Abstract: A method of controlling a system with multiple air conditioner units having an outdoor machine and a plurality of indoor machines, which detects different driving modes input to each indoor machine, compares an outdoor temperature with first and second predetermined temperatures, and drives a corresponding indoor machine in accordance with the comparison results.

Abstract: A system for cooling outdoor golf practice tees is incorporated into a practice facility including a building that houses, perhaps, five or so practice tees, each of which is partially enclosed by building structure. Within the ceiling of the building, a single air conditioning unit is mounted having an outlet connected to an elongated manifold and within each enclosure, a vent is provided connected to the manifold and having a louvered outlet allowing adjustment of the direction of air flow from the outlet. A blower motor is located in the duct supplying air to the vent from the manifold and the blower motor includes a fan directed such that rotations of the motor result in blowing of conditioned air through the vent. Each enclosure includes a check control mechanism designed to receive money and responsive to receipt of the proper amount activating the blower motor for a prescribed period of time.

Abstract: The present invention relates to a dual zone solar sensor incorporating a calibratable diffuser overlying a vertically oriented circuit board having at least one photodetector affixed to either side of the circuit board in a vertical plane. Each detector preferably has a mutually exclusive hemispherical view. By mounting the photodetectors in the vertical plane, the dual zone solar sensor device is capable of providing information about the intensity of a source of incident solar radiation and the relative position of that source of radiation. While the angular responses of the photodetectors in their vertical orientation are very close to those desired by skilled artisans for a dual zone sensor, the addition of a diffuser that is slidable, and therefore calibratable, provides a method by which the angular response of each photodetector may be permanently calibrated to achieve a precise desired angular response.

Abstract: An automatic and improved electrical control for an automatic hydronic zone valve including a switching device for opening and closing solenoid valves based on adjustable temperature settings. Specifically, the preferred system involves a solenoid-controlled valve in which the solenoid is activated and deactivated by an electrical control circuit which relies on an external thermostatic switch and an internal relay to open and alternately close the following sub-circuits: a solenoid control sub-circuit which is directly connected to the valve solenoid, an AC to DC converter, relay control circuitry, a relay switch connection to a water circulator system and LED sub-circuits indicating power status and/or activation of the heating system. The solenoid control sub-circuit includes a series thermistor and a parallel capacitor to, respectively, slow the provision of electrical current to the solenoid to avoid "water hammer," and, quiet the electronic hum of the solenoid.

Abstract: A device for controlling the movement of a damper mounted in a housing between an open position and a closed position comprises a shaft rotatably secured to the damper for pivoting the damper between an open position and a closed position. A lever arm is mounted on the shaft for rotation therewith, and a spring is connected between the housing and the lever arm for normally urging the damper towards the open position. A motor is mounted on the housing and is actuable to overcome the force of the spring to move the damper to the closed position. A control arrangement associated with the housing is provided for regulating the speed of the damper as the damper moves from the closed position to the open position.

Abstract: In an air conditioning system for circulating a fluid which can change a phase between a gas phase and a liquid phase by a difference of a specific gravity between the gas phase and the liquid phase between an heat source side machine and a plurality of user side machines more than half of which are disposed below the heat source side machine, so that each of the user side machines performs a cooling operation, each of the user side machines is provided with a heat exchanger, a flow control valve for controlling a volume of said fluid supplied to the heat exchanger, a blow means for supplying an air-conditioned air to a room through the heat exchanger, a physical value detecting means for detecting a physical value relating to an air conditioning load such as a temperature and a signal controlling means for the operating and detecting portions, and wherein the heat source side machine is provided with a control means for communicating with said signal controlling means and outputting a control signal to said

Abstract: A system is disclosed for conveying network identifications of HVAC master controllers within an HVAC communication network to their respective zone controllers. Each master controller addresses and transmits its network identification to zone controllers within a predefined range of network addresses unless it encounters another master controller. The network identifications are used by the zone controllers to identify messages from their respective master controllers.

Abstract: A climate control system having a control means for receiving cool call signals and heat call signals from a plurality of thermostats. The control means blocking action by conflicting calls when the system is in a heat mode or cool mode. The system also preventing a single zone from dominating the mode of the control system and allow a conflicting call to be received after the control system has been in a particular mode for a maximum period or the conflicting call has been waiting for longer than a maximum period. The control system also properly adjusting the dampers to allow purging of ducts after heating and cooling mode and to allow zone or system ventilation upon request.

