Which of the following components is NOT typically found in a high efficiency gas furnace?

In a high-efficiency gas furnace, the standard components are designed to maximize energy efficiency and improve safety during the ignition and heating processes. A standing pilot light is a continuously burning flame that remains lit to ignite the gas when the furnace calls for heat. However, in high-efficiency units, this component is not typically used.

Instead, high-efficiency gas furnaces often rely on hot surface igniters or direct spark igniters to ignite the gas, which eliminates the need for a constantly burning pilot light. These ignition systems are more energy-efficient because they consume gas only during the ignition cycle, thus eliminating the continuous gas consumption associated with a standing pilot.

Additionally, components such as combustion vacuum switches are utilized to ensure that there is proper venting and to prevent the furnace from operating if the venting system is obstructed, safeguarding the entire combustion process. This focus on efficiency and safety is a hallmark of high-efficiency furnaces, further illustrating why a standing pilot, commonly found in older or lower-efficiency models, is not included in their design.