R.e. Phelon Company, Inc.

Richard D Newberry

Roger W Williams, Jr

Disclosed is an electronic control system for controlling the operation of an oil burner heating system. The control system comprises a relay circuit having first and second relays. When the relays are closed, an external power source is connected to an igniter and motor. The control system also comprises a relay contact monitor configured to detect whether the relays contacts are welded. The control system also comprises a relay control circuit adapted to energize the relays in response to the call for heat from the thermostat and a signal from the relay contact monitor indicative that the relay contacts are not welded. The relays are configured such that only one relay will open or close with power across its contacts. The control system further comprises an improved flame sense monitor adapted to quickly output signals indicative of flame or no flame when such conditions are present with sensitivity hysteresis and a feature to adjust such hysteresis.

System and method for controlling the operation of a primary burner

Electronic control system for an oil burner has a primary direct current power source controlled by a thermostat and a secondary direct current power source independent of the thermostat. A first relay is in circuit with the oil burner motor to energize the same and a second relay is in series with the first and with an alternating voltage source for energizing the ignitor of the furnace. An electronic circuit controls the first relay switch and includes a pair of silicon controlled rectifiers (SCR's) connected in series for energizing the first relay. A second electronic circuit includes a pair of interconnected NPN transistors for controlling the operation of the second relay switch. The first NPN transistor is conductive when the second relay switch is energized and the second NPN transistor is connected to the first to turn 'OFF' the same in response to flame being sensed in the furnace. A flame sensing element in the furnace is associated with a control relay for controlling a pair of relay switches, one of which is in series with the SCR's and the other is adapted to energize a redundant pair of time-delay circuits. Each time-delay circuit includes a capacitor and a programmable unijunction transistor (PUT) programmed to breakover at a voltage which is a function of a first predetermined time for charging a capacitor and a resistance in the cathode circuit of each PUT which provides for a second predetermined time for the discharge of the capacitor voltage to hold the second relay 'OPEN' by conduction through the second NPN transistor. Another electronic circuit includes an NPN transistor and PNP transistor connected to energize the first relay switch.

Growing community of inventors

Hadley, MA, United States of America

Richard D Newberry