Dryer Basics - How They Work

To get a deeper understanding of how clothes dryers work, let's look at four areas of a dryer:

#1 The control panel

The control panel is made up of at least two of the following components:

  • Timer
    The timer is usually the largest dial on the main control panel. It may be a mechanical device much like a simple clock. Or it may be completely electronic, which is just a digital readout.
  • Start switch
    After you have set the timer to the proper cycle, you press or turn the start switch to begin the cycle. The dryer shouldn't run until you do this.
  • Selector switches or knobs
    Most dryers have one or more other switches or knobs on the control panel. They let you adjust certain settings of the dryer, such as heating temperature, end-of-cycle signal, timer cycle, and so on. Normally, the dryer functions, running the cycle selected by the timer, regardless of how these switches or knobs are set.

#2 The door switch and interior light

There is usually a door switch inside the main cabinet of the dryer. Look for a button or small lever protruding from the main cabinet on or near the dryer door frame. When you close the dryer door, it contacts the button or lever, which activates the switch and lets the dryer operate if it's started.

When you open the door, the switch interrupts the power to most of the dryer's internal components and turns on the interior light, if there is one.

Warning! If the dryer doesn't stop when you open the door, don't use the dryer! If you use a dryer that has a defective door switch, serious injury may result.

#3 The drive motor and related parts

Your dryer motor serves three main functions:

  1. The drum is turned by the motor; the drive belt attaches to one side of the drum.
  2. If the drum doesn't rotate at the correct speed, the heat doesn't turn on.
  3. A fan blade is attached to the other side of the drum and draws warm air through the drum and pushes it out the exhaust vent.

#4 The burner assembly and related parts

The burner assembly for an electric dryer consists of a heating element and one or more thermostats. In a gas dryer; the thermostats, gas burner, control valve, igniter and sensor collectively make up the burner assembly. Either electricity or gas supplied to the heating element is turned on and off by the timer, as follows:

  1. First--when you close the dryer door, set the timer, and press or turn the start switch--the motor starts. When it reaches full speed (in about a second), a switch on the motor turns on, which allows electricity to flow to the heating element through a thermostat.
  2. The heating element then glows red hot. Air from the blower flows over the element, through the drum and out the exhaust vent.
  3. When the dryer reaches the pre-set drying temperature, a thermostat turns off the flow of electricity to the heating element.
  4. When the temperature in the dryer falls about 20 to 30 degrees, the thermostat turns on the power to the heating element again and the cycle starts over.
  5. If you selected the Automatic setting, the cycle continues until the clothes are dry, then the timer advances and turns the dryer off. If you selected a timed setting, the cycle continues until the time has expired, then the timer turns off the dryer.
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