External thermostat fan controller
First Claim
1. A method for efficiently controlling a heater ventilation fan, the method comprising:
- electrically connecting an external thermostat fan controller to thermostat leads of an existing HVAC system;
turning on a heat source in a heater;
turning on the heater ventilation fan to low speed;
waiting a first period of time P1;
switching the heater ventilation fan to high speed after the period of time P1;
running the heater for a period of time P3 until a selected temperature is reached;
turning off the heat source in the heater;
waiting a second period of time P2;
turning the heater ventilation fan off after the period of time P2.
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Accused Products
Abstract
A method for efficient control of a heater ventilation fan. The method includes switching the heater ventilation fan from low speed to high speed after a brief period P1 following starting, and continuing heater ventilation fan operation for a variable period of time P2 after the heat source has stopped. The period P1 is preferably about four minutes, and the period P2 is determined by the duration of heating and is generally between two and four minutes. Operating the heater ventilation fan at high speed improves heat transfer and efficiency while the heating system is operating, increases warm air movement to the space, satisfies the thermostat set point temperature in less time, reduces heating system operation, and reduces energy use. Continuing heater ventilation fan operation after turn-off maximizes recovery of additional heat from the heat exchanger to improve overall efficiency, extend the off cycle time, and save energy.
35 Citations
18 Claims
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1. A method for efficiently controlling a heater ventilation fan, the method comprising:
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electrically connecting an external thermostat fan controller to thermostat leads of an existing HVAC system; turning on a heat source in a heater; turning on the heater ventilation fan to low speed; waiting a first period of time P1; switching the heater ventilation fan to high speed after the period of time P1; running the heater for a period of time P3 until a selected temperature is reached; turning off the heat source in the heater; waiting a second period of time P2; turning the heater ventilation fan off after the period of time P2. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for efficiently controlling a heater ventilation fan, the method comprising:
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electrically connecting an external thermostat fan controller, including a trial as a switching device, to existing thermostat leads of an existing HVAC system, comprising the steps of; positioning the external thermostat fan controller; disconnecting a fan relay lead originally connecting a thermostat fan terminal to a fan relay controlling a fan, from the thermostat fan terminal; reconnecting the fan relay lead to a fan activation switch terminal of the external thermostat fan controller; connecting the thermostat fan terminal to a fan terminal on the external thermostat fan controller; leaving an original AC compressor lead in place between an AC compressor terminal of the thermostat and an AC compressor; and leaving a power signal lead in place between a transformer and the thermostat; turning on a heat source in a heater; turning on the heater ventilation fan to low speed; waiting a first period of time P1 of about four minutes; switching the heater ventilation fan to high speed after the period of time P1; running the heater for a period of time P3 until a selected temperature is reached; turning off the heat source in the heater; waiting a second period of time P2, wherein P2 is; zero minutes if P3 is less than four minutes; linearly increase from zero minutes to four minutes as P3 increases from four minutes to eight minutes; and four minutes if P3 is greater than eight minutes; and turning the heater ventilation fan off after the period of time P2.
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18. A method for efficiently controlling a heater ventilation fan, the method comprising:
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electrically connecting an external thermostat fan controller to existing thermostat leads of an existing HVAC system, wherein all of the power requirements of the external thermostat fan controller are provided though the existing thermostat leads; turning on a heat source in a heater; turning on the heater ventilation fan to low speed; waiting a first period of time P1 of about four minutes; switching the heater ventilation fan to high speed after the period of time P1; running the heater for a period of time P3 until a selected temperature is reached; turning off the heat source in the heater; waiting a second period of time P2, wherein P2 is; zero minutes if P3 is less than four minutes; two minutes if P3 is between four and five minutes; two and one half minutes if P3 is between five and six minutes; three minutes if P3 is between six and seven minutes; three and one half minutes if P3 is between seven and eight minutes; and four minutes if P3 is greater than eight minutes; and turning the heater ventilation fan off after the period of time P2.
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Specification