Controller for two-stage heat source usable with single and two stage thermostats
First Claim
1. A controller for a two-stage heat source, adapted to be connected to either a single stage or two-stage thermostat, the controller comprising:
- a first terminal configured for connection to the single-stage thermostat for receiving a signal requesting heat operation from the single-stage thermostat connected to the first terminal, or for connection to the two-stage thermostat for receiving a signal for first-stage heat from the two-stage thermostat connected to the first terminal;
a microcontroller in communication with the first terminal, the microcontroller being configured to calculate a duty cycle value based on a duration of time in which a heat signal is present at the first terminal relative to a duration of a heating cycle, and to determine a first stage time limit that is determined from the duty cycle, wherein the microcontroller is configured to control the operation of the two stage heat source to provide first stage low heating operation while the first stage heat signal is present up to the first stage time limit, and to provide second stage heating when the first stage heat signal is present beyond the first stage time limit period.
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Accused Products
Abstract
A controller for a two-stage heat source is provide, which may be connected to either a single stage or a two-stage thermostat to provide low stage heating for a variable time period before switching to high stage heating. The controller includes at least a first terminal for receiving a signal requesting heating from a single-stage thermostat or a two-stage thermostat connected to the first terminal. A microcontroller in communication with the first terminal determines a duty cycle value for a heating cycle based on the duration in which a signal at the first terminal is present relative to the duration of the heating cycle. The microcontroller determines a low stage time limit from the duty cycle, and provides low stage heating when a signal is present at the first terminal for a time period not more than the time limit, and switches to high stage heating after the time limit.
56 Citations
20 Claims
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1. A controller for a two-stage heat source, adapted to be connected to either a single stage or two-stage thermostat, the controller comprising:
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a first terminal configured for connection to the single-stage thermostat for receiving a signal requesting heat operation from the single-stage thermostat connected to the first terminal, or for connection to the two-stage thermostat for receiving a signal for first-stage heat from the two-stage thermostat connected to the first terminal; a microcontroller in communication with the first terminal, the microcontroller being configured to calculate a duty cycle value based on a duration of time in which a heat signal is present at the first terminal relative to a duration of a heating cycle, and to determine a first stage time limit that is determined from the duty cycle, wherein the microcontroller is configured to control the operation of the two stage heat source to provide first stage low heating operation while the first stage heat signal is present up to the first stage time limit, and to provide second stage heating when the first stage heat signal is present beyond the first stage time limit period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A controller for a two-stage heat source, adapted to be connected to either a single stage or two-stage thermostat, the controller comprising:
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a first terminal configured for connection to the single-stage thermostat for receiving a signal requesting heating from the single-stage thermostat connected to the first terminal, or for connection to the two-stage thermostat for receiving a signal requesting low-stage heating from the two-stage thermostat connected to the first terminal; a second terminal for receiving a signal requesting high-stage heat operation from the two-stage thermostat connected to the second terminal; a microcontroller in communication with the first and second terminals, the microcontroller being configured to determine a duty cycle value for one or more heating cycles based on the duration of time in which the heat signal at the first terminal is present relative to the duration of the heating cycle, and to select a low stage time limit from a number of low stage time limits corresponding to a number of duty cycle values from a look-up table in a memory of the microcontroller, wherein the microcontroller is configured to control the operation of the two stage heat source to provide low stage the low stage heating operation when the heat signal is present at the first terminal up to the low stage time limit determined from the duty cycle valve, and to provide the high stage heating operation while the heat signal is present at the first terminal beyond the low stage time limit; and wherein the microcontroller controls the operation of the two stage heat source to provide the second stage heating whenever the heat signal requesting the second stage heat operation is present at the second terminal. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method for controlling the operation of a two stage furnace comprising:
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determining whether a request signal for heat operation is present at a first terminal; calculating at least one duty cycle value based on a duration of time in which the request signal was present at the first terminal in a previous heating cycle relative to the total duration of the previous heating cycle; determining a low stage time limit value from the at least one calculated duty cycle value; providing for low stage low-heating operation as long as a signal is present at the first terminal until the low stage time limit is reached; providing for high stage high-heating operation after the low stage time limit has been reached, as long as the signal at the first terminal remains present; and discontinuing all heating operation when the signal at the first terminal is no longer present. - View Dependent Claims (17, 18)
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19. A method for controlling the operation of a two-stage heating system, the method comprising the steps of:
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actuating low stage heating operation upon detecting a request signal for heat operation at a first terminal; calculating at least one duty cycle value based on a duration of time in which the request signal was present at the first terminal in a previous heating cycle relative to the total duration of the previous heating cycle; determining a low stage time limit value from the at least one calculated duty cycle value; initiating a low stage timer means that is set to the low stage time limit; continuing the low stage low-heating operation as long as a signal is present at the first terminal until the low stage time limit expires; activating high stage high-heating operation after the timer has expired; continuing the high stage high-heating operation as long as a signal is present at the first terminal after the expiration of the timer; and discontinuing all heating operation when the signal at the first terminal is no longer present. - View Dependent Claims (20)
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Specification