You place the clothing in your gas dryer, add a dryer sheet to eliminate static cling, set the timer for 60 minutes, and press the start button. The drum immediately starts rotating so you get back to those other household chores that need to get done or back to that book you can’t wait to read the next chapter of. However, when you return to the laundry room an hour later and open the dryer door, you find the clothes are still wet. Obviously, the dryer is not heating. Why is the dryer not heating? The number one most common reason for a gas dryer failing to heat is a faulty gas valve solenoid coil or coils.
How do the solenoid coils help heat a gas dryer and how can you tell if a coil is defective? In this article, Repair Clinic will answer both questions.
How solenoid coils help heat a gas dryer
Unlike an electric dryer which uses an electrically-powered heating element to heat the air being circulated through the dryer drum, a gas dryer uses a burner assembly to heat the air.
The burner assembly consists of an igniter, gas valve solenoid coils, and a burner tube
A gas dryer burner assembly consists of an igniter, gas valve solenoids, and a burner tube to heat the air that dries the laundry tumbling in the rotating drum. The burner assembly is energized by a standard 120 volts of alternating current when the timer and heat setting are selected on the dryer control panel and the start switch is activated. The voltage passes through a cycling thermostat, a high-limit thermostat, and a thermal fuse, if applicable to the model, on its way to the burner assembly.
The solenoid coils activate plungers in the gas valve to allow gas to flow into the burner housing
Once it reaches the burner assembly, the voltage travels through a flame sensor and an initial gas valve coil before reaching the igniter. The igniter will begin to glow, and when it gets hot enough, the flame sensor will detect the heat and switch off, which diverts the current to the other gas valve coils. The coils then activate plungers in the gas valve which allows gas to flow out into the burner housing. Since this happens very quickly, the igniter is still hot enough to ignite the gas into a flame to heat the air being drawn through the dryer drum.
A cycling thermostat monitors the dryer air temperature
To maintain the proper air temperature during a drying cycle, the heat level in the blower housing is monitored by the cycling thermostat. During normal operation, the air temperature should be between 120 and 160 degrees Fahrenheit. When the air reaches the proper temperature for your dryer, the contacts in the cycling thermostat will open which switches off the voltage to the burner assembly. When the air temperature begins to cool, the contacts in the cycling thermostat will close. This allows voltage to once again travel to the solenoid coils and the other burner assembly components to reignite the gas supply to heat the air.
Solenoid coils can fail several minutes into the drying cycle
A common problem with gas valve solenoid coils is, that as they grow weaker, they may only work intermittently. While the coils may allow gas to flow into the burner housing to be ignited when the dryer is first started, they can fail several minutes into the drying cycle. This results in the dryer losing its ability to heat after the first three or four minutes or taking too long to dry the laundry.
Observe the burner assembly while the drying is running
Some gas dryers will have a small cover near the bottom of the cabinet that can be removed to reveal a peephole. You can look through the peephole when the dryer is running to observe the burner assembly. Alternatively, you can remove the appliance’s front panel and door, or a lower access panel, to view the burner assembly. If, at any time during the drying cycle, you observe the igniter glowing and then shutting off without establishing a flame, then one or more of the solenoid coils are probably defective and will need to be replaced. You can also use an ohm meter to test each solenoid coil for electrical continuity – a continuous electrical path present in the coil – to help determine if the part is faulty.
Testing a gas dryer solenoid coil
You can use either an analog ohm meter or a digital ohm meter to test a gas dryer solenoid coil. When using an analog meter, first rotate the range selection dial to 1K, or 1,000, ohms of resistance, then calibrate the meter by pinching the metal leads together while adjusting the needle to read “zero”. When using a digital meter, rotate the range selection dial to 2,000 ohms of resistance.
Ten steps to follow to test the gas valve solenoid coils
Now here are the 10 steps you can follow to test the gas valve solenoid coils:
- Unplug the dryer’s power cord to prevent electrical shock as you disassemble the appliance.
- Remove the dryer’s front panel and door or the lower access panel to reach the burner assembly. You will need to unthread some screws to detach any panels. To remove full front panels, you will probably need to detach the dryer’s top panel and, if applicable to the model, the control panel.
- For better access to the solenoid coils you may need to remove the drum. You can do this by pushing on the idler pulley to release the tension on the drum belt then unthread the belt from the idler pulley and motor pulley. You can use the belt to help lift out the drum.
- Detach the wire connector from the solenoid coil you’re testing. The coils will be located on the gas valve. It’s a good idea to isolate each coil from the appliance by unthreading the mounting screw securing the coil so you uninstall the part and set it on a table.
- Gas valve solenoid coils will have two terminals or three terminals. When testing a two-terminal coil, contact the black meter lead to one of the terminals and the red lead to the other terminal.
- Observe the meter display. The display should indicate that the two-terminal solenoid coil has a resistance between 1,000 and 2,000 ohms if it is functioning normally. Be aware, that you may need to experiment with resistance settings to detect electrical continuity.
- When testing a three-terminal solenoid, contact the black meter lead to Terminal 1, which is the common terminal, and the red lead to the second terminal.
- Observe the meter display. The three-terminal coil should indicate a resistance between 300 and 2,000 ohms.
- Keeping the black lead on the common terminal, move the red lead to contact the third terminal.
- Observe the meter display. Again, the three-terminal coil should indicate a resistance between 300 and 2,000 ohms if the coil is functioning normally.
What do the test results mean?
If any of the gas valve solenoid coils fall below the expected ohms of resistance range, you can be pretty certain that the component is faulty and should be replaced. A good practice to follow is to replace all the coils at the same time. Still, testing alone can be inconclusive, so it’s best to combine solenoid coil testing with actual observation of the burner assembly when the dryer is running. While the failure of the solenoid coils is the number one reason a burner assembly won’t work, it’s not the only reason. If you’ve installed new coils, but the igniter still glows and shuts off without establishing a flame, then the gas valve is likely defective and will need to be replaced.
Free repair guidance to fix a broken dryer
Looking for step-by-step guidance on how to replace the gas valve solenoid coils on a model WGD49STBW2 Whirlpool Gas Dryer? Or the right way to install a new igniter on a model GRDN510GM1WS GE Gas Dryer? Repair Clinic’s “Videos & Articles” section provides free repair information to help you fix your broken dryer quickly and successfully. To find the right procedural video, step-by-step guide, or dryer schematic, enter the full model number of your appliance in the search bar.
When replacing a gas valve solenoid coil set, a gas valve assembly, an igniter, or any other dryer component, Repair Clinic believes you should be using genuine original equipment manufacturer (OEM) replacement parts. Genuine manufacturer parts from top brands such as Bosch, Electrolux, GE, Kenmore, LG, Maytag, Samsung, Speed Queen, and Whirlpool are specifically designed to work with the models they’re installed in, and can be more compatible and longer-lasting than a generic part. To find a comprehensive list of parts fully compatible with your dryer, enter the dryer model number in the Repair Clinic search bar. With Repair Clinic as your repair partner, doing it yourself has never been easier.