Furnace service. The customer has an addition that was put on this house some years ago, and they added a second-floor ductwork in the crawl space. There is a duct blower motor attached to the ductwork to help push and supply air to the second-floor addition area. The blower motor is timed with the primary furnace blower motor, and they both turn on at the same time. However, the secondary duct blower motor has an eight-minute time delay before it shuts off. The homeowner thought the blower motor was running constantly, but it shuts off on its own, leaving about an eight-minute window before the furnace wants to call for heat again. Therefore, turning both blower motors back on System is heating properly as it should, and both blower motors work properly and shut off on their own as they should.