Abstract: An air-conditioning apparatus for allowing the temperatures of a first air-conditioning zone and a second air-conditioning zone to quickly approach the respective set temperatures by properly controlling the air flow rate and the ratio of fresh/recirculated air, even when the set temperatures differ from one another. The device includes a controller that determines whether the system is in a transitional period or in a steady state based on the deviation of the compartment temperature detected by the compartment temperature sensor from the first and second set temperatures for the first and second zones. If a determination is made that the system is in a transitional period, the controller acts to determine the flow rates of air being supplied to respective blowers as well as making the determination concerning the guidance ratio of the fresh to recirculated air.

Abstract: To enable performance of comfortable rear seat air temperature control when an air temperature control system is changed from a state where solely a front seat air temperature control unit is operating to a state where a rear seat air temperature control unit also is operating, when deviation between temperature Tr(Fr) detected by a front seat inner air temperature sensor and a temperature Tr(Rr) detected by a rear seat inner air temperature sensor is a predetermined temperature A or more, a temperature Tr'(Rr) used in calculating a rear seat target blowing temperature is taken to be Tr(Fr)--B'. Additionally, when the above-mentioned deviation is A or less, Tr'(Rr) is taken to be equal to Tr(Rr).

Abstract: A thermal zone demand controlled dual cascade arranged heat pump system and system controller for building spaces, having first and second heat pumps and having an air circulation system for circulating air to and from said thermal zones and including a conditioned air chamber having first and second heat exchange refrigerant coils being connected in refrigerant circulating relation respectively with the heat pumps. A plurality of thermal zone blowers conduct conditioned air, heated or cooled, from the conditioned air chamber to respective thermal zones of the building space. Electronic controller circuitry of the system is coupled for thermal demand control of the heat pumps and the thermal zone blowers for operation of the first heat pump to accommodate a predetermined range of thermal load and for operation of the second heat pump along with the first heat pump to accommodate a greater thermal load.

Abstract: This document describes an energy management system in which microprocessor based thermostats are used to control individual room temperatures in a multiple room building in accordance with the known occupancy status of the room. The occupancy status information, as well as other control parameters, are transmitted to the thermostats from a central computer program. The control of a heating and cooling appliances is performed by an algorithm running on the electronic thermostat, which performs this function in accordance with these downloaded parameters. The system, allows room occupants to control the temperature of an occupied room within preset limits, automatically limits energy usage in unoccupied rooms, and provides additional facilities for energy management and general building management.

Abstract: An air conditioner capable of separately controlling the temperatures of the conditioned air blown to first and second air conditioning zones and making respective blowing modes be common on both air passage sides, wherein the target blowing temperature is determined from the necessary blowing temperature corresponding to respective blowing modes and the opening degree of the air mix door is controlled based on said target blowing temperature, thereby the blowing temperature to the respective air conditioning zones in the respective modes being within a range of temperatures that cause no feeling of discomfort to an air conditioner user in the respective blowing modes.

Abstract: An integrated zoning circulator includes a priority controller, integral with the zoning circulator, for determining the priority given to the circulator in an individual zone of a multi-zone hydronic system. The zoning circulator also includes a priority circulator system for a multi-zone hydronic system having a zoning circulator at each zone, a plurality of control boxes each having a thermostat, one control box being associated with each circulator, and, a plurality of priority controllers, one priority controller being associated with each control box. Each priority controller, when activated, functions to assure that when the associated thermostat calls for the circulator to operate, other circulators in non-priority mode are prevented from operating simultaneously.

Abstract: A circuit for regulating the air conditioning of premises that are stationary or mobile, the premises being air conditioned by means of a conditioning unit controlled by a corrector that receives on its inputs both a reference temperature magnitude and a magnitude representative of the temperature of the premises, the circuit including a member for non-linear and non-stationary simulation of the assembly constituted by the conditioning unit and by the premises, and wherein the corrector comprises means for handling saturation in such a manner as to take account of amplitude limitation in the signal for controlling the process and the model of the process. The invention is particularly applicable to regulating the air conditioning of rail vehicles.

Abstract: The difference between the zone temperature and the scheduled setpoint, or .DELTA.t, is the basic data from each zone. Communication between the air handler control and the air terminal control is provided via the air system control so that the system is temperature, rather than pressure, responsive.

