Postpurge pilot burner sequencing means

Claim 1

A fuel burner sequencing means for controlling a fuel burner in response to a controller and which includes a pilot burner that is temporarily kept burning after a main burner is turned off thereby insuring complete combustion of fuel, including: motor operated cam controlled switch means and relay operated switch means; flame sensor and amplifier means controlling a portion of said relay operated switch means in response to a flame at said burners; said sequencing means responsive to said controller to provide a prepurge and a normal fuel burner ignition cycle to establish a flame at said main burner with said flame monitored by said flame sensor and amplifier means; said sequencing means including safety lockout means operable to stop said sequencing means and turn off fuel to said burners in the event said flame sensor and amplifier means fails to sense a flame at said burners; and said sequencing means further responsive to a termination sequence of operation of said fuel burner to initiate a postpurge pilot mode of operation whereby said pilot burner is provided with fuel prior to the termination of a flame at said main burner and wherein said pilot burner is ignited by said main burner; said flame sensor and amplifier means continuing to monitor said pilot burner during said postpurge pilot mode of operation without allowing said safety lockout means to stop said sequencing means while said pilot burner burns off any residual fuel from said main burner; said pilot burner being deenergized by said cam controlled switch means and said relay operated switch means to prepare the fuel burner for a subsequent cycle.