At what voltage does a spark igniter typically operate?

The spark igniter used in gas furnaces typically operates at 10,000 volts of alternating current (VAC). This high voltage is essential for generating a sufficient spark to ignite the gas. When the igniter produces a spark at this voltage, it creates a reliable ignition source for the combustion process in the furnace.

Operating at this level ensures that the spark can effectively penetrate any ambient gas mixture, facilitating a quick and reliable ignition while also helping to prevent any unburned fuel from accumulating, which could pose safety risks. The choice of 10,000 VAC is a commonly accepted standard in the industry, balancing performance and reliability without escalating too high and creating unnecessary complexity or risk.

In contrast, voltages higher than this, such as 15,000 VAC or 20,000 VAC, while potentially effective, would not be typical for spark igniters in residential gas furnaces due to increased safety concerns and the likelihood of causing overheating or premature wear on the igniter components. Thus, the operating voltage of 10,000 VAC is both a practical and safe choice for this application.