Abstract: An improved automatic energy-efficient temperature control system for a room or suite of rooms. This system is used in addition to the normal temperature responsive switch which is used to control a heating and/or cooling unit. This system involves a second temperature sensitive switch, set to a temperature which utilizes less heating or cooling. While using the normal operating temperature while persons are in the room, the second temperature responsive switch is short-circuited by a manual switch, or one operated by a magnetic or gravity means. The control of the shorting switch is made responsive to the entry or departure of persons from the room. Thus while they are present, a more comfortable operating temperature is provided and when they are absent from the room, a more energy-efficient situation is imposed.

Abstract: A method for controlling a temperature of an object to be cooled or heated by a cooling/heating apparatus is improved in that when all of a plurality of temperature detectors for detecting a temperature of the object are operating normally, the cooling/heating capacity of the cooling/heating apparatus is regulated in response to input signals consisting of the detection temperature of the respective temperature detectors according to an operation pattern set in a normal time thermostat. When it has been determined that a certain temperature indicated by a detector is abnormal, then the cooling/heating capacity of the cooling/heating apparatus is regulated in response to input signals consisting of the detection temperatures of the other normal temperature detectors according to an operation pattern set in an abnormal time thermostat that is different from the operation pattern set in the normal time thermostat; thus the temperature of the object can thereby be controlled.

Abstract: An adaptive optimum start/stop controller for controlling an air treatment apparatus at a reduced energy consuming level during periods of non-occupancy of a building and for energizing the air treatment apparatus before occupancy so that the building is comfortable by occupancy, the controller including a temperature sensor for sensing space temperature within the building, a controller responsive to the temperature sensor and to real time for determining optimum start/stop times so that the building is controlled at energy conservation levels during non-occupancy and comfortable levels during occupancy, the controller adjusting the optimum start/stop times based upon the accuracy of prior start/stop times, and a communication channel for connecting the controller to the air treatment apparatus.

Abstract: In this system, a receiver having adjustable sensitivity to movement by a room occupant picks up continuously generated compressional waves of ultrasonic frequency reflected from the occupant. Movements of the occupant cause changes in frequency of the reflected wave which are detected, and pulses are applied to a timer which applies a timed voltage to a logic circuit. A signal indicating a difference between a preset ambient temperature and that sensed by an electronic sensor is applied to the logic circuit. The logic circuit is arranged to actuate relays to turn a selected heating or cooling unit on if occupant movement is detected and ambient temperature difference exists, and to turn the selected unit off if the room becomes unoccupied. The logic circuit is effective to turn on the heating unit if ambient temperature falls below a preset, low other temperature, even if the room is unoccupied.

Abstract: An air conditioner including a room temperature detector, a room temperature adjuster and a controller is disclosed which is provided with a photodetector, and in which the temperature set in the room temperature adjuster is changed on the basis of the illuminance detected by the photodetector, and a signal for controlling a compressor is generated by the controller in accordance with the temperature thus changed.

Abstract: A room temperature control system includes a transmitter-receiver unit for producing an acoustic standing wave pattern in a room and for producing a signal when that pattern is disturbed by motion in the room. A logic circuit provides timing signals and interprets a pattern disturbance signal to determine whether it evidences room occupancy. The timing and interpreting sequence is initiated by a switch which detects opening and closing of the room door. Temperature control by the room thermostat is permitted when the room is occupied and control within a wider range can be provided when it is not occupied.

Abstract: A control system for selectively regulating the operation of water heating tank in accordance with anticipated hot water demand thus eliminating storage heat losses during periods when hot water is not required includes a remote control unit, a relay unit and first and second thermostats, all electrically connected selected circuits with an electric heating element located within the tank. The first and second thermostats are arranged to sense the temperature of the tank water and the operating temperature (115.degree. F.) of the first thermostat is lower than that of the second thermostat (150.degree. F.). The remote control unit includes a three-position switch in circuit with the relay unit and first and second thermostats to permit continuous energization of the heating element under control of either the first thermostat in the first switch position or the second thermostat in the second position to provide a continuous supply of hot water at either 115.degree. F. or 150.degree. F.

