Which component is essential for the ignition process in an oil-fired furnace?

The flame sensor plays a crucial role in the ignition process of an oil-fired furnace. Its primary function is to detect the presence of a flame once the burner has ignited. When the ignition sequence is initiated, fuel is atomized by the burner and ignited by an ignition source, typically an ignition electrode or transformer. The flame sensor monitors the flame to ensure that combustion is occurring correctly; if it does not detect a flame, it signals the control system to shut off the fuel supply, preventing the buildup of unburned oil, which can lead to dangerous conditions such as oil leaks or explosions.

This component ensures safe operation by providing feedback that allows the furnace to operate or shut down as needed based on whether a flame is present, thus preventing potential hazards. While the blower motor helps circulate air, the oil pump supplies fuel to the burner, and the fuel filter ensures clean oil delivery, none of these components are directly involved in the ignition verification process, making the flame sensor essential for safe and effective operation.