Abstract: A process is disclosed for adjusting the valve position of flow control valves which govern the flow of a heat exchange fluid to a plurality of individually controlled zones. The process resides primarily in a system controller in communication with a number of separate zone controllers. The system controller periodically obtains temperature and mode of operation information from each zone controller and thereafter computes the amount of time necessary to change the temperature by one degree in each zone. The computed amount of time per degree change in temperature is compared with the average for all zones in a similar mode of operation. Offsets are calculated for active flow control valves in each zone depending on whether the computed amount of time per degree change in temperature is above or below the average for all corresponding zones in the same mode of operation.

Abstract: A temperature control system for a building structure such as a household is divided into a plurality of zones. A controller acts between temperature sensing devices in each of the zones and an adjustable thermostat which allows the desired temperature in the building structure to be selected. The controller allows individual zones to be selected to receive conditioned air and allows one of the selected zones to be designated as a control zone. A heating or cooling decision for the temperature control system for all of the selected zones is made based on the difference between the thermostat setting and the output of the temperature sensing device in the control zone. The control zone can be changed manually to the next available selected zone. Different visual indications are given for the control zone and the selected zones. Zones with faulty temperature sensing devices cannot be control zones or selected zones.

Abstract: Apparatus for heating or cooling the levels of a multi-story building. A single furnace-air conditioning unit is utilized to heat or cool the levels as dictated by the settings of thermostats in each level. An arrangement is employed to direct heated air from the upper level to the lower level during the heating cycle to lessen temperature differentials between the upper and lower levels.

Abstract: Device for selective climate control in vehicle cabins having a first air-vent duct (18) and a second air-vent duct (22) on respective sides or different zones in a vehicle cabin. The duct temperature on each side is measured and the duct adjustment is regulated by inner feedback control circuits. The cabin temperature (Tc1, Tc2 resp.) on both sides is measured, preferably at approximately head level, and fed to outer control circuits which determine the desired duct temperature as the deviation between the desired cabin temperatures (Tcs1, Tcs2 resp.) set by means of separate control knobs (38, 44) and the measured cabin temperatures (Tc1, Tc2 resp.). Desired duct temperature signals (Dts1, Dts2 resp.) are connected as input signals to respective inner control circuits.

Abstract: Primarily-conditioned air is discharged from a heat source, and distributed into a plurality of rooms through a duct. The duct has a plurality of air passages connected to the rooms, and a damper is provided in each air passage for adjusting the flow of the primarily-conditioned air. Further, a heat exchanger is provided in each air passage, and connected to a refrigerating cycle for the heat source. The thermal load in each room is detected, and the required air flow in the room is determined based on the thermal load. The opening degree of a damper corresponding to the room is controlled on the basis of the required air flow. Each damper has an allowable minimum opening degree. When the opening degree of any damper becomes equal to the allowable minimum value, refrigerant flows into a heat exchanger corresponding to the damper, thereby correcting the temperature of the primarily-conditioned air.

Abstract: An improved micro-computer operated control device for an air conditioning system which is specially characterized in that the air volume produced by the air conditioning system can be automatically varied in correspondence to the temperature of a closed space is disclosed. A number of temperature sensing components are constantly monitored by a processing unit of the temperature data thereof which are compared with predefined temperatures provided by a function setting unit; the results of the comparisons are transformed into corresponding signals which are then transmitted to an output control unit; and a voltage regulator is actuated in accordance to the signals to adjust the voltage of the motor of a fan supplied by a power source so that the operation speed of the fan can be constantly varied in correspondence to the external temperatures, resulting in the air volume delivered by the fan varied accordingly.

Abstract: A system and method for controlling the operation of a Heating, Ventilation and Air Conditioning (HVAC) system for use primarily in a building having more than two controllable temperature zones. Rooms having a priority for heating or cooling are identified as such in a controller. The controller sums Temperature Differences from all controlled spaces and causes the HVAC system to operate in a first mode (e.g. heating) if the sum has a first relationship to a preselected value (e.g. sum>=0) and causes the HVAC system to operate in a second mode (e.g. cooling) otherwise.

Abstract: An unit-type air conditioning system is provided to enable low-load operation of an absorption chiller heater, to thereby improve the load responsiveness, and to use such a chiller heater as an outdoor unit. A plurality of burners are provided in a high temperature generator of the absorption chiller heater, thereby enabling the low-load operation. A refrigerant return valve is provided so as to speed up the stop operation. Flow rates of pumps are controlled in accordance with detected values of temperatures in the chiller heater and a load change, thus improving the load responsiveness. Further, in the air conditioning system with this chiller heater serving as an outdoor unit, required operation prediction is performed on the basis of outer signals from load units and the like, and prediction control according to its result is conducted, further improving the load responsiveness.

