Abstract: A gas burner includes a burner body that defines a plurality of forced induction flame ports. An air outlet orifice is mounted to an injet body at an outlet of an air passage such that the air outlet orifice is oriented for directing a flow of air towards the plurality of forced induction flame ports. A gas outlet orifice is mounted to the injet body at an outlet of a gas passage such that the gas outlet orifice is oriented for directing a flow of gaseous fuel towards the plurality of forced induction flame ports. A pneumatically actuated gas valve is positioned within the injet body. The pneumatically actuated gas valve is configured to adjust from a closed configuration to an open configuration in response to the flow of air through the air passage.

Abstract: A motor controller for a burner system includes an inverter that supplies current to a motor that rotates a draft inducer fan. A processor is coupled to the inverter and receives a signal from a system controller, and in response instructs the inverter to supply a first current, during a first period, to the motor to rotate the fan to produce a first mass flow through the burner system, the first mass flow having a first mass flow rate greater than a threshold to actuate a vacuum switch. The processor then instructs the inverter to supply a second current, during a second period starting at an expiration of the first period, to the motor to rotate the fan to produce a second mass flow through the burner system, the second mass flow having a target mass flow rate for normal operation of the burner.

Abstract: In a gas turbine engine that includes a compressor and a combustor, wherein the combustor includes a primary fuel injector within a fuel nozzle and a secondary fuel injector that is upstream of the fuel nozzle and configured to inject fuel into a flow annulus of the combustor, a method for detecting a flame holding condition about a fuel injector. The method may include the steps of: detecting an upstream pressure upstream of the secondary fuel injector; detecting a downstream pressure downstream of the secondary fuel injector; determining a measured pressure difference between the upstream pressure and the downstream pressure; and comparing the measured pressure difference to an expected pressure difference.

Abstract: Systems, methods, and controllers for controlling gas-fired appliances such as warm air furnaces are disclosed. An illustrative furnace system can include a burner unit in communication with a combustion air flow conduit and heat exchanger, a variable speed inducer fan or blower adapted to provide a flow of combustion air to the burner unit, a furnace controller and motor speed control unit adapted to regulate the speed of the inducer fan or blower, and a pneumatically modulated gas valve adapted to variably output gas pressure to the burner unit based at least in part on the combustion air flow.

Abstract: A method includes the steps of operating a regenerative burner in cycles, including a firing cycle in which fuel and combustion air are discharged from the burner into a process chamber, and a nonfiring cycle in which a quantity of gas is withdrawn from the process chamber through a regenerative bed associated with the burner. The method further includes steps of detecting and responding to a temperature that differs from a predetermined temperature at a location in the process chamber. In a first step of responding to the detected temperature, a flue damper system is operated to vary a flow of gas within the process chamber relative to the location of the detected temperature. A second step of responding to the detected temperature reduces the quantity of gas to be withdrawn from the process chamber through the regenerative bed in a subsequent nonfiring cycle.

Abstract: A gaseous fuel fired furnace having a vapor condensing flue gas vent conduit, a flue gas flow restrictor disposed in the vapor condensing flue gas vent conduit having a flue gas upstream side and a flue gas downstream side, and a condensate bypass conduit extending around the flue gas flow restrictor having a condensate inlet in fluid communication with the flue gas downstream side of the flue gas flow restrictor and a condensate outlet in fluid communication with the flue gas upstream side of the flue gas flow restrictor.

Abstract: A gaseous fuel fired furnace having a vapor condensing flue gas vent conduit, a flue gas flow restrictor disposed in the vapor condensing flue gas vent conduit having a flue gas upstream side and a flue gas downstream side, and a condensate bypass conduit extending around the flue gas flow restrictor having a condensate inlet in fluid communication with the flue gas downstream side of the flue gas flow restrictor and a condensate outlet in fluid communication with the flue gas upstream side of the flue gas flow restrictor.

Abstract: Controlling a modulating gas furnace by monitoring a differential pressure associated with the modulating gas furnace using a low pressure limit switch configured to actuate at a first pressure, an intermediate pressure limit switch configured to actuate at a second pressure, and a high pressure limit switch configured to actuate at a third pressure, the second pressure being between the first and third pressure, selectively operating the modulating gas furnace in one of a cycling mode, a modulating mode in a lower range, and a modulating mode in an upper range, the modulating mode in the lower range being associated with an output capacity range between the output capacity ranges of the cycling mode and the modulating mode in the upper range, and selectively operating the furnace in response to at least one of the low pressure limit switch, the intermediate pressure limit switch, and the high pressure limit switch.

