Today dryer manufacturers are starting to switch over from timers, to dryer electronic controls. Electronic controls are less expensive to manufacture, and for the most part more dependable than a dryer timer. That’s because dryer timers are mechanical. Of course anything mechanical will eventually fail. A dryer timer is usually made up of a metal housing, with a small motor secured to the outside of the housing. The motor is connected to a series of gears, that rotate cams, that open and close switch contacts within the timer. Imagine for a second that a dryer console had a series of push-button switches running from left to right. Now imagine that these push-button switches controlled the loads on the dryer. One switch controls the motor, another switch controls the heater, and so forth. If you were to walk up to this imaginary dryer and push the switch that controls the motor, the motor would start, and the dryer drum would rotate. And if you had clothes in the dryer, you could push the next switch that completed the circuit to the dryer heater. Now you have a dryer that is tumbling the clothes with the heater on.
We all know that taking clothing out of a hot dryer before it has time to cool down, will cause the clothes to wrinkle. So using our imaginary dryer, you would have to set the timer on your wristwatch or cell phone, to estimate when the clothes were dry. This way you could put your beer down, put the football game on pause, and run back to the dryer and push the switch that would turn the heat off. The drum would continue to rotate, because the switch for the motor was still depressed. After 15 minutes or so, you could return to the dryer, and depress the switch to disengage the contacts for the motor, the dryer would shut down, and now you could remove the clothing that is dry and cooled down.
Fortunately, dryer timers have motors on them, and a series of gears and switches that control the motor and the heater, permitting you to enjoy your beer and football without all that unnecessary exercise. During the dryer design process, the engineers decide how long a set of switch contacts inside a dryer timer should be closed, to control specific loads. The manufacturer of the timer uses this information to manufacture the gears and cams within the timer to accommodate that time frame.
The good news is, dryer timers rarely fail. In fact, probably 60% of dryer timers purchased are unnecessary. That’s because a dryer timer is the most misdiagnosed component on a dryer. The interesting thing about that is, most appliance parts sales outlets, do not allow the return of timers that have been installed. Therefore if you misdiagnosed the problem and assume it is the dryer timer, it is yours to keep.
More info: http://www.mckinneyappliancerepairllc.com/