What is the primary function of a fan control in a gas furnace?

The primary function of a fan control in a gas furnace is to start and stop the blower. This control is essential for managing the air circulation within the system and ensuring that heated air is distributed throughout the living space effectively. The blower draws in air from the return ducts, passes it over the heat exchanger where it is warmed, and then pushes the heated air back into the home. By controlling the operation of the blower, the fan control ensures that the furnace operates efficiently, maintaining comfortable temperature levels while also preventing overheating and promoting safety in the system.

Other functions, such as regulating fuel supply, monitoring temperature, or controlling air pressure, are managed by different components within the furnace. While those functions are critical to the overall operation of the furnace, they do not pertain specifically to the role of starting and stopping the blower, which is the primary responsibility of the fan control.