Finding your clothing still damp after the dryer has run for one hour may be the textbook definition of “disappointing”. Before you decide to give up on the appliance in favor of stringing up a clothesline, you should know that there are specific replaceable dryer parts that induce the dryer not to heat up. Troubleshooting why this happens will largely depend on whether the appliance is a gas or an electric model.
Top reasons for a gas dryer not heating
Gas dryers use a burner assembly consisting of an igniter, gas valve solenoids, along with a burner tube to heat the environment that dries the laundry tumbling in the rotating drum. Since good air flow is vital for the burner flame to become pulled through the burner housing properly, the dryer should be located in an open, well-ventilated area with the rear of the appliance kept several inches in the wall. Is your dryer inside a well-ventilated area with sufficient space left behind the rear panel? Good. We can now get down to the top reasons the appliance may fail to heat:
- Blown thermal fuse – The dryer thermal fuse, usually located on the blower housing and/or near the burner assembly, will blow and stop power to the burner when the dryer overheats. You can use a multimeter to test the fuse for continuity – a continuing electrical path present in the part. If the fuse tests negative for continuity, it's blown and will need to be replaced.
- Defective gas valve solenoid coils – The solenoid coils open the gas valve, allowing gas circulation into the burner tube where it may be ignited by the igniter. A solenoid can fail several minutes in to the drying process which will prevent the dryer from heating properly. Should you observe the igniter glowing and then shutting off without a flame appearing then one or more of the solenoid coils is most likely defective.
- Faulty igniter – Located next to the burner tube, the igniter element is deserving of hot enough to ignite the incoming gas. A faulty or weakened igniter is going to be unable to ignite the gas to heat the air. As with the thermal fuse, you can use a multimeter to test the igniter for continuity. If the igniter tests negative for continuity, it will need to be replaced.
- Malfunctioning flame sensor – The dryer flame sensor, located next to the igniter, is a bimetal component. The heat from the igniter will open the bimetal which increases the voltage to the solenoid coils letting them open the gas valve. Heat from the resulting flame will then keep the flame sensor circuit open. If the sensor malfunctions, the gas valve may not open. The bimetal should be closed, allowing for electrical continuity, when the dryer isn't in use, so if the component tests negative for continuity at 70 degrees, you know the part is defective.
- Failed thermostat – A high-limit thermostat, located on the burner assembly, monitors the dryer temperature and can shut off the burner if the dryer overheats. A cycling thermostat, normally on the blower housing, will cycle the burner on-and-off to manage the air temperature. If either from the thermostats fail, the dryer may not heat. Again, you can use a multimeter to test both thermostats for continuity.
What prevents an electric dryer from heating?
As with gas dryers, electric models require adequate space to allow for good air flow and they also have thermal fuses, high-limit thermostats, and cycling thermostats that can blow or fail. The other top causes of an electric dryer neglecting to heat, however, are more unique:
- Burned-out heating element – Unlike the burner assembly on a gas dryer, an electric dryer make use of an electric heating element to warm the environment before it enters the drum. If the element has burned-out or if any part of the element assembly is defective, the dryer is going to be unable to heat up. As with the thermal fuse and thermostats, you can use a multimeter to test the heating element for continuity. If the component tests negative, it will need to be replaced with a new one.
- Incoming power problem – While gas dryers only required 120 volts of alternating electric current to operate, most electric dryers require 240 volts running through two legs of voltage, each carrying 120 volts. If one leg of voltage is shut off by a tripped breaker or a blown fuse, the dryer may still be able to run, but it won't heat. You are able to set the multimeter to “Volts AC” and try out the electrical outlet to determine if 240 volts can be found (keep in mind that readings can vary between 210 and 240 volts).
- Damaged power cord connection – The point where the dryer cord terminals connect to the terminal block is a common location for electrical damage. If the terminals or the connection point appear burnt, you should replace the power cord, the terminal block, or both.
- Defective main control board – The dryer's main control board might be defective as well, although this is not a common problem. While the board cannot be easily tested, you can always inspect it for signs of burning or a shorted out component.
Make sure the venting is clear
Remember when we mentioned that the dryer can overheat and blow the thermal fuse? The number one cause of this is the build-up of lint within the exhaust venting. At least once annually you should detach the venting in the rear of the appliance and use a vent brush to clean out the lint and any other debris to ensure good air flow. You should also remember to clean out the dryer's lint filter after every cycle, and get a vacuum cleaner to periodically clean out the filter housing as well.
Find the right dryer parts with Repair Clinic
Repair Clinic stocks all the appliance replacement parts that can keep your gas or electric dryer heating properly, including igniters, gas valve solenoids, heating elements, thermal fuses, and cycling thermostats. To obtain the right matching part, go into the full model number of the appliance in the Repair Clinic website search bar, then make use of the part category and part title filters to home in on the exact part you'll need. While Repair Clinic carries dryer parts for all the top brands including Kenmore, GE, Whirlpool, Maytag, Electrolux, LG, and Samsung, you will want to make sure you're selecting a part that's directly associated with your dryer model.
