Instructables

Dryer won't heat up

Picture of Dryer won't heat up
 The other day I noticed that the load of clothes was taking forever to dry.  I opened the dryer door and everything was cool to the touch.  I will try to show you how I troubleshot this problem.  Hopefully it will be informative.  This was a Kenmoor series 90 dryer.
 
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Step 1: Unplug the dryer

First pull the dryer out away from the wall and as with all things electrical, unplug it! 

Step 2: Remove the front panel.

Just pull on the front panel, it should just pop off.  On the inside of the panel is the electrical schematic.  Look it over there are a few things that you want to find, such as the operating thermostat, thermal cutoff, high limit thermostat and the heating element.  These should all be in a row wired in series.  If any one of these things is bad, then none of it will work.

Step 3: What is inside?

Inside on the right you will notice the heater box.  On that heater box is all of the switches and thermostats, with the exception of one, the operting thermostat.

Step 4: Get your meter.

Now take your meter out and set it to Ohms.  First test the heater coil.  It should read between 7.8 and 11.8 Ohms , mine read 10.2, which means that it is good. If it reads that it is open (my meter reads '1' when it is open) then you need to change the heater element.
 Then I checked the next thermostat back, the high limit thermostat.  That should be normally closed.  So the meter should read that it has continuity. Mine checked out ok.
The next one back, is the thermal cutout switch.  this is designed to stop all flow if the temp ever gets above 350 deg F in the heater box.  Mine, as you can see in the third picture is bad.  Im not sure why it overheated but it will be replaced.
Phil B3 years ago
We had a dryer that heated up, but did not dry the clothes. It turned out to be a blockage in the vent pipe. The venting went under the house and ran for about 40 feet. The elbow where the duct went from vertical to horizontal under the house was the low point. Water, probably from condensation, had collected there and completely blocked air flow. We determined that the dryer produced adequate heat, but there was no air flow at the trap door flap on the side of the house. We suspected it was blocked with lint. A long brush for the purpose of cleaning dryer vents came up very wet when we sent it down the tube. That helped a lot in identifying the problem and its location.
Phil B3 years ago
I do not know how I missed this. Very well done! This is very helpful. Thank you.