Learn how your appliance is supposed to operate so you can determine if it is malfunctioning.
Thirty years ago an open flame pilot light was used to ignite the flame in gas dryers. The resulting danger of igniting leaking gas and other negative features led to the use of vibrating contacts carrying an electric current. The sparks would ignite the gas to generate the desired flame. This method too had its disadvantages....ceasing to work when the contacts become charred and the sparks weren't hot enough to ignite the gas. With the advent of more durable metals, the modern glowing igniter was successfully developed and has become a very reliable and long-lasting method for igniting gas. It is also being used today in home gas furnaces to replace the pilot light.
The igniter is located on the end of the burner assembly and is positioned to be in the middle of the gas/air mixture (see figure below).
When the dryer control demands heat and the operating thermostat agrees the air temperature is too low, the ignitor is the first thing activated in the burner assembly. The ignitor gets red hot (over 2000 degrees Fahrenheit) and will ignite the gas when it is released. The ignitor (shown in the following circuit diagram) has a low resistance path as long as the radiant sensor is closed.
The radiant sensor is actually a thermostat located near the igniter. When the sensor heats up enough to open the circuit internally, current flows through the secondary coil and the igniter but the current is so low that the igniter starts to cool down. All coils are now energized and gas flows past the still hot igniter and bursts into a blue flame.
All of the information in these Appliance Clinic procedures is provided FREE OF CHARGE. No liability is assumed by the author for the accuracy of the contents or damages caused by the use of these procedures.