Abstract: A burner control apparatus for use with a furnace installation that has an operating control to produce a request for burner operation, a flame sensor to produce a signal when flame is present in the monitored combustion chamber, one or more devices for control of ignition and relay fuel flow, and a modulator controlling air and fuel flow to a main burner for varying heat output. The burner control apparatus comprises a lockout relay for shutting down the furnace, a control device for actuating the ignition and fuel control devices, and a timing circuit that provides several successive and partially overlapping timing intervals of precise relation, including a purge interval, a pilot ignition interval, and a main fuel ignition interval. The present invention includes circuitry for providing a purge interval with the modulator at a high air flow setting. After the purge interval, pilot flame ignition is prevented until the modulator has been moved to a low fire position.

Abstract: A burner control apparatus for use with a fuel installation that has an operating control to produce a request for burner operation, a flame sensor to produce a signal when flame is present in the monitored combustion chamber, and one or more devices for control of ignition and/or fuel flow. The burner control apparatus comprises lockout apparatus for de-energizing the control apparatus, a control device for actuating the ignition and/or fuel control devices, and a timing circuit that provides four successive and partially overlapping timing intervals of precise relation, including a purge timing interval, a pilot ignition interval, and a main fuel ignition interval. The present invention further includes a burner control system which verifies the proper operation of certain sensors in a burner or furnace including particularly the air flow sensor.

Abstract: This invention relates to control circuits of the type which continuously monitor their own performance so as to be self-checking, i.e., to produce a response whenever the system shows the absence of a condition being monitored or a change therein and also produces a response if the control system itself should become inoperative or otherwise malfunction.

Abstract: A system condition indicator for monitoring a number of interlock switches and fuel valves to detect what event first occurs to shut down a burner control system. The monitoring circuitry is periodically strobed once each cycle of the power line signal and is only responsive to an abnormal interlock switch or fuel valve during the strobe time. The present invention does not respond to an abnormal condition for a predetermined time after burner operation is initiated, to allow the system parameters to go to their operational values. The present invention includes circuitry for monitoring the pilot fuel flow and the main fuel flow and for providing an indication if either flow is abnormally terminated to shut down the furnace system. When the furnace system is shut down in response to an abnormal condition, an indication is provided of the first interlock switch or fuel valve to open, allowing a determination to be made of what caused the furnace failure, either during start-up or during normal operation.

Abstract: Burner control apparatus includes a control device for actuating an ignition control means, and a timing circuit for providing an ignition timing interval which extends beyond flame detection for a timed interval. The timing circuit is actuated in response to a request for burner operation and the control device is energized in response to the actuated timing circuit. The control device is maintained energized if a signal from the flame sensor is received before the end of the ignition timing interval, and the control device is deenergized and lockout circuitry is energized in the absence of a signal from the flame sensor. Main fuel supply is delayed for the timed interval to provide pilot flame stabilization.

Abstract: A burner control apparatus for use with a furnace installation that has an operating control to produce a request for burner operation, a flame sensor to produce a signal when flame is present in the monitored combustion chamber, and one or more devices for control of ignition and/or fuel flow. The burner control apparatus comprises lockout apparatus for de-energizing the control apparatus, a control device for actuating the ignition and/or fuel control devices, and a timing circuit that provides four successive and partially overlapping timing intervals of precise relation, including a purge timing interval, a pilot ignition interval, and a main fuel ignition interval. The present invention further includes a burner control system which verifies the proper operation of certain sensors in a burner or furnace including particularly the air flow sensor.

Abstract: Burner control apparatus includes control devices for actuating an ignition control means, and a timing circuit for providing an ignition timing sequence of four precise intervals. The timing circuit is actuated in response to a request for burner operation and the control devices are energized in sequence and combination in response to the actuated timing circuit. Time sequential pilot flame and main flame stabilization intervals are provided. If a signal from the flame sensor is received before the end of the overlapping flame stabilization timing intervals, the control device is energized and if flame detection signal is lost a lockout circuit is energized.

Abstract: Burner control apparatus includes a control device for actuating an ignition control means, and a timing circuit for providing an ignition timing interval of precise duration. The timing circuit is actuated in response to a request for burner operation and the control device is energized in response to the actuated timing circuit. The control device is maintained energized if a signal from the flame sensor is received before the end of the ignition timing interval, and the control device is deenergized and lockout circuitry is energized in the absence of a signal from the flame sensor.

Abstract: A precision lamp regulation circuit includes a source of AC power, a lamp connected in circuit with the AC source, a transistor switch connected in circuit between the AC source and the lamp, a light sensor optically coupled to respond to the radiation output of the lamp, circuitry for placing the transistor switch in conducting condition at the beginning of a half cycle of applied AC power, and a feedback circuit responsive to the light sensor for placing the transistor switch in non-conducting condition to terminate energization of the lamp during that half cycle of applied AC power.