Abstract: A furnace assembly comprising a non-condensing furnace with a draft inducer. The draft inducer includes a permanent magnet electrically commutated motor and a draft inducer blower fan. The motor includes a stator, a rotor, a motor cooling fan, and a controller. The rotor being rotatable relative to the stator, the fan being operatively coupled to the rotor such that rotation of the rotor causes rotation of the fan, the controller being configured to selectively operate the motor in first and second different torque ranges of the rotor, with the first and second torque range operating within a fixed percentage and within a fixed percentage of each other. The controller being configured such during normal operation, the motor is not operable at any torques between the first torque range and the second torque range except during transitionary periods.

Abstract: A damper control system having energy efficient mechanisms. The system may use a heat-to-electric power converter such as a thermopile. Heat may come from a pilot light used for igniting a flame for an appliance. The system may store electric energy in a storage module which could be a sufficiently large capacitor. The system may monitor the position of a damper in a vent or the like and provide start and stop movements of the damper using minimal energy. One way that the system may control electrical energy to a damper motor or another electrical mover of the damper is to use pulse width modulated signals.

Abstract: A forced air furnace may include a pneumatically modulated gas valve that is configured to provide gas to a burner. A pneumatic sampling device may be disposed proximate a combustion blower and may be configured to provide the pneumatically modulated gas valve with a first pneumatic signal and a second pneumatic signal that are representative of fluid flow through the pneumatic sampling device. The pneumatically modulated gas valve may regulate gas flow in accordance with the first and second pneumatic signals. In some cases, the pneumatic sampling device may include a restriction, a first pressure port disposed upstream of the restriction and a second pressure port disposed downstream of the restriction. The first and second pressure ports may provide the first and second pneumatic signals to the pneumatically modulated gas valve.

Abstract: A furnace includes a combustion blower and one or more pressure switches. In some cases, the one or more pressure switches may be used to calculate one or more operating points for the combustion blower. Additional operating points may be calculated by interpolation and/or extrapolation, as appropriate. The furnace may temporarily alter these operating points as necessary to keep the furnace safely operating in response to minor and/or transient changes in the operating conditions of the furnace.

Abstract: Known chimneys or chimney furnaces use flue gas flow units for heating buildings, said devices having displaceable or fixed obstacles for deflecting flue gas for generating flue gas turbulence. The invention relates to a device and method for transferring heat through a flue gas discharge pipe (28) in which (44, 45) pivotal guide plates (37) are inserted in the longitudinal direction of the pipe run, at which the flue gas flow (22) is more or less deflected in a sinuous line as function of the pivot angle (24) of the guide plates (37) that can be adjusted during furnace operation. A fan (19) can increase the flue gas flow (22). An optional furnace heat exchanger (29) generates additional hot water as needed. The controller (5) activates the actuators for the fan (19), guide plate pivot angle setting (24), and at least one circulating pump (10 or 11) as a function of the prescribed controlled variables such as flue gas temperature, reservoir temperature, heat exchanger performance, or flue gas flow.

Abstract: A flame sense circuit and method utilizing only a single pin of a microcontroller is provided. A flame sense circuit is used to vary the charge on a capacitor from a logic high indicating no flame to a logic low when a flame is detected. The microcontroller changes the state of the pin coupled to this circuitry from a high impedance input to detect when the capacitor is discharged indicating the presence of flame, to a logic high output to recharge the flame sense capacitor. Once this charging has been accomplished, the microcontroller again changes the status of the pin to a high impedance input and verifies that the capacitor has been charged. This pin is monitored to verify that the flame sense capacitor is again discharged to indicate the continued presence of flame. This process is repeated to ensure flame continues to be present during a combustion event.

Abstract: The invention relates to a solid-fuel heating apparatus that includes a combustion chamber (1) and a first flue-gas discharge duct (6), characterized in that the heating apparatus includes: a dual wall (2A) defining a second flue-gas discharge duct (2) located outside the combustion chamber and on the flue gas path between the combustion chamber (1) and said first duct (6), and provided in a vertical section thereof with a plurality of controlled communication valves (11, 12, 13, 14, etc.) arranged at respectively different heights (h1, h2, h3, h4, etc.), the second flue-gas discharge duct (2) being adapted via an opening (2B) in the lower portion of the dual wall (2A) so as to extend the flow path of the flue gas by an amount depending on the selection of the open inlet valve in the second duct (2) while the others are closed; adjusting means adapted for selecting, for each of the valves (11, 12, 13, 14, etc.

Abstract: An integrated damper control system is used with a gas fired appliance including a gas burner, a flue and a damper for selectively opening the flue. The damper control system comprises an appliance control including a programmed processor for controlling the gas burner and a communication interface device. A damper control comprises a programmed processor for controlling the damper and a communication interface device for communication with the appliance control communication interface device. The damper control programmed processor is programmed to selectively open or close the damper responsive to status of a damper request register and to control status of a lockout register to indicate status of the damper. The appliance control programmed processor is programmed to control status of the damper request register responsive to a call for operation of the gas burner and to operate the gas burner only if the lockout register is set to unlock.