Abstract: A bypass damper for a forced air system comprising a freely pivotable damper blade with bent portions at the ends thereof and having an adjustment mechanism for adjusting the pressure set point of the damper.

Abstract: An interior thermal conditioning method and apparatus with improved zone control is disclosed. The thermal conditioning apparatus, such as a heat pump assembly, generates a desired thermal condition which is conveyed by a thermal distribution medium to a number of zones within a multiple zone building. Each zone includes a heat exchange device for receiving the thermal distribution medium. Each zone also includes a thermostat which is used to set a desired temperature range and to indicate the prevailing temperature. When the prevailing temperature is inconsistent with the desired temperature range, a conditioning request is generated. Rather than immediately responding to the conditioning request, the heat pump controller assesses the temperature of the thermal distribution medium to determine whether it is within a target range.

Abstract: A temperature control system for a residential zoned forced air system which maintains programmed temperature setpoints for specific periods in each zone having hold, override, and vacation modes which can temporarily alter the programmed temperature setpoints and time periods for either individual zones or all zones until the next programmed time or the temporary modes are released.

Abstract: A fan-powered mixing box assembly through which conditioned air is supplied to a plurality of zones is controlled by a programmable fan-box monitor. The assembly comprises a mixing box, a multi-speed fan and a heating element having several stages. The monitor receives data from and transmits data to a plurality of programmable zone thermostats each of which controls a zone via a duct damper through which air enters the zone. The monitor receives data from duct temperature and duct air pressure sensors for use in controlling the fan and heating element. Also, the monitor is responsive to signals representative of the real time for operating the assembly in setback modes when the various zones are not occupied. The monitor modulates a master damper for control of supply air.

Abstract: An air conditioner for a building having a plurality of rooms has heating and cooling modes. A duct system connects the air conditioner to the individual rooms. A plurality of control valves are coupled to the duct mens for individually controlling the flow of air to each room. A first circuit is provided for generating a heating or cooling request signal from each room. A second circuit is provided for summing the number of the heating and cooling requests and providing summation signals of each. A third circuit is provided for sensing the greater of the two summation signals and activating the air conditioners to the mode corresponding to the greater of the summation signals. A fourth circuit is provided for activating the control valves controlling flow to the rooms which do not provide a part of the greater summation signal to the closed position.

Abstract: An air conditioning for a room of a high-rise building, for example, is carried out in consideration of the difference in temperatures in a central interior zone and a circumferential perimeter zone of the room changeably to heating and cooling in accordance with an operation mode and a room temperature set point. In the actual air conditioning, a room temperature in the interior zone is first set and an actual room temperature in the perimeter zone is detected. The set room temperature in the interior zone is compared with the detected room temperature in the perimeter zone to thereby select an operation mode (heating or cooling) of air conditioning of the perimeter zone by an operation mode selecting unit.

Abstract: A system for controlling the operation of an HVAC system which includes a direct expansion coil, a condenser, a pre-cool coil, and a control system. The control system includes a controller and sensors. The controller receives signals indicative of air flow through the direct expansion coil from the sensors, compares the received signal to a stored air flow rate, and disables the compressor if the stored air flow rate is equal to or greater than the stored value. The controller is also adapted to vary air flow into an occupied space for small changes in the cooling load. In addition, the controller can artificially load the compressor during periods of small cooling load by restricting flow of a cooling agent between the cooling tower and the condenser, or by directing warm water from the condenser through the pre-coil coil.

Abstract: A duct type of air conditioner wherein temperature in a plurality rooms are controlled independently, and which after having controlled opening and closing of dampers for the rooms, is capable of controlling air volume, controlling the opening and closing of each damper depending on the temperature in the room with the corresponding damper, or determining atuomatically whether to select heating and cooling, depending on each room temperature and an external air, thereby realizing an optimum and effective operation control. When the total opening degree of the dampers becomes less than a predetermined amount the opening degree of the damper feeding air to the room with the greatest heat load is revised to be open.

