Abstract: A safety shut-off valve opening a flow path between the primary and secondary sides in case of usual operation, while shutting off the aforesaid path in response to an emergency shut-off signal, and particularly such safety shut-off valve cannot be reset unitl it is confirmed that there is no more leakage of gas on the secondary side of the shut-off valve after the shut-off action was once effected, thereby to attaining a very high safeness.

Abstract: In order to protect a boiler against overheating a boiler draft control device comprises a safety thermostat in addition to the regular control thermostat. The control thermostat is provided with a supporting tube in order to limit its length reduction in the event of its failure. The safety thermostat is designed in such a manner that its working element only provides a displacement when the control range of the control thermostat is exceeded. Furthermore the safety thermostat has a very steep displacement/temperature characteristic and its maximum stroke is equal or greater than the stroke being given by an operable control thermostat over its total control range. A latch means is provided to prevent that an air inlet flap closed according to the response of the safety thermostat may be opened again with the cooling down of the boiler.

Abstract: A safety gas valve with latch against non-permitted reopening has the connector of the thermoelectric power unit located on the same side of the housing as the push button of the operating rod which is born shiftable and turnable in the housing. For this purpose, besides a first lever, carrying the closure member and a latch as part of the latching mechanism and cooperating with the power unit, there is provided a second lever which is tiltable around the stationary axis of the first lever. The one end of the second lever engages the armature pin of the power unit, where the other end is positioned opposite an inclined surface of the latch and disengages the latch from the first lever which carries the closure member. In the normal operating position, a projection of the latch keeps the safety valve open. After closing the valve manually, a portion of the latch is located opposite a stationary abutment until the power unit is deenergized after cooling down the thermocouple.

Abstract: A furnace stack damper control apparatus has a motor for connection to a stack damper to open the damper upon a call for heat by a space thermostat. The motor is driven in a closed direction by electrical energization and in an open direction by a spring return. A relay having two normally open switches and a normally closed switch is energized when a space thermostat calls for heat. The normally closed switch then opens to allow the damper motor to open the damper by the spring return. The motor has an end switch having a normally open and a normally closed circuit. The normally open circuit is used with one of the normally open switches of the relay to energize a gas valve when the damper is open. The normally closed end switch is used to provide the energization circuit for the relay by the space thermostat and the relay is maintained energized when the damper is open by the other normally open switch of the relay connected in parallel to the normally closed end switch.

Abstract: In a control system for a gas heated water or air heater, the use of the supplied fuel gas is to be improved by automatically determining and supplying the amount of air which is required for obtaining complete combustion. A gas control valve feeds a burner with the required amount of gas dependent on the demand of heat. A sensor responding to the content of oxygen or carbon dioxide within the flue gases is located in the stack and the output signal of this sensor is compared with a set point within an electric controller. In case of a control deviation, the output signal of the controller controls an adjustable source of air under pressure formed by a fan with subsequent air control valve in such a manner that the required amount of air for reaching optimum combustion is supplied.

Abstract: An integrated control system for a temperature conditioning apparatus which contains a microprocessor which is connected to the various components of a control system of the temperature conditioning apparatus such as the space thermostat, the fuel valve, the fuel igniter and ignition proving apparatus, the stack temperature sensor, the ambient or vestibule temperature sensor, the plenum temperature sensor, the induced draft blower motor, the refrigeration compressor, and the air circulating fan or blower. With the microprocessor, which has the capability of fast and many types of operations, the interaction of parameters of the temperature conditioning apparatus and operation of the various components of the system can be controlled in an improved manner to add to the overall efficiency of such a temperature conditioning apparatus.

Abstract: A thermostat for controlling heating and cooling apparatuses has a temperature control point adjustment knob connected to a temperature responsive switch means for adjusting the control point thereof. A single lever changeover switch is connected to the temperature responsive switch for selectively connecting either heating or cooling apparatus to the temperature responsive switch. Temperature control point limit stops are connected to the temperature control point adjustment. Upon selecting by the single lever changeover switch either a heating or a cooling operation, the temperature control point limit stops limit the movement of the temperature control point adjustment to a first range of movement when heating is selected and a second range of movement when cooling is selected.

