The Lennox 14T66 Pressure Switch is an OEM combustion air pressure switch assembly designed for compatible Lennox 90% efficiency modulating gas furnaces, specifically downflow models. It monitors air pressure generated by the combustion inducer motor and signals the furnace control board when the required pressure conditions are met, allowing safe ignition and operation. Featuring a d... https://www.partshnc.com/14t66-lennox-pressure-switch