Abstract: A method and system for optimal model-based multivariable balancing for distributed hydronic networks based on global differential pressure/flow rate information. A simplified mathematical model of a hydronic system can be determined utilizing an analogy between hydronic systems and electrical circuits. Thereafter, unknown parameters can be identified utilizing the simplified mathematical model and a set of available measurements. Next, balancing valve settings can be calculated by reformulating the simplified mathematical model based on the parameterized model. The sum of pressure drops across selected balancing valves can be then minimized to achieve optimal economic performances of the system. The data can be collected and transferred to a central unit either by wireless communication or manually by reading the local measurement devices. Such a multivariable balancing approach provides a fast and accurate balancing of distributed hydronic heating systems based on a centralized and non-iterative approach.

Abstract: An HVAC controller with a simplified and/or lower cost user interface. In one illustrative embodiment, the HVAC controller includes two switches, a movable member, and a plurality of detents. The detents are configured to cause the two switches to be switched in a sequence when the movable member is moved. In some cases, a controller is coupled to the two switches, and may change an HVAC control parameter based on the switch sequence.

Abstract: A fault detection system and method for a warm air furnace is provided. A sensing circuit connected to an AC power source measures a level of current consumption during several points in the warm air furnace operating sequence. The measured level of current consumption is compared with an expected value. If the measured level exceeds the expected level by a threshold amount, a fault in the warm air furnace may be detected. An indication of at least one warm air furnace component that is most likely to have caused the fault may be provided.

Abstract: A controller equipped with a user interface having multiple-day programming capabilities, including methods of programming such devices, are disclosed. The user interface may include one or more menus or screens that can be used to program a schedule for one or more selected days during the week. An illustrative method of programming the controller may include the steps of entering a scheduling routine, selecting multiple days for schedule modification, changing the schedule parameters for one or more periods during the selected days, and then exiting the scheduling routine.

Abstract: Methods and devices for brushless DC motor operation. An example method may include using previously sensed Hall effect sensor transitions to predict a future Hall effect transition, and dividing a time between a most recent Hall effect sensor transition and the predicted Hall effect sensor transition into time increments. The time increments may be used to effect phase advance by selecting a number of time increments to create a time offset for phase advance purposes. The time increments may also be used as a virtual encoder. Devices incorporating controllers and control circuitry for performing like methods are also discussed.

Abstract: A deep format filter element has a peripheral frame with outwardly protruding mounting flanges. The mounting flanges simulate the periphery of a shallow format filter element to allow the deep format filter element to replace the shallow format filter element in many situations. The frame design allows the entire frame to be formed of cardboard and still provide adequate rigidity and strength. The frame includes at least a first cardboard sheet forming individual sides of the frame and panels of the mounting flange. The first cardboard sheet includes for each mounting flange at least two inside folds defining edges of the mounting flange's end panel and first and second side panels. An outside fold defines the second side panel of the mounting flange.

Abstract: A damper unit for an air circulation system. The damper unit includes a frame defining an air flow opening, a damper vane for opening and closing the air flow opening, and a drive mechanism for turning the damper vane between the open and closed positions. The vane of the damper unit includes a main body and vane turning surfaces that project outwardly from the main body. The vane turning surfaces are configured for converting air flow into torque for assisting the drive mechanism in turning the damper vane between the open and closed positions.

Abstract: A thermostat providing modulated or analog control of valves or dampers of an air management system. This permits operating a single cooling or heating stage with partially open valves or dampers as needed, since one full stage that is either fully on or off may not be easy to manage for effective air management of a particular type of building, zone or facility. The thermostat may also provide non-modulated control of multi-stage cooling and heating systems. The thermostat may even be used to control a modulated system having more than one stage of cooling or heating.

Abstract: A method for determining the presence of a leak in a water heater unit comprising a storage tank is presented. The present invention involves mounting one heating sensor on the lower half of the tank and another heating sensor on the upper half of the tank. Readings from both sensors are taken and compared to determine if the water heater tank has reached a steady state; if so, the cooling rate of the tank is determined. This cooling rate is compared to the historical natural cooling rate of the system, and based on the comparison a determination is made on the presence of a leak.

