Katonah Fire Department kicked off the month of October with a night time residential alarm that was quickly upgraded. At about 7:45 p.m. Tuesday night, Katonah Fire Department was dispatched to a residential alarm at a large house on Cantitoe Street. Car 2211, Car 2213, Engine 116, Ladder 39 and Tanker 6 responded. Once on scene, and after discovering a smoke condition on the home's upper floors, Car 2211 upgraded the alarm, resulting in Engine 110 from Bedford Village responding to the scene, along with Mount Kisco Fire Department's FAST team. At the same time, Bedford Hills Fire Department was asked to put a ladder and an engine on stand by in their quarters. A thorough search of the home's three floors and basement was completed and the cause of the smoke was attributed to a faulty air handler. Fortunately, no fire was discovered. Units were operating for approximately an hour.