Control circuit for a forced-air heating system
First Claim
1. A control circuit for a heating system having a furnace, a plenum defining an interior space which is in heat exchange relationship with the furnace, and an electrically-driven blower for establishing a flow of air through the plenum, the control circuit comprising:
- a sensor device that is positionable in thermally-conductive relationship with the interior space of the plenum for sensing the temperature in the plenum,means for controlling the operating speed of the blower in response to the temperature sensed by the sensor device, anda display device for providing a visually-discernible display of the operating speed of the blower.
1 Assignment
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Accused Products
Abstract
A control circuit for a forced-air heating system comprises a silicon diode that is positionable in thermally-conductive relationship with the interior space of a furnace plenum. A current source supplies current to the silicon diode, and the potential drop across the silicon diode is sensed. The operating speed of the blower is controlled in response to the voltage drop across the silicon diode in a manner such that when the temperature in the plenum is below a first level, the blower is not driven; when the temperature reaches the first level, the blower is driven at a first speed; and when the temperature reaches a second level, which is higher than the first level, the blower is driven at a second speed, which is higher than the first speed.
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Citations
27 Claims
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1. A control circuit for a heating system having a furnace, a plenum defining an interior space which is in heat exchange relationship with the furnace, and an electrically-driven blower for establishing a flow of air through the plenum, the control circuit comprising:
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a sensor device that is positionable in thermally-conductive relationship with the interior space of the plenum for sensing the temperature in the plenum, means for controlling the operating speed of the blower in response to the temperature sensed by the sensor device, and a display device for providing a visually-discernible display of the operating speed of the blower. - View Dependent Claims (2, 3, 4, 5)
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6. A control circuit for a heating system having a furnace, a plenum defining an interior space which is in heat exchange relationship with the furnace, and an electrically-driven blower for establishing a flow of air through the plenum, the control circuit comprising:
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a sensor device that is positionable in thermally-conductive relationship with the interior space of the plenum, the sensor device being operative to develop a voltage signal that depends on the temperature of the sensor device, a first amplifier connected to receive said voltage signal, the first amplifier having at least one input terminal connected to the sensor device and having an output terminal, and means for controlling the operating speed of the blower, comprising a Schmitt trigger circuit having an output terminal and also having an input terminal connected to the output terminal of the first amplifier, a differential amplifier having an output terminal, a first input terminal connected to the output terminal of the Schmitt trigger circuit, and a second input terminal connected to the sensor device, and a blower speed control circuit connected to the output terminal of the differential amplifier. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A control circuit for a heating system having a furnace with an electrically-driven draft inducer, a plenum defining an interior space which is in heat exchange relationship with the furnace, and an electrically-driven blower for establishing a flow of air through the plenum, the control circuit comprising:
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a sensor device that is positionable in thermally-conductive relationship with the interior space of the plenum for sensing the temperature in the plenum, means for controlling the operating speed of the blower in response to the temperature sensed by the sensor device, and means responsive to the sensor device for providing a disable signal in the event that the temperature in the plenum reaches a predetermined level, the disable signal being operative to disable the draft inducer. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A control circuit for a heating system having a furnace with a solid fuel feed mechanism, a plenum defining an interior space which is in heat exchange relationship with the furnace, and an electrically-driven blower for establishing a flow of air through the plenum, the control circuit comprising:
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a sensor device that is positionable in thermally-conductive relationship with the interior space of the plenum for sensing the temperature in the plenum, means for controlling the operating speed of the blower in response to the temperature sensed by the sensor device, and means responsive to the sensor device for providing a disable signal in the event that the temperature in the plenum reaches a predetermined level, the disable signal being operative to disable the fuel feed mechanism. - View Dependent Claims (23, 24, 25, 26, 27)
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Specification