Abstract: An air conditioner control system comprises an air conditioner which includes a heating unit, a cooling unit and an internal thermostat, a switch unit for activating the air conditioner and a sensor unit for controlling operation of the switch unit. The sensor unit includes a sound level detecting circuit and an air temperature level detecting circuit and is positioned so as to sense the sound level and temperature level in the room in which the air conditioner is installed.In operation, if the sound level rises above a threshold associated with occupancy of the room, the air conditioner is activated and the heating and cooling units are controlled by the internal thermostat. When the sound level falls below the threshold, after a preset period the air conditioner is activated only when the room temperature departs from a temperature range which is preset in the unit.

Abstract: A two-stage thermostat means for an add-on heat pump installation provides separated control of a furnace and a heat pump. The two-stage thermostat means utilizes a single pole, single throw switch means, and a single pole, double throw switch means to properly stage and control a heat pump and a fossil fueled furnace so that they do not overlap. The control of the temperature of the heated area is independent of any need to connect a circuit between the thermostat in the heated area and any type of thermostat at the heat pump itself.

Abstract: Methods and circuits for providing auxiliary or remote temperature set or set-back capability in comparator-based thermostatic temperature control systems. In particular, the invention is applicable to thermostatic control systems of the general type including a temperature-responsive source for producing a temperature-dependent voltage as a function of sensed temperature, a reference voltage source for establishing a temperature set point, a voltage comparator having a comparison input and a reference input for producing a control output signal for energizing a thermal conditioning element when voltages applied respectively to the comparison and reference inputs have at least a predetermined relationship with respect to each other, an electrical connection between said temperature-responsive voltage source and the comparison input, and an electrical connection between the reference voltage source and the reference input.

Abstract: A control circuit is disclosed for controlling an air conditioning and/or heating system in a region comprising a first circuit for establishing electrical signals corresponding to an upper and lower temperature of a first temperature range. A second circuit is provided for establishing electrical signals corresponding to an upper and lower temperature of a second temperature range. A presence sensor is provided for detecting the presence of a person inhabitating the region. A logic circuit is connected to the aforementioned circuit for controlling the system in accordance with a first temperature range when a person is inhabiting the region and for controlling the system in accordance with the second temperature range when the region is void of inhabitation by a person.

Abstract: A system for the control of a load such as a heating or cooling plant in response to changes in an external parameter, specifically ambient temperature, comprises a loop circuit with two conductors connected at an input end across a power supply and at an output end across a switching network, the load being inserted in one of these conductors. A high-impedance voltage multiplier connected across these conductors downstream of the load, in parallel with the switching network, supplies the necessary operating voltage to a parameter sensor such as a thermostat even when that network is in a low-impedance state so as to draw a maximum load current. The switching network may include a voltage clamp provided with a source of reference potential, e.g. a primary battery, which upon failure of the normal power supply can act as a standby supply insuring continued operation of a timer serving for a periodic switchover between different temperature thresholds for the thermostat.

Abstract: A water heater control system designed to conserve energy, in part by anticipating hot water demand as a function of usage, utilizes refined design features to effectively automatically switch the water heater's thermostat between a high and a low setting in response to actual use of hot water and the heat of the water at the moment. The basic purposes of the invention are first, the prevention of the system from switching into the "high" mode when in fact adequate hot water is still present in the tank, and second, the reduction of the length of the burner firing time at times when a long burn is not necessary. These features include a specialized heat sensor switch which permits the trigger temperature of the switch to follow the seasonal temperature of the incoming water, also a stack gas switch for further refining the system's function. Remote control and a special mounting means are also included in the refined control system.

Abstract: A heating system for an inhabitable enclosure having a first heating system that maintains a first temperature in the absence of persons in the enclosure and a second heating system that maintains a second elevated temperature using outside fresh air with control means to detect the presence of a person in the enclosure to energize the second system.

Abstract: A thermostat device for motels/hotels requiring the guest use a key to select a desired room temperature which in turn requires that the thermostat must be set back to a preset temperature when guest desires to lock the door to his motel/hotel room upon leaving the room.

Abstract: An energy saving thermostat having a selected offset temperature time period previously programmed with means to shift the time period ahead or backward.

Abstract: A power saving unit which also assures room security by requiring a door to be properly locked before particular electric loads will be energized. The system includes switches connected to the door providing indication of whether the door is open, closed, or locked. A control circuit controls the energization of a particular electric load connected to the system. A suitable gate responds to the door being locked or opened to activate the control circuit for maintaining the load energized. It responds to the door being closed but unlocked to keep the load energized for a predetermined interval of time after which the load will be switched off. Suitable indicator lights are provided to remind the guest to lock his door in order to retain the loads energized.

