Four-stage high efficiency furnace
First Claim
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1. A four-stage furnace comprising:
- a gas flow control assembly operable to provide gas to the furnace at one of four firing rates;
a heat exchanger;
an inducer blower for establishing a flow of combustion gases that generates a differential pressure across the heat exchanger; and
a furnace controller for controlling the rate at which the gas flow control assembly provides gas to the furnace and for controlling the inducer blower to establish one of four combustion gas flows that corresponds to one of the four firing rates.
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Abstract
A four-stage furnace includes a gas flow control assembly operable to provide gas to the furnace at one of four firing rates. The furnace also includes a heat exchanger and an inducer blower for establishing a flow of combustion gas that generates a differential pressure across the heat exchanger. A furnace controller controls the rate at which the gas flow control assembly provides gas to the furnace and controls the inducer blower to establish one of four combustion gas flows that corresponds to one of the four firing rates.
94 Citations
20 Claims
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1. A four-stage furnace comprising:
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a gas flow control assembly operable to provide gas to the furnace at one of four firing rates; a heat exchanger; an inducer blower for establishing a flow of combustion gases that generates a differential pressure across the heat exchanger; and a furnace controller for controlling the rate at which the gas flow control assembly provides gas to the furnace and for controlling the inducer blower to establish one of four combustion gas flows that corresponds to one of the four firing rates. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A four-stage furnace including an inducer blower for establishing a flow of combustion gas, a circulating air blower for establishing a flow of circulating air, and a heat exchanger, the furnace comprising:
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a gas flow control assembly for controlling a rate at which gas is supplied to the furnace to one of a first firing rate, a second firing rate, a third firing rate, and a fourth firing rate; a pressure switch assembly including a first pressure switch and a second pressure switch, wherein the pressure switch assembly senses differential pressure across the heat exchanger and generates pressure signals that vary in accordance with the differential pressure sensed across the heat exchanger; and a furnace controller for controlling the rate at which the gas flow control assembly supplies gas to the furnace, for controlling speeds of the inducer blower and the circulating air blower, and for receiving the differential pressure signals from the pressure switch assembly. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A furnace comprising:
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a main gas valve having low open state and a high open state; a throttling valve connected in fluidic series with the main gas valve and having a low open state and a high open state; and a furnace controller for operating the main gas valve and the throttling valve to supply a gas to the furnace at one of a low firing rate, a medium-low firing rate, a medium-high firing rate, and a high firing rate. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification