초록 ▼

A furnace control apparatus for a downflow forced warm air furnace uses a microprocessor and thermostat to initiate and control the start-up of the furnace. During the initial start-up operation, the microprocessor receives an input signal from the thermostat indicative of the need for a furnace ope

A furnace control apparatus for a downflow forced warm air furnace uses a microprocessor and thermostat to initiate and control the start-up of the furnace. During the initial start-up operation, the microprocessor receives an input signal from the thermostat indicative of the need for a furnace operation and produces an output signal for controlling, in combination with the thermostat which responds to the temperature of the space to be heated, an actuation of a gas valve to supply gas to the furnace. Subsequently, an analog temperature sensor in an air supply duct is used to supply another input signal through an analog-to-digital converter to the microprocessor representative of the air temperature in the duct. The microprocessor stores the value of the air temperature following the start-up of the burner and subsequently turns on an air circulator. Following the energization of the air circulator, the microprocessor determines via a fixed logic sequence whether the delivered air temperature rises a minimum amount above the stored initial temperature after a preset time period as an indication of a circulator failure. Additionally, the analog temperature sensor is used by the microprocessor to determine if the delivered air temperature ultimately rises above a predetermined high or maximum limit an an indication of a restriction in an air return duct. In either case of the delivered air temperature not meeting aforesaid criteria, the microprocessor deactuates the gas valve to interrupt the flow of gas to the burner to protect the heating system.

대표청구항 ▼

A furnace control apparatus comprising fuel combustion means for heating a heating medium, a furnace fuel supply valve arranged to supply fuel to said combustion means, valve control means for controlling the actuation of said valve to control the flow of fuel therethrough, circulator means for supp

A furnace control apparatus comprising fuel combustion means for heating a heating medium, a furnace fuel supply valve arranged to supply fuel to said combustion means, valve control means for controlling the actuation of said valve to control the flow of fuel therethrough, circulator means for supplying the heating medium from the furnace after heating by said combustion means by inducing a flow of the heating medium counter to a temperature induced flow of the heating medium produced by said combustion means, temperature measuring means for sensing the temperature of the heating medium supplied from the furnace by said circulator means and producing an output signal representative of the sensed temperature and logic means responsive to an energization of the circulator means and the output signal from the temperature measuring means for controlling said valve control means initially to admit fuel to said combustion means during a start-up of the furnace and subsequently to interrupt the flow of fuel through said valve when the temperature of the heating medium fails to reach a first reference temperature after a predetermined time period following the energization of the circulator means.