The pressure rating is -0.20" W.C PF. It has two wiring terminals and two hose ports. An air switch is safety designed to ensure that your inducer motor is running at the proper RPM, and creating the proper vacuum for your furnace to flue safely.
LF31 differential air pressure switch provides pressure, vacuum and differential pressure. Models capable of sensing very low set points, designed for the HVAC industry, where reliable air Proof is critical to performance and customers Safety. LF31 Furnace Pressure Switch is the favorite of leading manufacturers Gas heater and water heater.