6.3 Gas Dryer Igniter and Gas Valve System Troubleshooting

Gas dryer igniter failure accounts for approximately 70% of gas dryer heating problems, making it the most common repair needed. The igniter serves dual functions: it heats up to ignite the gas and acts as a safety switch to open the gas valve only when hot enough to ensure reliable ignition. Understanding igniter operation and testing procedures can help homeowners diagnose and repair this common problem.

Two main igniter types exist in modern gas dryers: glow bar igniters (most common) and spark igniters (less common). Glow bar igniters are ceramic-based resistance devices that glow orange-hot when energized, similar to electric oven igniters. They draw 3.2-3.6 amperes when functioning properly and operate at temperatures around 1800°F. Spark igniters use high-voltage electrical discharge to ignite gas, similar to gas grill igniters.

Glow bar igniter failure typically occurs gradually due to thermal cycling stress. The ceramic material becomes brittle over time, developing microscopic cracks that increase electrical resistance. As resistance increases, the igniter draws less current, eventually insufficient to open the gas valve safety circuit. This results in the igniter glowing but no gas ignition, leaving clothes damp after full cycle completion.

Diagnosing igniter problems involves visual observation during dryer operation. With the dryer door open and machine running on a heated setting, observe the igniter through the drum opening (use a flashlight if necessary). A working igniter should glow bright orange within 30-90 seconds of heat demand. If the igniter glows dimly, doesn't glow at all, or glows brightly but no flame appears after 2-3 minutes, replacement is needed.

Testing igniter current draw provides definitive diagnosis but requires an ammeter and electrical knowledge. A failing igniter may glow but draw insufficient current (less than 3.0 amperes) to open the gas valve. This intermediate failure condition explains why some igniters appear functional but don't produce gas ignition.

Gas valve problems are less common but can occur due to electrical failure or mechanical sticking. The gas valve receives a signal from the control board when the igniter reaches proper temperature, typically measured by current draw through the igniter circuit. Valve replacement requires gas line disconnection and should be performed by qualified technicians due to safety considerations.

Safety precautions for gas dryer repair include proper ventilation, gas leak detection using soap solution on connections, and ensuring proper igniter-to-gas valve timing to prevent gas accumulation. Never attempt repairs if you smell gas or are uncomfortable working with gas appliances.