What is the purpose of a pressure switch on a non-condensing furnace?

The purpose of a pressure switch on a non-condensing furnace is to prove the operation of the induced-draft blower. This component is crucial for ensuring that there is sufficient airflow within the system before the furnace begins the ignition sequence. The pressure switch monitors the pressure in the venting system; if the induced-draft blower is functioning properly and creating the necessary negative pressure, the switch will close. This closure allows the ignition process to proceed, confirming that the blower is effectively removing combustion gases and aiding in the safe operation of the furnace.

Understanding this role highlights the importance of the induced-draft blower in maintaining efficiency and safety, as it ensures that harmful gases are vented properly, thus preventing potentially dangerous situations. The proper functioning of the pressure switch is critical to the overall operation of the furnace, as it acts as a safety mechanism to prevent the appliance from operating under unsafe conditions.