Abstract: An economizer controller calibration method, comprising: sealing an economizer perimeter gap between the economizer frame and a Heating, Ventilating Air Conditioning (HVAC) system cabinet to reduce an uncontrolled outdoor airflow; determining a functional relationship between an economizer actuator voltage (x) and a damper position Outdoor Airflow Fraction (OAF) (y); monitoring the economizer actuator voltage (x) and measuring at least one airflow characteristic to calculate the damper position OAF (y) and obtain a set of x-versus-y data for at least two damper positions: closed, intermediate, and fully-open; calculating at least two coefficients of the functional relationship using the x-versus-y data; calculating a target economizer actuator voltage (xt) as a function of a required OAFr (yr) using the functional relationship; and positioning the damper using the target economizer actuator voltage (xt) to provide the target damper position OAFr (yr) within a tolerance of the required OAFr (yr).

Abstract: A method for sealing an economizer perimeter gap to reduce an uncontrolled excess outdoor airflow by applying a sealing material over or into the economizer perimeter gap between the economizer frame and a Heating, Ventilating, Air Conditioning (HVAC) system cabinet comprising: locating the economizer perimeter gap between the economizer frame and the HVAC system cabinet and applying a sealing material over or into the economizer perimeter gap. The sealing material is selected from the group consisting of: an adhesive tape sealant, an adhesive sealant, a mastic sealant, a caulking material, and a weatherstripping. The method comprises: disconnecting an electrical power to the HVAC system, removing an economizer hood, locating and cleaning the metal services on both sides of the gap between the economizer frame and the HVAC cabinet, applying the sealing material over or into the gap, reinstalling the economizer hood, and reconnecting the electrical power to the HVAC system.

Abstract: A Fault Detection Diagnostic (FDD) variable differential and variable fan-off delay Heating Ventilating Air Conditioning (HVAC) thermostat control method. The FDD method detects a fan-on setting, reports a FDD fan-on alarm, overrides a fan-on setting, and turns off an HVAC fan. The FDD method detects, reports, and corrects a short-cycle by providing a variable differential based on: a cooling or heating cycle duration, or an off-cycle time. The variable fan-off delay is based on: a Conditioned Space Temperature (CST), comparing a current CST to the CST measured during the fan-off delay, a rate of change of CST with respect to time (dT/dt), dT/dt reaches an inflection point, the CST crosses a fan-off-delay differential, a cooling cycle duration, a heating cycle duration, a cooling temperature split, a heating temperature rise, an outdoor air temperature, a supply air temperature, or the rate of change with respect to time of these HVAC parameters.

Abstract: An apparatus providing Fault Detection Diagnostics (FDD) for a Heating, Ventilating, Air Conditioning (HVAC) system comprising a permanent magnet attached to a movable damper and a magnetometer attached to a stationary frame to provide a magnetic field measurement of the permanent magnet. The apparatus converts the magnetic field measurement into a damper position measurement and determines a difference between the damper position measurement and a damper position actuator voltage command, and if the difference is greater than a damper actuator voltage tolerance, then the apparatus generates a FDD alarm signal. The apparatus calculates a com puted Outdoor Air Fraction (OAF) damper position based on a measured HVAC parameter, and if the difference between the computed OAF damper position and the OAF damper position command is greater than a damper position tolerance, then the apparatus generates a FDD alarm signal or an actuator voltage signal to correct the movable damper position.

Abstract: The efficient fan controller includes a microprocessor receiving at least one signal input from thermostat/equipment control terminals to control a fan relay to operate a system fan. The microprocessor monitors a thermostat call for cooling/heating duration and determines a variable fan-off delay based on the cooling/heating cycle duration, and at an end of a cooling/heating cycle energize the fan relay to operate the system fan for the variable fan-off delay. The fan controller avoids false thermostat activation signals and includes a common wire adapter to provide continuous power to a smart communicating thermostat and is configured to evaluate floating, zero, rectified, false positive and active input signals. The fan controller can be embodied on a forced-air-unit control board or thermostat. The fan controller installation methods ensure the system fan/blower operates at high speed for heating and cooling to improve thermal comfort, efficiency and satisfy the thermostat sooner to save energy.

