Recently, we had a dryer that seemed to be getting too hot.  This went on for a while and then suddenly it stopped and would not run.

After much research we found that an electric dryer usually has one or more control thermostats which regulate the temperature around 120-150 degrees.  If this thermostat fails, there is a Hi-Limit thermostat which is often on top of the heating element, which will take over but keeps the temperature at 240-260 degrees.  That is more like “baking” your close instead of drying them.

Often, when the control thermostat fails (if it fails in a closed stat), your dryer will seem to get quite hot and may even have a hot smell.  This is time to check three possible issues:

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1:
Check that the vent is not blocked in any way.  Blockage or bad flow and overheat your dryer among other things.

2:
Take the vent off the back and run part of a load -
Is it pumping out a lot of air?  If not, your problem might be related to the dryer motor or blower not having enough power to pull the air through.  Since the air is not flowing well, it might not get to your control thermostat and the Hi-Limit one is taking over.

3:
More than likely the control thermostat is sticking or failed and probably needs to be replaced.
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If all your dryer does not run at all, it could be the thermal fuse typically located near the heating element.  This fuse will shut down the motor once it senses the dryer reaching a certain temperature.  As the name implies, it is fuse, not a thermostat.  That means, once it triggers it is set open and must be replaced.

If the thermal fuse is blown, it is possible that your control and hi-limit thermostats failed and they may need to be replaced also.

If the dryer does run, you can get a thermometer that goes up to at least 300 degrees and place it in a sock and run the dryer until it seems hot.  If the temperature is over the upper limit of the control thermostat and more like the range of the upper thermostat, you know the control thermostat is not working.

The price of these parts can vary, but if you check out ebay, you can usually find a good buy.  Parts locally for our dryer (including the heating element) would cost over $100 but on ebay we get them for just under $40 including shipping.