Abstract: A damper control system having energy efficient mechanisms. The system may use a heat-to-electric power converter such as a thermopile. Heat may come from a pilot light used for igniting a flame for an appliance. The system may store electric energy in a storage module which could be a sufficiently large capacitor. The system may monitor the position of a damper in a vent or the like and provide start and stop movements of the damper using minimal energy. One way that the system may control electrical energy to a damper motor or another electrical mover of the damper is to use pulse width modulated signals.

Abstract: A furnace includes a combustion blower and one or more pressure switches. In some cases, the one or more pressure switches may be used to calculate one or more operating points for the combustion blower. Additional operating points may be calculated by interpolation and/or extrapolation, as appropriate. The furnace may temporarily alter these operating points as necessary to keep the furnace safely operating in response to minor and/or transient changes in the operating conditions of the furnace.

Abstract: A heater including a heat dump opening and a heat dump cover moveable between an open and a closed position to selectively block flow of fluid through the heat dump opening. The heat dump opening is formed in the top of the housing, and the heat dump cover is biased toward the open position. The cover moves to an open position in response to a sensed preselected limit temperature to vent excessively heated air to ambient to prevent damage to the heater and a duct system and a building to which the heater may be connected. Air escaping the heater via the heat dump opening may cause replacement air to be drawn into the heater to cool the heater, including electrical components of the heater located near an inlet and an outlet of the heater.

Abstract: A damper mechanism for a gas-fired appliance is disclosed. The damper mechanism is mechanically operated in response to changes in pressure within a portion of the appliance. Changes in gas pressure operate to displace a diaphragm, thereby moving a linkage attached to a flue damper, such that the damper can be moved between open and closed positions. An interim damper control activation arm can pivot in response to movement of the linkage to actuate electrical switches, which act to close a magnetic pilot valve when the damper is in a partially-opened or partially-closed position.

Abstract: A furnace includes a combustion blower and one or more pressure switches. In some cases, the one or more pressure switches may be used to calculate one or more operating points for the combustion blower. Additional operating points may be calculated by interpolation and/or extrapolation, as appropriate. The furnace may temporarily alter these operating points as necessary to keep the furnace safely operating in response to minor and/or transient changes in the operating conditions of the furnace.

Abstract: A heater including a heat dump opening and a heat dump cover moveable between an open and a closed position to selectively block flow of fluid through the heat dump opening. The heat dump opening is formed in the top of the housing, and the heat dump cover is biased toward the open position. The cover moves to an open position in response to a sensed preselected limit temperature to vent excessively heated air to ambient to prevent damage to the heater and a duct system and a building to which the heater may be connected. Air escaping the heater via the heat dump opening may cause replacement air to be drawn into the heater to cool the heater, including electrical components of the heater located near an inlet and an outlet of the heater.

Abstract: A furnace includes a combustion blower and one or more pressure switches. In some cases, the one or more pressure switches may be used to calculate one or more operating points for the combustion blower. Additional operating points may be calculated by interpolation and/or extrapolation, as appropriate. The furnace may temporarily alter these operating points as necessary to keep the furnace safely operating in response to minor and/or transient changes in the operating conditions of the furnace.

Abstract: The invention includes method and apparatus for controlling the stability of a burner, preferably a low NOx burner, of a natural draft heater. The method includes measuring the draft over a time period and generating a measured output from which a draft function is determined that defines the relationship between the draft and time during the time period. A value for the burner stability is defined that is representative of a stable burner operation. The draft function is compared to the stable burner value to determine a differential value, and the operation of the fired heater is adjusted in response to the differential value. The apparatus includes means for measuring the draft over a time period and means for generating a measured output from which a draft function is determined that is proportional to the cyclic variation of the draft during the time period.

Abstract: Controlling a modulating gas furnace by monitoring a differential pressure associated with the modulating gas furnace using a low pressure limit switch configured to actuate at a first pressure, an intermediate pressure limit switch configured to actuate at a second pressure, and a high pressure limit switch configured to actuate at a third pressure, the second pressure being between the first and third pressure, selectively operating the modulating gas furnace in one of a cycling mode, a modulating mode in a lower range, and a modulating mode in an upper range, the modulating mode in the lower range being associated with an output capacity range between the output capacity ranges of the cycling mode and the modulating mode in the upper range, and selectively operating the furnace in response to at least one of the low pressure limit switch, the intermediate pressure limit switch, and the high pressure limit switch.

Abstract: Methods and systems for operating a fuel fired appliance that may include an optional hardware component such as a damper are disclosed. In some cases, the presence of the optional hardware component is detected, and it is determined whether the optional hardware component is required for future operation of the fuel fired appliance. The fuel fired appliance may be operated normally if the optional hardware component is present and required, or, in some cases, if the optional hardware component is determined to be not required. If the optional hardware component is absent but required, normal operation of the fuel fired appliance may be stopped.

