Abstract: A safety device for shutting off the flow of gas to a gas-fired appliance in the presence of flammable vapors. The resistance of a variable resistance flammable vapor sensor is monitored by a microprocessor that controls the operation of a gas flow valve. When the measured resistance indicates the presence of a preselected concentration of flammable vapors, the gas flow valve is shut of and the ignition system cannot be energized.

Abstract: A furnace diagnostic system includes sensors that monitor various functions of the furnace. Data generated by such sensors may be stored for subsequent transfer or may be transferred in real time via an infra red link to a remote handheld device with which an analysis thereof is performed. The handheld device additionally allows the technician to control various furnace functions to facilitate the generation of relevant real time data. In order to further enhance the system's diagnostics capabilities, the communication may be established with a centralized computing facility which includes a data base containing data relating to an entire population of similar furnaces.

Abstract: A single control device is operational to control the flow of gas to a water heater as well as to protect against excessive temperature and pressure. The control device requires only a single fitting to be attached to the water heater tank to expedite the assembly process, eliminate a number of potential sources of leakage and reduce heat loss.

Abstract: A furnace diagnostic system includes sensors that monitor various functions of the furnace. Data generated by such sensors may be stored for subsequent transfer or may be transferred in real time via an infra red link to a remote handheld device with which an analysis thereof is performed. The handheld device additionally allows the technician to control various furnace functions to facilitate the generation of relevant real time data. In order to further enhance the system's diagnostics capabilities, the communication may be established with a centralized computing facility which includes a data base containing data relating to an entire population of similar furnaces.

Abstract: A furnace diagnostic system includes sensors that monitor various functions of the furnace. Data generated by such sensors may be stored for subsequent transfer or may be transferred in real time via an infra red link to a remote handheld device with which an analysis thereof is performed. The handheld device additionally allows the technician to control various furnace functions to facilitate the generation of relevant real time data. In order to further enhance the system's diagnostics capabilities, the communication may be established with a centralized computing facility which includes a data base containing data relating to an entire population of similar furnaces.

Abstract: A furnace diagnostic system includes sensors that monitor various functions of the furnace. Data generated by such sensors may be stored for subsequent transfer or may be transferred in real time via an infra red link to a remote handheld device with which an analysis thereof is performed. The handheld device additionally allows the technician to control various furnace functions to facilitate the generation of relevant real time data. In order to further enhance the system's diagnostics capabilities, the communication may be established with a centralized computing facility which includes a data base containing data relating to an entire population of similar furnaces.

Abstract: A safety device for shutting off the flow of gas to a gas-fired appliance in the presence of flammable vapors. A flammable vapor sensor is inserted in the circuit supplying a solenoid actuated valve with power from a thermocouple. The sensor responds to the presence of a flammable vapor with an increase in resistance. When a critical concentration of flammable vapors is achieved, the voltage drop across the sensor causes the solenoid actuated valve to close.

Abstract: A safety device for shutting off the flow of gas to a gas-fired appliance in the presence of flammable vapors. The resistance of a variable resistance flammable vapor sensor is monitored by a microprocessor that controls the operation of a gas flow valve. When the measured resistance indicates the presence of a preselected concentration of flammable vapors, the gas flow valve is shut of and the ignition system cannot be energized.

Abstract: A water heating system in which the output water temperature is regulated by a mixing valve which allows the temperature of the water contained within the water heater to be maintained at a much higher temperature without compromising safety. Significantly more hot water is therefore available for use yet the maximum temperature supplied to the various points of usage are within the safe limits. The system can be additionally configured to supply unmixed hot water to points of usage where a higher temperature is needed and a user is not exposed to the water such as for example in a dishwasher.

Abstract: A receiver-dryer for use in an air conditioning system utilizes desiccant bags that can be mounted within the receiver-dryer body without using mounting plates or baffles. The receiver-dryer includes an output tube having a retaining shoulder located thereon. In one embodiment, a desiccant bag includes a rigid eyelet that cooperates with the retaining shoulder to support the desiccant bag. In an alternate embodiment, the desiccant bag is supported by the retaining shoulder via a support washer.