Abstract: An air conditioner having an indoor unit placed in a room to be heated or cooled, and a draft directing apparatus, such as a vertically tilting louver, which can assume a first position directing an outlet draft toward the location where a user is normally positioned, e.g., downward, and a wecond position directing the output draft away from said location, e.g., upward. The draft directing apparatus is controlled to assume the first position and the second position alternately, in such a manner that the proportion of the time for which the draft directing apparatus is in the first position is adjusted in accordance with the detected temperature of the draft. This adjusts the proportion of the time the draft is directed toward the user, and it is therefore possible to adjust the stimulation affecting the user.

Abstract: A refrigeration system for temperature conditioning several comfort zones includes several VAV (variable air volume) valves each having a hot water coil conveying water whose flow rate is regulated by a PWM (pulse-width modulated) solenoid valve. Each VAV valve is connected to a supply air duct conveying cool supply air. When a zone's temperature is above a set point temperature, the opening of the VAV valve is modulated to meet the cooling demand, and the water coil is shut off. When a zone's temperature is below the set point, the VAV valve is opened to provide a predetermined constant airflow rate and the hot water coil's solenoid valve is cycled open and closed in a pulse-width modulated manner to meet the heating demand.

Abstract: A valve is provided with one inlet and two outlets with one of the outlets being normally closed by a valve in the form of a film disc carried by a flexible blade. A magnetic pad secured to the blade is attracted by the proximity of an actuator carrier magnetic element to cause the flexing of the blade to open the normally closed outlet and to close the normally open outlet. The actuator may be either thermally or electrically actuated and is suitable to override a bleed thermostat to permit warm-up of an overcooled area or to cause a switchover in operation between a heating and cooling mode by connecting the appropriate bleed thermostat so as to control the inflation of the bellows.

Abstract: An HVAC system for a plurality of zones comprising an air handling unit including a blower, a plurality of heating stages and a plurality of cooling stages. The air handling unit is connected via ducts to each of the zones, each zone having an air outlet provided with a two-position damper which is either open or closed and a thermostat for providing an input signal to a microprocessor. The microprocessor has outputs for activating motors to move the dampers and outputs for activating the heating and cooling stages. The system includes an automatic mode of operation in which the microprocessor controls the number of stages of heating or cooling which are energized in dependence on the difference between the number of zone therostats calling for heating and the number of zone thermostats calling for cooling.

Abstract: A microcomputer-controlled thermostat for use in monitoring and controlling a single zone HVAC system which provides conditioned air to one or more zones. The thermostat can be programmed and used either as a monitor thermostat to control the HVAC unit alone and/or to control the HVAC unit and its damper in a multiple zone mode. The thermostat is also programmed as a slave thermostat in a master-slave relationship with a monitor thermostat. The microcomputer memory is supplemented with additional ROM containing control algorithms for use in system operation.

Abstract: An information transmission system using a pair of transmission interconnections to supply power from a collection station to an operating station, and to transmit information back based on the collection station providing a changing voltage on the two interconnections and the operating station modulating the amount of current drawn about a reference current to represent information.

Abstract: A dual air conditioner having a pair of air conditioning units for front and rear seats within the compartment of a vehicle adjusts the temperatures of air output to the front and rear seats in accordance with the difference between the temperature desired at one of the front and rear seats and a typical temperature sensed within the compartment corrected by a function of the difference between desired temperatures in order to condition the front and rear seats to the respective desired temperatures.

Abstract: An air conditioning system for buildings includes a plurality of air conditioners on the different floors, a cooling gravity type heat pipe connecting vaporizers in the air conditioners with a cold thermal source installed at the top of the building and a warming gravity type heat pipe connecting a condenser of the air conditioners with a hot thermal source installed in the basement of the building. The heat pipes are, respectively, provided with flow control valves at the inlet of each vaporizer and the outlet of each condenser. Each air conditioner is provided with a thermistor for detecting the temperature of the returning air and a liquid level detection switch for detecting the liquid level of the thermal medium in the vaporizer. The flow control valves are respectively controlled based on the detection signals issued by the thermistor and the liquid level detection switch.

Abstract: A microcomputer-controlled thermostat for use in monitoring and controlling a single zone HVAC system which provides conditioned air to one or more zones. The thermostat can be programmed and used either as a monitor thermostat to control the HVAC unit alone and/or to control the HVAC unit and its damper in a multiple zone mode. The thermostat is also programmed as a slave thermostat in a master-slave relationship with a monitor thermostat. The microcomputer memory is supplemented with additional ROM containing control algorithms for use in system operation. Logic circuitry is used to recognize commands as being for operation of the HVAC unit, the operation of the damper, or selection of which systems sensors are to be enabled. A real time clock circuit in the monitor thermostat is used to supply data for time-based system operation.

