Finding your clothing still damp after the dryer has run for sixty minutes may be the textbook definition of “disappointing”. Before you give up on the appliance in favor of stringing up a clothesline, you should know that there are specific replaceable dryer parts that can cause 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, and a burner tube to heat the air that dries the laundry tumbling in the rotating drum. Since good air flow is vital for the burner flame to be 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 from the wall. Is your dryer in 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 cut off power to the burner if the dryer overheats. You can use a multimeter to test the fuse for continuity – a continuous electrical path present in the part. If the fuse tests negative for continuity, it has blown and will need to be replaced.
- Defective gas valve solenoid coils – The solenoid coils open the gas valve, allowing gas to flow into the burner tube where it can be ignited by the igniter. A solenoid can fail several minutes into the drying process which will prevent the dryer from heating properly. If you observe the igniter glowing and then shutting off without a flame appearing then one or more of the solenoid coils is probably defective.
- Faulty igniter – Located right next to the burner tube, the igniter element should get hot enough to ignite the incoming gas. A faulty or weakened igniter will 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 allowing them to open the gas valve. The 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 is not in use, so if the component tests negative for continuity at room temperature, you know the part is defective.
- Failed thermostat – A high-limit thermostat, located on the burner assembly, monitors the dryer temperature and will shut off the burner if the dryer overheats. A cycling thermostat, normally located on the blower housing, will cycle the burner on-and-off to regulate the air temperature. If either of 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 failing to heat, however, are more unique:
- Burned-out heating element – Unlike the burner assembly on a gas dryer, an electric dryer use an electric heating element to warm the air before it enters the drum. If the element has burned-out or if any part of the element assembly is defective, the dryer will 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 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 can set the multimeter to “Volts AC” and test the electrical outlet to determine if 240 volts are present (keep in mind that readings can vary between 210 and 240 volts).
- Damaged power cord connection – The point where the dryer power 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 could be defective as well, although this isn’t a common problem. While the board can not 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 inside the exhaust venting. At least once a year you should detach the venting from 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 consider using 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 find the right matching part, enter the full model number of the appliance in the Repair Clinic website search bar, then use the part category and part title filters to home in on the exact part you need. While Repair Clinic carries dryer parts for all the top brands including Kenmore, GE, Whirlpool, Maytag, Electrolux, LG, and Samsung, you’ll want to make sure you’re selecting a part that is directly associated with your dryer model.