Abstract: A thermostat has a temperature responsive element coupled to a pivoted arm which closes the circuits to operate temperature control apparatuses. A slotted cam with leaf spring members projecting from one end is slidably mounted to move toward or away from the pivoted arm in response to removing or replacing a weight which operates a cam follower element connected to the slotted cam. When the slotted cam is positioned away from the pivoted arm, the thermostat operates in conventional fashion. When the slotted cam is positioned toward the pivoted arm, the arm has the additional load of the leaf spring members to overcome, and the set point temperature of the thermostat is changed.

Abstract: A system for alternately activating and deactivating a load comprises a high-resistance d-c circuit branch connected across a power supply downstream of a load-operating impedance, this branch including a voltage limiter and a voltage multiplier in series with each other and with a switching stage responsive to commands from a timer and/or a parameter sensor such as a thermostat. The junction of the voltage limiter and the voltage multiplier is connected to one input of a differential amplifier whose other input is energized with either of two potentials, respectively higher and lower than that of the junction, by the switching stage.

Abstract: Three or more temperature sensors are positioned at various selected locations in a building. These sensors are connected to an averaging circuit whose function is to provide an electrical signal which is functionally related to the average temperature of all these sensors. This electrical signal is compared with another signal which is related to a pre-determined reference temperature for the building. If the electrical signal related to the reference temperature is greater than the electrical signal related to the average temperature indicated by the sensors, a comparator circuit turns a boiler on to heat the building. When the reverse situation is true, the comparator circuit operates to turn the boiler off.

Abstract: A temperature controlling system (10) is normally controlled by a thermostat that is superseded by a remotely controlled thermostat (21) in response to a remote control signal transmitted over telephone lines that retains control for eight hours established by an eight-hour clock (14). A response oscillator with warning thermostat (13) provides an answering signal indicating that the superseding thermostat is exercising control over the temperature controlling system of pitch which is varied to indicate control and distinctly lower when the warning thermostat indicates the temperature is less than a predetermined value.

Abstract: A temperature control system for a building has a temperature responsive means or thermostat in the space for controlling a temperature conditioning apparatus furnishing temperature condition medium to the space. A time control apparatus provides for a reduction or deviation of the space temperature during certain time periods for the purpose of energy conservation and/or comfort. The space temperature is restored to the normal temperature by a pickup operation. The magnitude of temperature setback initially selected or to be maintained during the setback time period is automatically adjusted by responding to the actual building heat load, so as to keep the time and heating capacity needed to restore the space to the normal temperature within certain limits.

Abstract: Method and apparatus for controlling the temperature in greenhouses, the nominal value of the temperature being adjusted between a higher daytime temperature and a lower night temperature. In order that the plants in the greenhouse shall not be exposed to a shocklike reduction of the total energy supply to the plants if a considerable sunlight energy quantity has been supplied to the plants in the daytime, the nominal value of the night temperature is controlled in dependence of the sunlight energy quantity received by the plants, in such a manner that the night temperature is adjusted to a higher value at a higher sunlight energy quantity.

Abstract: The present invention discloses an energy conserving thermostat for controlling the supply of energy within a commercial or industrial building during unoccupied periods and for providing additional energy to the building when required. The present system includes: a night thermostat for establishing a low temperature necessary for the maintenance of the building during a non-occupancy period; a seven-day timer clock calibrated for every hour of each day, with manually adjustable pins on the clock settable for a time interval within each day during which a normal comfort condition is required; mechanical switch means responsive to such pins of the clock; electrical switch means including a relay energized by operation of the mechanical switch; and an override timer including a time meter and a manually operable switch to increase the time setting for any day wherein an unusual supply of energy is required within a zone of the building. The extra time of such setting is recorded on a time clock meter.

Abstract: A control arrangement is provided for a heating system having heat outlets each controlled by a solenoid valve (210). Each heat outlet is connected to a pair of thermostatic switches (411, 413) operative at different temperatures. A time switch included in a central control means (108) is operative to selectively energize a pair of bus-bars (530, 532) at different times, thereby to provide common output signals for actuating the heat outlets via different thermostatic switches (411, 413) at different times to provide different heat outputs during different parts of a predetermined period of time (e.g. 24 hours). The central control means (108) includes a plurality of manual switches (540) each connecting the time switch output bus-bars (530, 532) to the thermostatic switches (411, 413) of an associated one of the heat outlets to manually set the heat output of the heat outlet.

