I recently had a problem with a dryer that was tumbling and not heating. Being lazy I immediately assumed it was the ignitor. When I went to school they taught me to do all the troubleshooting steps all the time and not make any assumptions. But the real world rewards cheaters nine times out of ten and so mostly I don’t do that. But if you play that game, you have to be willing to pay the price when the 10th times rolls around. In this case, it was not ignitor but I was not too upset about that.

I did a little checking with my meter, found that the thermostat was bad and moved on to order the new parts. The problem is that even though the part is called a thermostat, it is not a thermostat. At least in my education, a thermostat refers to a complete temperature control unit. Historically, this is a switch connected to some kind of temperature control. As the temp rises (or lowers depending on the type) the switch opens and visa versa as it closes. You can have other things that meet the definition of a thermostat but regardless you should not call something a thermostat unless it has all the control elements contained in it.

What the new Whirlpool dryers have is a thermistor. A thermistor is a resistor that changes voltages based on temperature. This voltage is in turn interpreted by a computer that is usually located some distance away although a lot of modern residential HVAC electronic thermostats have everything in one wall mounted package (and hence why they are called thermostats). However, in a dryer, the board that interprets the signal is separate from what they are calling the thermostat and so I don’t think they should be calling it a thermostat. It is a thermistor and should be trouble shot like one.

I am just throwing this out there because I did not recognize this just by looking at the part (in retrospect I should have but I have been running a desk for a long time) and I got confused by what my meter was telling me. It was a lot harder then a lazy person like me wants to work to figure out what was going on. All my normal google and youtube searches kept giving me instructions that took for granted that I had a thermostat even though that is not what I had. In the end, I figured it out it was no big deal. But in the off chance that google will work for somebody, I thought I would throw this post out there to help anyone who might be puzzled by what their meter is showing them when they go to check what they think is a thermostat.

The below is how you check a thermostat.

The below is how you check a thermistor.