if there is a restriction in the venting system if the coils on the heating element are turning on and off with the t-stat? And why or how, if that is the case, would the therm. switch keep blowing?

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#2 Posted : Tuesday, November 8, 2011 6:17:59 PM(UTC)

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Here are your parts
Replacement parts for WHIRLPOOL LE5720XSW0 Residential Dryer |

See the attachment for a wiring diagram. I could not find a XSW0 so diagram is for a XSW1 which should be close it not the same.

[COLOR="DarkRed"] And why or how, if that is the case, would the therm. switch keep blowing?[/COLOR]
The cycling thermostat is on the blower assembly and you are blowing the thermal cutout on the heater assembly basically you are measuring the temperature in a different temperature zone so that can cause problems. As an example lets say room air is being sucked into the air flow path before the cycling thermostat, it sees a cooler temperature so turns off when the heater is hotter than it should be. Plus there are other possibilities.

[COLOR="DarkRed"]Why would it matter if there is a restriction in the venting system if the coils on the heating element are turning on and off with the t-stat?[/COLOR]
It all depends when they turn on/off. Also usually it is the thermal fuse that blows when there is a vent restriction.

Check the heating coil.
Unplug the unit and both wires to the coil.
Check it with a meter, should be around 10 to 12 ohms.
Then check from each side of the coil to the case/frame, both should be infinite ohms (open). If not the coil may have sagged or broken and is touching the case. This can cause it to run on high and the thermostats cannot regulate it so the thermal cut-off blows.
In your case it could be that it has failed in such a way that the thermostat can control it but it is putting out too much heat on a short piece of the element and pooping the ther,mal cutout.

The hi-limit should have regulated the temperature so the fuse did not blow, that is why there is a new one with the thermal cut-off..
Note: That unless there is another problem in the unit the hi-limit should never have to open. It is just a safety device with the fuse being a backup safety device.

Just in case it is not a grounded element.
With all the below the high limit will also have to be replaced.
Check that the belt is OK.
Check the seals (drum etc) in the unit. The air is pulled over the heating coils, through the drum and pushed out the exhaust. So any large seal leak will pull in room air and the cycling thermostat on the blower will run the unit hot.
Check that the lint filter is not coated with fabric softener residue which greatly reduces air flow.
Check/clean your vent system.
Check/clean the blower wheel.

If all OK you may want to replace the cycling thermostat as it's contacts may not be opening at the correct temperature.
File Attachment(s):
LE5720.pdf (31kb) downloaded 25 time(s).

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#3 Posted : Thursday, November 10, 2011 7:27:14 AM(UTC)

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Thanks, denman.

After tearing down the vent system and cleaning out thoroughly - lint chute, blower motor, vent hose leading out the side of the house, checked lint screen, and the bulkhead opening that feeds to the lint chute (can be seen from inside the drum through door on the upper right of the bulkhead), I replaced the fuse again and it seemed to do the trick.

Heating elements turn on and off with the t-stat as expected and the dryer doesn't seem to overheat any more.

Looks like a good fix. Thanks again.
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