Abstract: An energy conservation arrangement for a hotel guest room or other room lockable by a key (26) comprises a key reception module (10) disposed inside the room to receive a tag (24) of the key when the guest enters the room. Control means (12) is responsive to the tag (24) being received by the key reception module (10) to enable the use of room light(s) (16) and electrical power outlet(s) (18) and to allow a room air conditioner (20) to function normally. When the guest removes the tag (24) from the key reception module (10) prior to leaving the room, the control means (12) disables use of the light(s) (16) and power outlet(s) (18) and puts the air conditioner (20) into a minimum power consumption mode.

Abstract: The room temperature controller of the present invention is adapted for use in a room in which the temperature is controlled by a thermostat coupled to an air conditioner unit. The room temperature controller includes a detector positioned within the room for detecting from a distance the presence of an occupant within the room. A logic and control circuit is coupled to the output of the detector and to the thermostat. The logic and control circuit modifies the normal operation of the thermostat when an occupant is not detected within the room to reduce unnecessary heating and cooling expenses. This circuit also enables the thermostat to operate normally for timed intervals when an occupant is detected within the room.

Abstract: A remote control device for controlling the operation of a conventional domestic water heater (18) used singularly or in conjunction with a solar heating system. The control device comprises a remote control head (10), which has an indicator (12) for conveying the status of the water heater (18) and the temperature of the water contained therein and a multi-positional manual switch (14) for selecting the mode of operation of the water heater (18) and a remote controlled heater switch (16), electrically connected to the remote control head (10), which controls power to the water heater (18) in response to signals from the remote control head (10). Therefore, the operation of the water heater can be controlled according to the needs of the user.

Abstract: The problem of adequate flexibility and reliability in apparatus for controlling temperatures in a plurality of zones is solved by a clock and digital logic circuits, together with a temperature sensing circuit portion effective in combination with platinum film-type temperature sensors, which produce effective sensing over a wide range of temperatures. The control apparatus automatically effects two temperature sets per twenty-four hour period for each zone with an optional temperature set for weekends for all zones and has a display of current time and a display of temperature for each zone.

Abstract: An energy conserver for use with a heating and air conditioning unit comprising a three position lock switch selectively moveable between a first, second and third position and a thermostatic control unit including a cooling control switch and a heating control switch each selectively moveable between a first and second position such that the heating and air conditioning unit operates continuously in the cooling mode and heating mode when the three position lock switch is in the first and third position respectively and selectively operates in the cooling or heating mode when within either of two preselected temperature ranges.

Abstract: Method and apparatus for generating a digital data word representative of the position of a switch element which is selectively engageable with one of a plurality of driver conductors which are utilized for conducting actuating signals from a source to a data display system of the type having a plurality of display elements for visually indicating alphanumeric data. The display elements have visually perceptible and imperceptible data indicating states and are characterized by a lagging response to either the application or interruption of the actuating signal wherein a turn-on or turn-off transition interval elapses during a change from one state to the other with the preexisting state of the display element appearing to an observer to remain unchanged during the transition interval. The actuating signals are periodically applied during a load energizing interval through one or more of the driver conductors and are interrupted during a sampling interval.

Abstract: A control apparatus for regulating a building perimeter temperature change system, which may be a heating system, a cooling system, or both. The control apparatus operates in conjunction with a central heating system which operates to adjust temperatures in the building. The building is characterized by net heat gains or losses at the building perimeter. These net heat gains and losses are made up by the building perimeter temperature change system under the regulation of the present control apparatus. The apparatus includes a heat flow sensor for mounting upon an exterior building element to generate a sensor signal proportional to the direction and magnitude of heat flow to or from the building element. A controller responsive to the sensor signal operates the temperature change system so that the rate of perimeter heating or cooling is directly proportional to the measured rate of heat loss or gain through the building element.

Abstract: An energy conserving thermostatic control system having digitally implemented control functions for use with a heating and/or air conditioning system is disclosed. The digital thermostat includes an LCD data display for simultaneously displaying present time and ambient temperature. Slide switches are provided for setting and indicating set point information such as day temperature, night temperature, night-to-day transition time, and day-to-night transition time. The switch contacts of each slide switch are multiplexed to the display driver conductors for conveying time and temperature set point data during time and temperature scan intervals which alternate with a display interval. Strobe signals which are applied to the driver conductors are counted during the alternate scan intervals for selecting a day temperature different from a night temperature, for selecting the times whichdivide night from day and for providing set-back to night temperature during a predetermined time of the day.

