Abstract: Furnace combustion in a multi-stage or variable input furnace is controlled by operating the furnace in a high fire mode at furnace start-up until the temperature of the products of combustion, or a temperature corresponding to the products of combustion, equals or exceeds a selected temperature. A temperature sensor, preferably a thermostat, is located downstream of the furnace zone of combustion (e.g., in a flue collector box at an outlet from the heat exchanger). The thermostat provides an indication of the products of combustion temperature and has a set point corresponding to the selected temperature. When the products of combustion temperature is less than the selected temperature, the thermostat contacts remain closed. The furnace is operated in the high fire mode while the thermostat contacts remain closed in response to a demand for heating, irrespective of whether the demand is for first stage or second stage heating.

Abstract: The edge seal mechanism of the present invention may be used in connection with clamshell or other formed sheet metal heat exchanger apparatus of the kind utilized for directing hot flue gases into a defined combustion chamber and into various forms of flue passes for radiation from such heat exchanger such combustion chamber. The improved edge seal structure for a clamshell heat exchanger of the present invention includes a first plate flange portion, around which a second flange plate portion is wrapped to define a channel for disposition of the first plate flange portion therebetween. The seal between the first and second flange portion is further formed and stabilized by means of a lateral bend in the first and second flange portions, with such lateral bend being in the direction of and toward the terminal portion of the second plate flange in order to secure maintenance of the seal between the first and second plate flange portions.

Abstract: The improved inshot burner cluster apparatus of the present invention functions to provide combustion of a gaseous fuel and air mixture which is injected through an aperture in the inlet plate into the combustion compartment of a heat exchanger, and includes a burner cluster which may have a selected multiplicity of burners formed from an interjoined upper half shell and a lower half shell. The modular, and essentially clam-shell, form of construction allows for ease of forming the burner elements by embossing the sheet metal half shells, for example using a progressive type of punch press die which can thereafter cut-off any number of burners to form a burner cluster.

Abstract: The present invention relates generally to pulse combustion furnaces, and more particularly to an improved air flapper valve assembly for use in association therewith, such improved air flapper valve assembly having a valve body formed from an elastomeric material which results in significant reduction in air valve sound and vibration.

Abstract: The present improvement is forced air furnaces comprises structure having redisposition of the vestibule panel of a forced air furnace from a location between the flue collector box and the circulating air flow to a location between the inducer motor and the induced draft fan housing. Advantages over prior art structures obtained by such forced air furnace structure having the novel disposition and location of the vestibule panel of the present invention is that the induced draft housing and the flue collector box are then located within the heated and enclosed circulating air flow chamber. One primary advantage of this structure is a significant decrease in noise emitted by the induced draft fan housing, and thus reduction of noise from the forced air furnace as a whole. Moreover, loss of heat from the induced draft housing and the flue collector box are prevented, while more beneficially disposing the inducer motor within the cooler environment of the vestibule area.

Abstract: The improved sectional high efficiency heat exchanger of the present invention comprises apparatus for directing hot flue gases backwardly and into a defined lower combustion chamber. Whereupon, such hot flue gases are directed forwardly in the lower combustion chamber through the upper part thereof. The heated air stream flow is then directed into and to the rear of a lower flue pass, and finally forwardly and to the front of the heat exchanger through an upper flue pass for exiting into a flue collector box. As a result of the above structure, during the burner-"off" cycle combusting gases from the pilot burner are permitted to flow upwardly along the front wall of the lower combustion chamber and into the upper flue passes, thus permitting the heat exchanger to obtain the benefit of the heat energy of the pilot burner gas during the burner-"off" cycle.

Abstract: A furnace comprises a housing, a fan or blower for moving air through housing, a burner in the housing, fuel supply means operatively connected to the burner, a heat exchanger in the housing a combustion chamber, the burner cooperating with said combustion chamber, an enclosure enclosing the heat exchanger and burner, said enclosure having an opening therein, and a damper operable to control the flow of air through said opening to the heat exchanger. The damper comprises a plate member pivotally mounted in the housing for opening and closing said opening. Preferably a drive motor opens the plate member and a spring biases the plate member closed. The damper is closed when the burner is off and is open when the burner is on. There is a circuit associated with the fuel supply means which is responsive to a predetermined open position of the plate member for permitting the flow of fuel through the fuel supply means when the plate member is open to said predetermined open position.