Abstract: A solid-state adapter provides a common-wire functionality to an HVAC system including four wire connections between a thermostat and HVAC equipment The adapter may include an embodiment of an efficient fan controller to provide a fan-off delay based on the duration of a heating cycle or the duration of a cooling cycle where the duration includes at least one duration selected from the group consisting of: a heating on time, a heating off time, a cooling on time, and a cooling off time. The solid-state common-wire adapter uses a TRIAC, capacitor and load resistor to provide a small, low-cost and reliable electronic device which repurposes the existing wiring harness to add a common wire functionality where previously one did not exist.

Abstract: A method for providing a cooling or heating variable fan-off delay based on a Conditioned Space Temperature (CST) measured during a current variable fan-off delay period compared to CST values measured during the current variable fan-off delay period. The method may also include turning off a cooling or heating system and continuing to operate an HVAC fan until the CST reaches an Inflection Point (IP) where a rate of change of the CST with respect to time (dT/dt) equals zero plus or minus a confidence interval tolerance. The method may also include providing a cooling or heating variable differential (or offset) and/or variable fan-off delay based on the duration of the thermostat call for cooling or heating, an off cycle time, a cooling temperature split, a heating temperature rise, outdoor air temperature, supply air temperature or a rate of change with respect to time of any of these HVAC parameters.

Abstract: Apparatus and methods are disclosed for a variable differential variable delay thermostat. The variable differential is based on the duration of a thermostat call for cooling or the duration of a thermostat call for heating. The variable cooling fan-off delay is based on cooling system parameters including but not limited to the duration of the cooling cycle, duration of the thermostat call for cooling, conditioned space temperature, temperature split, thermostat temperature rate of change, or thermostat temperature reaching a minimum inflection point or crossing a fixed or variable thermostat differential or differential offset.

Abstract: Apparatus and methods for Fault Detection Diagnostics (FDD) for a Heating, Ventilating, Air Conditioning (HVAC) system with an economizer to detect: 1) air temperature or relative humidity sensors failed/faulted, 2) dampers not modulating, 3) excessive outdoor air, 4) economizing when should not, 5) not economizing when should and 6) inadequate outdoor air. Economizer damper position is measured using at least one inertial Micro-Electro-Mechanical System (MEMS) device: 1) magnetometer, 2) accelerometer, 3) IMU and 4) rotatiometer. The magnetometer detects damper position using a small permanent-magnet attached to a movable damper and a MEMS device attached to the economizer frame. The accelerometer and IMU detect damper position using a MEMS device attached to the damper, and the ratiometer detects angular damper position. The methods determine whether or not the HVAC economizer, sensors, actuator and outdoor air dampers are functioning properly.

Abstract: The efficient fan controller includes a microprocessor receiving at least one signal input from thermostat/equipment control terminals to control a fan relay to operate a system fan. The microprocessor monitors a thermostat call for cooling/heating duration and determines a variable fan-off delay based on the cooling/heating cycle duration, and at an end of a cooling/heating cycle energize the fan relay to operate the system fan for the variable fan-off delay. The fan controller avoids false thermostat activation signals and includes a common wire adapter to provide continuous power to a smart communicating thermostat and is configured to evaluate floating, zero, rectified, false positive and active input signals. The fan controller can be embodied on a forced-air-unit control board or thermostat. The fan controller installation methods ensure the system fan/blower operates at high speed for heating and cooling to improve thermal comfort, efficiency and satisfy the thermostat sooner to save energy.

Abstract: An apparatus and method for measuring or controlling the Outdoor Air Fraction (OAF) ratio through economizer or outdoor air dampers and cabinet to total system airflow and mixed-air humidity ratio and wetbulb temperature for HVAC equipment. An OAF exceeding the minimum regulatory requirements wastes energy and contributes to global warming. OAF is used to optimize economizer damper position either manually or automatically using an economizer Fault Detection Diagnostic controller and actuator to meet minimum outdoor airflow requirements.

Abstract: An efficient fan controller for Heating Ventilating Air Conditioning (HVAC) systems including at least one electrical signal input from thermostat or equipment control terminals with a microprocessor to control a switching device connected to a signal output to control a fan relay and operate a system fan. The microprocessor is configured to monitor a thermostat call for cooling/heating duration and determine a variable fan-off delay based on the cooling cycle or heating cycle duration, and at an end of a cooling/heating cycle energize the fan relay to operate the system fan for the variable fan-off delay. The fan controller can include a heat pump detection signal input and electrical signal inputs to connect to a thermostat heat terminal, heat pump reversing valve terminal, or compressor terminal. The fan controller can also include a normally-closed relay connected to the switching device to maintain continuity between the fan signal input and output.