Abstract: An improved thermostat having two modes of operation selected by a pressure signal from a central source, which includes a separate set point for each mode of operation. Each set point has a scale which is clearly visible without removal of any parts of the thermostat. Each set point is also adjustable either by an adjuster that can be operated by occupants or only by authorized personnel having a tool fitting the opening in the set point adjustor. Adjustors can be provided with restrictors which limit set point adjustment to a predetermined range of temperatures and which can be adjustable by authorized personnel, or can be factory set.

Abstract: A control system for energizing and de-energizing external loads in series with a source of electricity incorporates a rectifying network having inputs in series with the alternating current source and each external load. The control system incorporates one electronic switch, such as a triac, and one part of a rectifying network to energize and de-energize each external load. The triggering of a particular electronic switch is made in response to a desired combination of externally sensed parameters obtaining predetermined magnitudes. The same or different sensed parameters may also be used to activate any other external load when these sensed parameters obtain a second set of predetermined magnitudes, which may be identical with the first set of predetermined magnitudes.

Abstract: A switching system for controlling operation of conventional environmental apparatus of the type having an electrical connection adapted to be coupled with a supply of electrical current includes a switching circuit in a first housing for making and breaking a circuit connection between the connection and the current supplied, and a control circuit electrically coupling a magnetic detector with the switching circuit in order to operate the switching circuit to alternatively make and break the circuit connection between the power cord and the current supply responsive to detection of a magnetic element.

Abstract: An improved thermostat having two modes of operation selected by a pressure signal from a central source, which includes a separate set point for each mode of operation. Each set point has a scale which is clearly visible without removal of any parts of the thermostat. Each set point is also adjustable either by an adjuster that can be operated by occupants or only by authorized personnel having a tool fitting the opening in the set point adjustor. Adjustors can be provided with restrictors which limit set point adjustment to a predetermined range of temperatures and which can be adjustable by authorized personnel, or can be factory set.

Abstract: The environmental temperature in an area is controlled by the detection of the presence or absence of personnel in a room. A microphone detects sound in the room and actuates a control circuit to establish a set point for a temperature system which supplies heating and cooling to the room. The presence of people in the room is accompanied by sounds which are detected by the microphone to set the set point at an appropriate temperature to provide a comfortable environment. The absence of sound permits a new set point to be used to reduce the energy consumption of the heating or cooling system. A time delay circuit is optionally incorporated to eliminate undesirable cycling.

Abstract: A timer controlled smoke detecting thermostat has been designed. A control circuit provides for two set point temperatures and time settings for controlling the periods during which one or the other of the set-point temperatures is to be maintained. Means for detecting smoke and sounding an alarm has been built into the thermostat as well as means for inhibiting on states of a controlled heating or cooling unit to prevent air currents in the presence of smoke to reduce the speed at which fire might spread. The thermostat operates on a small leakage current flow through the heating or cooling unit. In addition to supplying power to the thermostat, this leakage current charges a battery so that when full power is applied to the heating or cooling unit and there is no leakage current, power is supplied to the thermostat by the battery. The selection of the temperature to be maintained is made time dependent through the use of an integrated-circuit clock.

Abstract: This invention is for controlling the energization of a furnace, air conditioner or the like that has two thermostats, one to control the upper temperature limit and the other to control the lower temperature limit. A manually settable programming means is provided that is operable on a continuous basis from the voltage across thyristor devices associated with the thermostats which control the on-off condition of the furnace. The programming device devides time into slots and has a switching means that enables a thyristor of a selected one of control paths to conduct when its respective thermostat is closed and to disenable the thyristor of the other control path from conducting in any predetermined time slot. Power for operating the programming device is obtained from the voltage across the thyristors when they are conducting and when they are non-conducting.

Abstract: A set-back control is disclosed which operates relays which are wired in series with heating, ventilating and air conditioning control circuits to effect reduction of energy to maintain building temperatures on a scheduled basis.

Abstract: An integral thermostat and digital clock is disclosed which operates with conventional two-wire systems connected between the thermostat and remotely operated relay. The two wires are used to carry a control signal from the thermostat to the remote relay and power to the integral unit for providing timing signals and power. The integral unit has a combined display which can be used for the time of day or temperature and separate day and night time settings are provided for changing the control of the thermostat according to the users' needs.

