6.1 Understanding Electric vs Gas Dryer Heating Systems

Electric and gas dryers operate on fundamentally different heating principles, each with unique components and potential failure points. Electric dryers generate heat through resistance heating elements, similar to those found in electric ovens or space heaters. These elements consist of coiled wire housed in a metal sheath, typically located at the rear of the drum housing. When electricity flows through the element, resistance creates heat that's distributed throughout the drum by the circulation fan.

Gas dryers, conversely, use natural gas or propane combustion to generate heat. The heating system includes a gas burner assembly, igniter (either glow bar or spark igniter), gas valve, flame sensor, and exhaust system. When the dryer calls for heat, the igniter heats up to ignite the gas, creating a controlled flame that heats air circulating through the drum. This system is more complex but generally more energy-efficient than electric heating.

Both systems rely on similar control components including thermostats, thermal fuses, and control boards. The high-limit thermostat prevents overheating by cutting power to the heating system when temperatures exceed safe levels, typically around 200-220°F. The cycling thermostat maintains proper drying temperatures by turning the heat on and off as needed. The thermal fuse acts as a safety backup, permanently cutting power if extreme overheating occurs, usually indicating restricted airflow.

Understanding these fundamental differences is crucial for proper diagnosis. Electric dryer heating problems often involve element failure, thermostat malfunction, or electrical connection issues. Gas dryer problems more commonly involve igniter failure, gas valve issues, or flame sensor problems. Both types can suffer from lint buildup affecting airflow, which impacts heating efficiency and can cause safety component failures.

The diagnostic approach differs significantly between electric and gas systems. Electric dryers require multimeter testing of heating elements and electrical continuity checks. Gas dryers need visual inspection of igniter operation, flame characteristics, and proper gas flow. Safety considerations also vary, with electric dryers presenting shock hazards and gas dryers requiring attention to gas leaks and combustion safety.