Abstract: A fail-safe apparatus for controlling fluid flow through a series arrangement of first and second solenoid-controlled valves is provided. The fail-safe apparatus includes fail-safe circuitry for controlling the operation of the first and second solenoid-controlled valves between unactuated and actuated states. Based on a given duty cycle, the fail-safe circuitry selects, actuates, deactuates, and/or maintains in the actuated or unactuated state one or both of the first and second solenoid-controlled valves. To facilitate such control, the fail-safe circuitry may include a switch operable to couple an input voltage across the first solenoid-controlled valve to cause a first current to flow therein. The fail-safe circuitry may also include an energy-transfer device coupled between the first and second solenoid-controlled valves.

Abstract: Terminal blocks adapted for placement on a printed circuit board using SMT techniques are disclosed herein. A terminal block in accordance with an illustrative embodiment of the present invention can include a main body, a terminal block header including a number of terminal inlet ports configured to receive wire or conduit, and one or more terminal leads adapted to make electrical contact with a number of attachment pads formed on the printed circuit board. An illustrative method of mounting the terminal block to a printed circuit board may include the steps inserting the upper portion of the main body through a terminal block opening, and then connecting the one or more terminal leads of the terminal block to attachment pads.

Abstract: A filtering system for use with a reservoir. The filter system includes a filter assembly capable of filtering particles sized 1.0 micrometers and larger and may, include a flow control device positioned to selectively provide fluid flow to the filter assembly. The flow control device may include an electrically actuated valve, such as a solenoid valve. The filter system may also include a fluid level detection mechanism operatively connected to the flow control valve.

Abstract: A device and method that may be used at nearly any place to set and adjust a control system such as a thermostat, controller or computer having numerous parameters and options that may be selected for desired operation of an air management system. One may remotely, via a personal digital assistant, configure, commission, select, set or adjust the parameters and options of a control system, which may include, but not be limited to, temperatures, humidity, sensors, volume of air movement, fan or air mover behavior, the percentage of added fresh air, modulated and non-modulated control of valves and dampers, stages of cooling and heating at various zones, control of heat pumps, heaters and air conditioners, modes of occupied, unoccupied or standby of respective spaces in a building, for day and night, at selected times, on certain days, for specific buildings at particular locations.

Abstract: Devices and methods for providing a switch for selecting which of a number of fuel valves receives power. The switch preferably provides a delay between the powering down of a first fuel valve and the powering up of a second fuel valve. Also included are systems and methods for providing an electrical, printed circuit board mountable safety switch for switching fuel sources in a multi-fuel burning system.

Abstract: Methods and systems are disclosed for meeting a fresh air ventilation threshold in a controlled space. In particular, and in some embodiments, a minimum ventilation threshold is met by using normal air handler fan cycles to minimize the energy cost of supplying the ventilation. Prediction methods may be employed to determine whether the air handler and damper need to be activated to meet a minimum ventilation threshold, even when the HVAC system is not currently calling for normal air handler fan cycles. In some cases, the past history of air handler fan run cycles is used to determine whether a fan should be operated now to provide additional fresh air ventilation. Alternatively, or in addition, predictions of future air handler cycles are used to determine whether a fan should be operated now to provide additional fresh air ventilation.

Abstract: Backlighting devices and methods for supporting and illuminating a display panel are disclosed. A display retainer and backlight device in accordance with an illustrative embodiment of the present invention may comprise one or more light pipes operatively coupled to a retainer housing that supports and illuminates an attached display panel. The retainer housing includes an optical waveguide that receives light collected by the one or more light pipes. A light scattering element and reflector may be employed to disperse and reflect the light rays to illuminate the backside of the display panel. A slot extending through a portion of the retainer housing may be configured to tightly receive an elastomeric zebra-strip, which electrically connects the circuit board to the display panel. A clip, tab or other fastening mechanism may be used to secure the retainer housing and display panel to the circuit board.

Abstract: Devices and methods for using multiple transformers to provide a power supply to a device or system. Included are systems for using multiple transformers and multiple fuses or circuit breakers to provide a power supply. In one embodiment two transformers and two fuses or circuit breakers are used to provide a power supply. Embodiments with greater numbers of fuses and transformers are also disclosed. Also illustrated are methods and devices using thermal circuit breakers to equalize current between multiple transformer sources or to compensate for differences between multiple transformers. Also included are switched schemes for assuring proper phasing of power supply transformers.