Abstract: An apparatus and method for measuring or controlling the Outdoor Air Fraction (OAF) ratio through economizer or outdoor air dampers and cabinet to total system airflow and mixed-air humidity ratio and wetbulb temperature for HVAC equipment. An OAF exceeding the minimum regulatory requirements wastes energy and contributes to global warming. OAF is used to optimize economizer damper position either manually or automatically using an economizer Fault Detection Diagnostic controller and actuator to meet minimum outdoor airflow requirements.

Abstract: A method for controlling heater ventilation fan operation increases fan speed from low to high after a short delay after turn-on, and continues fan operation for a period of time based on duration of operation, after turn-off. The higher fan speed improves heat transfer and efficiency while the heating system is operating. Continuing fan operation after turn-off maximizes recovery of additional heat from the heat exchanger. Known methods do not provide sufficient air flow to efficiently transfer heat from the heat exchanger to the air, and leave high temperature air (i.e., 110 to 200° F.) in the heat exchanger after turn-off.

Abstract: Apparatus and methods are disclosed for controlling a cooling ventilation fan after the thermostat call for cooling has ended by providing a variable fan-off delay time based on cooling system parameters including but not limited to the cooling system operating time, duration of the thermostat call for cooling, relative humidity, temperature split, thermostat temperature rate of change, or thermostat temperature reaching a minimum inflection point or crossing a fixed or variable thermostat differential or differential offset.

Abstract: Method for controlling an HVAC ventilation fan in heating or cooling mode and varying the fan-off time delay as a function of heat source or cool source operational time. Method for increasing heater ventilation fan speed from the low speed used for heating to the high speed used for cooling. Method for maintaining the heat pump reversing valve signal at the same position throughout the cool or heat source operational and extended variable fan-off time delay. Method for closing economizer dampers at the end of the cool or heat source operational time while continuing to operate the ventilation fan for an extended variable fan-off time delay.

Abstract: Method for controlling an HVAC ventilation fan in heating or cooling mode and varying the fan-off time delay as a function of heat source or cool source operational time. Method for increasing heater ventilation fan speed from the low speed used for heating to the high speed used for cooling. Method for maintaining the heat pump reversing valve signal at the same position throughout the cool or heat source operational and extended variable fan-off time delay. Method for closing economizer dampers at the end of the cool or heat source operational time while continuing to operate the ventilation fan for an extended variable fan-off time delay.

Abstract: Apparatus and methods are disclosed for a fan controller. The fan controller determines HVAC system type and heating or cooling mode for gas furnace, heat pump, electric resistance, and hydronic heating, ventilating, and air conditioning (HVAC) systems. For gas furnace heating systems, the apparatus and methods include energizing the blower fan from a lower fan speed used for heating by the furnace-fan controller to the high-speed used for cooling by the fan controller after fan-on delay time P1 to increase delivered heating capacity, satisfy the thermostat sooner and save heating energy. For heat pump, electric resistance, and hydronic heating systems the apparatus and methods include energizing the fan relay after a short fan-on delay time P0 based on previous off-cycle duration P11. For all these HVAC systems, the apparatus and methods vary extended fan-off time delay P2 as a function of cool-source operational time P4 or heat-source operational time P3.

Abstract: Apparatus and methods for efficient HVAC fan control. The apparatus includes an efficient fan controller for direct-expansion air conditioning and gas furnace, heat pump, electric resistance, and hydronic heating systems. For gas furnace heating systems, the apparatus and methods include energizing the heater ventilation fan from the low speed used for heating to the high speed used for cooling after time period P1 to deliver more heating output to satisfy the thermostat sooner and save heat source energy. For heat pump, electric resistance, and hydronic heating systems the apparatus and methods include energizing the fan relay after a short fan-on time delay P0 based on the previous HVAC system off-cycle time P11. For all of these HVAC systems, the apparatus and methods vary the extended fan-off time delay P2 based on air conditioning compressor or heat source operational time P3.

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.