Abstract: A two-temperature pneumatic thermostat control system having an output device, a two-level source of pneumatic pressure, a first temperature sensor for controlling the flow of pneumatic fluid from the source to the device when the source is at a first level thereof, a second temperature sensor for controlling the flow of pneumatic fluid from the source to the device when the source is at a second level thereof, a switching unit for automatically switching the device to be controlled by the first sensor when the source is at the first level thereof and by the second sensor when the source is at the second level thereof, and a manual reset member for causing the switching unit to switch the device to be controlled by the first sensor even though the source is at the second level thereof when the reset member is moved to a reset position thereof.

Abstract: An autocycling control circuit unit is provided for controlling heating and/or airconditioning systems to provide controlled comfort and fuel savings. The unit contains a night thermostat which is continually coupled to the system for maintaining a minimum temperature level. A programmable timer enables and disables a day thermostat during settable, predetermined time intervals. The timer includes a feedback circuit for varying the on-off cycling of the day thermostat, after initial warm-up, in accordance with the rate at which the day thermostat calls for heat. The unit contains a backup battery and charger to insure the proper timing sequence in the event of system power outages.

Abstract: A thermostatic controller system for a building heating and/or cooling system (furnace) includes a stored program of desired temperatures which are to be attained within the building at predetermined times within a repetitive time cycle, such as a day. Differing environmental conditions externally of the building result in differing rates of change of temperature within the building upon operation of the furnace. In order to determine the optimum time to switch the system on to meet the next programmed increased temperature, the furnace is switched on and then off a short period of time later and the temperature change which results in the building as a result of that transient operation is measured. The time at which the furnace must be switched to attain the next programmed temperature is then determined as a function of the rate of temperature change as determined by the transient switching and the difference between the instantaneous and the future programmed temperature.

Abstract: A water heater control system is provided to lower the temperature to which hot water is heated during periods of low use, and raise the temperature back up during periods of peak demand. The unit described herein is adapted for use on a recirculating hot water system used in apartment buildings and includes a first thermoswitch disposed on the outflow pipe from the hot water tank which feeds this recirculating system. This pipe is hotter during periods of low use because the heater is adequate to provide continuous supply of very hot water which has not been drained by tenant use. Thus this thermoswitch is directly wired to a thermostat control to reduce the heater temperature when the thermoswitch is hot.

Abstract: A solid state thermostatic device having two programmable temperature control circuits, one of which, when energized, serves to maintain a comfort controlled region at a high temperature level and the other of which, when energized, serves to maintain the comfort controlled region at a lower level. Two clocks are contained within the device for recording real time and for generating an alarm signal when a set time stored in the clock is reached. The two alarm signals generated by the clocks electrically energize the control circuits to regulate the temperature in the comfort control region at the programmed levels during a selected period of time. A digital display is also provided for supplying a visual readout of selected system related parameters including the real time and the stored time contained in each clock and the temperature within the comfort controlled region both in degrees Celsius and Fahrenheit.

Abstract: A night set-back thermostat which may or may not be operable on a two-wire line with one or two series switches and with the possibility for provision of digital time, temperature or other storage and/or data entry or reentry apparatus therefor.

Abstract: The disclosure relates to a system for conserving energy used by temperature regulating units, such as space heaters and air conditioning units, by overriding local thermostatic controls therefor to prevent operation of the units except when a preselected temperature is reached at a master thermostat, the preselected temperature being selected to reduce energy consumption. A seven-day timer and gating circuit enable the overriding of the thermostatic controls during preselected periods of the day, for example during periods when the building is not in use. The system includes a transmitter for transmitting control pulses generated responsively to the timer and master thermostat over the electrical power distribution network of the building.

Abstract: A control system for energizing and de-energizing an external load in series with a source of electricity incorporates a rectifying network having inputs in series with the alternating current source and the external load. An electronic switch of the system activates the load by effectively shorting together the inputs to the control system when the combination of externally sensed parameters obtain predetermined magnitudes. The sensed parameters control the activation of the electronic switch by a plurality of control modules which interact with a control logic module, representing a Boolean combination of the control module outputs, so as to activate a trigger module which in turn causes the electronic switch, such as a silicon controlled rectifier (SCR) to be triggered. The external load is then energized by the SCR effectively shorting the inputs to the control system and which thus completes the electrical path from the source of electricity through the load.