What is the primary role of a pressure switch in a gas furnace?

The primary role of a pressure switch in a gas furnace is to shut down the system if safe operating conditions are not met. This component plays a critical safety role by monitoring the pressure within the venting system. If the pressure is too low or too high, indicating a potential blockage or other issues in the vent system, the pressure switch will trigger a shut down of the furnace. This prevents dangerous situations, such as the buildup of harmful gases inside the home or an explosion.

In properly functioning systems, the pressure switch ensures that the furnace operates only when there is adequate airflow and proper venting, which is essential for safely exhausting combustion gases. This safety feature is vital for maintaining safe operation in gas furnaces, thus protecting both the equipment and the occupants of the space where it's installed.