Patent ID: 9500366
Filing Date: 2016-11-22
CPC Classification: F23N,F23Q,F24D,F27B,G05B

Claim Text:
1. In a fuel-fed furnace of the type which comprises a burner supplied with fuel and which produces a flame; a heat exchanger in which the flame passes through a combustion air path of a heat exchanger to an exhaust; a blower which forces a flow or return air from a comfort space through a comfort air path of said heat exchanger, and thence through a ductwork to supply heated air to said comfort space; a source of AC power; a controller circuit coupled to said source of AC power and which controllably actuates said burner and said blower to effect a turn-on sequence in response to a call for heat from an associated thermostat, and to effect a shut down sequence when said call for heat is satisfied, said controller circuit including a microcontroller having a plurality of input ports and a plurality of output ports including ports to issue control signals for actuation of said burner and for said blower, said controller circuit further including a non-volatile memory device coupled with said microcontroller and operative to store a fault indication when present; at least one temperature actuated limit switch effective to commence said shut-down sequence when the temperature of said heat exchanger exceeds a predetermined limit temperature, and which resets to permit said turn-on sequence after said shut-down sequence; the improvement wherein