Abstract: A parallel flow heat exchanger has perforated webs within its tubes. The tubes are parallel to each other and extend between headers. Each tube has webs located within it which define flow passages. The webs are perforated along the length to communicate refrigerant flow in one passage with that of refrigerant flow in other passages. The flow tubes are extruded integrally. The perforations are formed by air jets mounted in the extrusion die cores.

Abstract: The air conditioner condenser includes a set of hollow parallel tubes disposed between a pair of header pipes. The header tubes provide fluid flow between the header pipes and are substantially flat, having parallel upper and lower side walls. The walls have inner and outer surface and are separated by longitudinally extending webs defining separate flow passages. A partition or baffle is formed by removing one of the upper or lower walls from a tube having a length greater than that of the other tubes. The header pipe has a series of slots, each having similar dimensions. The tubes are inserted into the slots and sealed, with the extended portion of the extended tube forming the partition or baffle.

Abstract: A refrigeration system servicing apparatus includes a digital controller, a vessel for storing and pressurizing refrigerant, a solenoid actuated valve responsive to the digital controller for selective connection of the refrigeration system to a vacuum source, a solenoid actuated valve responsive to the digital controller for connection of the vessel to the refrigeration system, a pressure sensor for providing pressure readings to the digital controller from the low pressure side of the vacuum source, a pressure sensor for providing pressure readings to the digital controller from the vessel and means for quantifying the refrigerant in the Vessel. Three operational modes provided for are: a "vacuum" mode, during which residue material in the refrigeration system is boiled away; a "charge oil" mode, during which lubricant is added to the refrigeration system; and a "charge refrigerant" mode, during which refrigerant is added to a refrigeration system.

Abstract: A refrigerant recovery apparatus has a feature for purging an air conditioning system component for cleaning. The air conditioning component will be connected into the recovery unit at a point where it will receive liquid refrigerant from the recovery unit. This liquid refrigerant comes from the storage container, with pressure being maintained by the use of the compressor. The air conditioning component connects to a purge container, which is separate from the storage container. The purge container has an outlet leading to an expansion valve for converting the purged refrigerant into a vapor. The vapor refrigerant leads back to a suction end of the recovery unit.

Abstract: Two plastic seal plates are located between the end of a manifold and the end of a heat exchanger core having oval shaped flow tubes extending through parallel fins. One seal plate has a plurality of spaced apart oval shaped apertures formed therethrough located to tightly receive the ends of the flow tubes. Oval shaped extension tubes extend from one side of said one seal plate from the oval shaped apertures for tightly receiving the ends of the flow tubes. The other seal plate has a plurality of oval shaped apertures formed therethrough for tightly receiving the extension tubes.

Abstract: A refrigerant recovery apparatus has a combination heat exchanger which both serves as a condenser and evaporator. The heat exchanger has spaced apart headers, each header having a plurality of holes. Finned evaporator tubes and finned condenser tubes extend between the headers. The tubes are parallel to each other and perpendicular to the header. A fan blows air through the evaporator. Refrigerant fluid flows through the condenser and evaporator sections of the heat exchanger. The water condensate formed in the evaporator section will evaporate as a result of the heat from the condenser section. In one embodiment, the evaporator tubes are sandwiched between condenser tubes on the forward and rearward sides of the heat exchanger. In another embodiment, the evaporator tubes are located above the condenser tubes.

Abstract: A refrigerant recovery apparatus has features for trapping oil recovered from an air conditioning system. It has a low pressure oil separator which is mounted in line with the flow of refrigerant on the suction side of the compressor. The low pressure oil separator will be located at a lower elevation than the compressor. When the compressor is turned off, this allows excess oil in the compressor to drain to its design level.