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: In an electrical switch being subject to high contact pressure and using contacts of relatively soft contact material, the isolating or electrical resistance is impaired by contact wear. A contact and a counter contact spring supported by an isolating support before and/or behind the contact with an area the surface of which is located lower than the level of the topside of the contact. On at least one side of said recess area, the isolating support is provided with an elevated portion which also extends in the direction of relative movement of the contact spring and on which the contact spring rests when the switch is in its open position.

Abstract: An electronic circuit for eliminating chatter in an output circuit due to contact bounce of switches connected to an input circuit. The electronic circuit has a first and second group of D-flip-flop gates which have outputs for providing a signal to a third group of D-flip-flop gates when triggered by a clock signal when the inputs switch contact bounce has terminated.

Abstract: A time controlled thermostat provides the setting up or setting down of space temperature during certain selected time periods depending on whether it is controlling heating or cooling apparatus as selected by a changeover lever. The normal control temperature as determined by a temperature responsive switch is set by a first selection lever and the setback temperature set by a second selection lever, during heating operation, as selected by the changeover lever the normal temperature is selected by the second selection lever and the setup temperature by the first selection lever during cooling operation as selected by the changeover lever. Limit stops are provided for limiting the position of the first lever during heating to a maximum temperature and the position of the second lever during cooling for a minimum temperature.

Abstract: The present disclosure relates to a load drive control element check circuit for checking whether or not conduction and non-conduction troubles take place in a load controlling switching element at the final output stage of a control device, which is required for safety, such as a combustion control circuit.

Abstract: An integrated control system for a temperature conditioning apparatus which contains a microprocessor which is connected to the various components of a control system of the temperature conditioning apparatus such as the space thermostat, the fuel valve, the fuel igniter and ignition proving apparatus, the plenum temperature sensor, the induced draft blower motor, refrigeration compressor and coil temperature sensor, and the air circulating fan. With the microprocessor, which has the capability of fast and many types of operations, the interaction of parameters of the temperature conditioning apparatus and operation of the various components of the system can be controlled in an improved manner to add to the overall efficiency of such a temperature conditioning apparatus.

Abstract: Apparatus is provided for modifying an open draft hood furnace and its control system, to produce an induced draft furnace having increased efficiency. A blower located in the furnace exhaust stack is used to induce movement of air and combustion products into and through the draft hood. A flow-limiting orifice located in the exhaust stack upstream from the blower causes a region of reduced pressure to exist downstream from the orifice. A pressure signal representative of the flow rate of exhaust stack gases is sensed on the downstream side of the orifice and is communicated by a conduit to a pressure switch connected to a gas valve, which together control gas to the burner. No gas is permitted to flow to the burner unless a predetermined reduced pressure level is achieved at the downstream side of the orifice. A small opening in the conduit permits a small flow of flushing air to enter the conduit.

Abstract: An air conditioning system furnishing temperature conditioned air to a plurality of zones each of which has its own zone damper controlled by its own space thermostat. The system has an air discharge temperature sensor downstream of the temperature conditioning heat exchanger which is connected to a microprocessor controller for controlling a plurality of stages of temperature conditioning apparatus such as heating or cooling apparatus and a damper motor control for controlling the entry of outdoor air into the system.

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: A load management control apparatus with an improved duty cycle operation has a programmed means to control the off time for a selected interval of time for several loads. The total percentage of off time of the loads being controlled is summed and the total integer is used by a sequential operational means to maintain that number of load off at all times even if loads which are off on demand limit control are included to make the number.

Abstract: A room thermostat having an electronic circuit board mounted in a cover and attached to a base member. A space is provided between the back side of the circuit board and the front of the thermostat cover whereby air can pass along the back side of the circuit board to "air wash" for removing heat which is generated by the electrical components mounted on the front side of the circuit board. The front side of the circuit board has a cover over the electrical components for shielding the heat from the components from a temperature responsive element. The temperature responsive element is mounted in a channel provided by the thermostat cover and shield to allow air flow past the temperature responsive means through a channel which includes the space between the thermostat cover and the base.