LEFOO LF31 air Furnace Differential Pressure Switch Pressure 100pa used in heating ventilation refrigeration cooling heater Pressure fall 0.4"WC; Two Ports. Contact Arrangement: SPDT; Connection:6.4mm for tube connection. Operating temperature: 0 to 85. Mounting position: diaphragm in any vertical plane; With L bracket. Media: air, products of combustion or natural gas.