Abstract: A pressure independent variable air volume valve (VAV valve) functions as a pressure dependent valve upon detecting a malfunctioning airflow indicator. Under normal operating conditions, the VAV valve modulates supply airflow to a comfort zone in response to the zone temperature and the rate of airflow through the valve. If the airflow indicator fails, the VAV valve modulates the supply airflow in response to the zone temperature, independent of the airflow indicator.

Abstract: A temperature control system for an air conditioning system that services plural zones provides priority of one or more selected zones of the conditioned air flow relative to the other unselected zones. Priority is achieved by closing those dampers associated with the unselected zones to direct the conditioned air flow into the selected zones. The temperature control system also provides for fail-safe operation by utilizing dampers biased in the open position and by preventing all dampers from being closed at the same time when conditioned air is flowing.

Abstract: A microcomputer-controlled bypass controller for use in maintaining a minimum airflow through a heating/cooling unit and limit the static pressure in the supply air truck duct. The bypass controller functions to control the operation of a bypass damper which regulates the airflow through a duct that bypasses air from the supply truck duct to the return. The bypass controller also measures the air flow via an air flow sensor and communicates with a microcomputer-controlled thermostat to coordinate transitions between heating and cooling cycles in association with a second sensor which monitors the duct temperature.

Abstract: The advanced zone damper incorporates an adjustable, spring loaded damper door control which allows any percentage up to 50% of the total air flow to pass through a locked damper door when only two dampers are used in a multizone heating and cooling system. The stated percentage is relative to when two dampers are used, and may vary greatly with system design and the number of dampers and zones in the system. A humidistat and manual control over system functions is also a great improvement over the thermostat control only. Often in a two or more zone system, where the air conditioner is large enough for the building, there may be humidity control problems in any zone which the present invention's controls compensate for by damper doors being unlocked simultaneously while the air conditioner and the heater may both be operating simultaneously so that humidity is removed by the air conditioner while cooling, and heat is added by the heater. This process removes humidity but may not change the air temperature.

Abstract: A system for controlling the operation of a plurality of dampers serving ventilation apertures in the structure of a building, which system comprises a plurality of actuators, one or more to be associated with each damper and to actuate the damper between an open and a closed position; the actuators incorporating means for receiving a signal from a controller, for identifying that that signal contains instructions relevant to the damper which that actuator actuates; the plurality of actuators being adapted to be connected in series with the controller via a single connecting cable.

Abstract: An air duct type multizone air conditioning system having air dampers and corresponding thermostats in respective zones under the control of a main controller. The main controller can override desired temperatures selected by the corresponding thermostats in any of the zones and automatically detects the number of the number of zones, the presence of an auxiliary heater, and a heat pump, and the presence of an air damper and corresponding thermostat properly located in the same zone. The main controller also receives information regarding the operating cost of the heat pump and the auxiliary heater to ensure their cost-effective use.

Abstract: The temperature of a serviced area or zone is cost efficiently maintained within a prescribed range by establishing a prescribed fan cycle period, during which period the fan is both operative and non-operative at variable intervals. The temperature of the serviced area is monitored and averaged for each given cycle. The fan run time is then determined by a CPU for the succeeding cycle dependent upon the difference between the average measured temperature and a prescribed balance temperature.

Abstract: Method and apparatus for maintaining excess air control in a gas furnace. A pressure switch is placed across a heat exchanger to indicate when, while accelerating the inducer motor speed during purging operation, the pressure drop reaches a predetermined level. When that occurs, the motor speed is sensed and recorded. When the furnace is subsequently fired, the desired inducer motor speed is obtained by modifying the recorded motor speed on a correction factor derived from empirical data obtained from a gas furnace operating under selective variable conditions.

Abstract: A building air conditioning and heating system includes an air handling system set up to separately control different zones of a building. The air handling system has a blower connected to an air duct system in the building. At least two thermostats are positioned in different portions of the building for separately controlling the heating or the air conditioning in that portion of the building. A plurality of dampers are positioned in the air duct system, with each damper adapted to be opened and closed by gravity or air pressure. A damper locking means locks each damper in a closed position responsive to actuation by an electrical switch so that one zone of the building can be air conditioned or heated as desired. The thermostat can acutate the dampers and can control the temperature in one zone portion of the building while the other thermostat is disabled. Each damper has an electrical solenoid for locking the damper in one position.