Instal draft hood on inducer motor causing to read carbon monoxide in attic and service side of the furnace clean evaporator coil in place, dirty coil causing high limit to trip and furnace is turning on and off Noticed there is a circuit board that was replaced and will recommend a surge protector for the furnace Evaporator coil and drain pan does not have float switch to prevent water damage in ceiling Will strongly advise to re install drain due to bad serviceability