One of the simplest appliances in your home is your dryer. According to the Association of Home Appliance Manufacturers (AHAM), household dryers have a life expectancy approaching 20 years. Therefore, a dryer is likely to last you a long time and because it is simple, it should be easy to repair when it ails. Understanding how your dryer works can help you pinpoint a problem should you encounter a fault.
Dryers use a combination of heat, air, and kinetic motion (movement) to dry clothes. To understand the 3 forces at work, think about how your clothes would dry on a clothesline. A bright sun and a dry breeze will dry your clothes in a snap. The air moving through the fibers in the clothing, in combination with the radiant heat of the sun, pull and evaporate moisture from your clothes and get them dry. A dryer does the same thing.
All dryers use a heating element (if electric) or a gas burner to generate heat. Air comes in from the environment, passes through this heating element, and goes into the drum. The heated air passes through the clothes, pulling moisture (and lint) with it, and goes out the back of the dryer. The exhaust hose carries the hot, moisture-laden air out to the outside of the house. When the clothes reach approximately 90% dry (or 10% relative humidity), a moisture sensor stops the drying cycle, unless the customer has selected the time-dry option, which keeps the cycle going for the predetermined amount of time. Important footnote: Only use the timed-dry cycle when drying articles, such as shoes, on a drying rack. It is not wise to use it for normal drying because it will cause over or under-drying, consuming more energy and damaging your clothes in the process. Always use an automatic dry cycle.
Most dryer problems relate to installation or use. If your dryer appears to work normally but takes too long to dry the clothes, it means the moisture-laden hot air is not exiting the dryer properly. More than likely a blocked or kinked dryer vent is the likely culprit, and it is the single most important cause of dryer fires. Clean out your dryer's vent hose, eliminate excess hose and unnecessary kinks and bends and your dryer will work much better and save energy.
To gently and safely dry clothes, dryers use several thermostats and thermal fuses to keep the dryer operating at proper temperature. The temperatures range from 125 degrees F for the most gentle cycle, to about 165 degrees F for the high temperature settings. These thermostats monitor not only temperature but also moisture, in combination with moisture sensors in some dryers, to dry quickly and gently. A fail-safe mechanism prevents the dryer from working if there is a failure in one of these thermostats. Also, an electrical spike will cause the thermal fuse to blow out, rendering the dryer dead. The most common cure for a dead dryer is simply to check the breaker switch and turn it back on, or to replace a blown fuse. But beware: If a fuse blew, that means there are other electrical or heat problems you must look for as the root cause of the problem, because if the problem continues unsolved, the fuses will continue to blow out.
Aside from the thermal fuses and thermostats, the only other things that a dryer needs replacement are: The heating element (about every 10-15 years), the support rollers, the belt, and the motor. The heating element will wear out after continued use and once replaced, assuming the dryer is in otherwise good condition, will last another 10+ years. If your dryer sounds like a freight train when it runs, more than likely the support rollers (which act as bearings) need to be replaced. Replace the dryers' belt and pulley while you're at it, since those components usually have the same life span, which is about 10 years. The motor should last the life of the dryer, sooner under heavy use or if there are electrical spikes or other electrical problems.
Proper maintenance, which basically amounts to keeping the exhaust and lint chute areas clean, and proper use will make your dryer last many years without a problem. Should you encounter a problem, it is always best to replace your dryer's components with OEM (Original Equipment Manufacturer) parts to ensure proper fit and a long-lasting, well-performing dryer.