Abstract: A direct sidewall vent system between a fuel-burning appliance in a first space and an external atmosphere, through a wall between the first space and external atmosphere. The direct sidewall vent system has a wall assembly that defines a first passage for communicating combustion gas generated through operation of the fuel-burning appliance to a first outlet through which the combustion gas is communicated to the external atmosphere. The wall assembly further defines a second passage for communicating makeup air from the external atmosphere to the fuel-burning appliance in the first space. The direct sidewall vent system further has an external portion that is situated within the external atmosphere and at which the first outlet is located. The external portion of the direct sidewall vent system has a top, a bottom, and spaced sides.

Abstract: A system to reduce standby losses in a hot water heater is presented. The system utilizes a safety relay valve between the combination gas controller and the burner. The safety relay valve bypasses gas to a damper actuator valve to position a flapper valve located over the flue pipe. Once the flapper valve has opened to ensure combustion, the gas is allowed to flow back to the safety relay valve. Some of the bypass gas may be diverted to boost the pilot or to supply a booster. The safety relay valve is then opened to allow the gas supply to the burner. Once the burner is turned off by the combination gas controller, the small amount of bypass gas bleeds out of the damper actuator valve to close the flapper valve to reduce standby losses through the flue pipe, and to allow the safety relay valve to close tightly.

Abstract: A gas-fired appliance is provided having a burner which is configured to receive and burn pressurized gas, such as natural gas, during operation. A control comprises a pressure switch having an inlet exposed to pressure from the pressurized gas during operation of the burner, a battery, and a motor operatively connected to the battery and the pressure switch which is operated in response to the application of pressurized gas at the inlet. A damper assembly is connected to the motor. The damper assembly comprises a damper movable between an open position and a closed position in response to operation of the motor.

Abstract: A damper mechanism for a gas-fired appliance is disclosed. The damper mechanism is mechanically operated in response to changes in pressure within a portion of the appliance. Changes in gas pressure operate to displace a diaphragm, thereby moving a linkage attached to a flue damper, such that the damper can be moved between open and closed positions. An interim damper control activation arm can pivot in response to movement of the linkage to actuate electrical switches, which act to close a magnetic pilot valve when the damper is in a partially-opened or partially-closed position.

Abstract: A furnace control system for controlling a gas-fired induced-draft furnace having a variable speed inducer blower. A control apparatus, responsive to a signal corresponding to the magnitude of a pressure difference between an inlet and outlet of the combustion chamber, controls blower motor speed to maintain the pressure difference at a predetermined magnitude corresponding to a selected gas flow rate. Inducer blower motor speed is varied directly and precisely to maintain an optimal pressure drop across the combustion chamber. The control system can be used in multi-stage and modulating furnace systems and in furnace systems utilizing pressure-assist modulating gas valves.

Abstract: A draft inducer system has a voltage reducer capable of converting an input AC voltage to a reduced voltage, and an inducer unit capable of being coupled with the voltage reducer. The voltage reducer includes a reducer housing, a set of prongs extending from the reducer housing, and an output interface capable of delivering the reduced voltage. The set of prongs is capable of plugging into an AC outlet. The inducer unit has a unit housing, an air moving device within the unit housing, and a mixing chamber formed by the unit housing. The mixing chamber has an exhaust input to receive exhaust from a burning fuel, and an ambient air input for receiving ambient air. The ambient air mixes with the exhaust in the mixing chamber to produce mixed air. Accordingly, the mixing chamber also has a mix output capable of directing the mixed air from the mixing chamber.

Abstract: A compact, highly flexible and efficient, multi-positionable, multi-dimensional and multi-stage gas-fired heat exchanger system as described. The system is connectable in a forced air duct regardless of the angular position and size of the duct. The heat exchanger comprises one or more heat transfer tubes which are shaped and dimensioned as dictated by the customized use of the heat exchanger. The tubes are secured to a support panel as well as the gas burner associated with each of the inlet openings of the tubes. A position orientable gas valve is secured to a gas distribution manifold. A turbulator may be associated with at least some of the tubes to cause turbulence in the hot combustion flow in each of the tubes to modify the efficiency in heat transfer along one or more sections of the tubes by directing hot combustion gas along an inner circumferential wall of the tubes.

Abstract: A damper control device is disclosed comprising a mounting plate, a motor assembly coupled to the mounting plate and having a shaft extending therefrom, and a single circuit board coupled to the mounting plate, comprising relay control circuitry which rotates the shaft to an open position in response to a first signal, rotates the shaft to a closed position in response to a second signal, and time delay circuitry which holds the shaft in the open position for a period of time after receipt of the second signal. Preferably the damper control device can be used with an oil-fired heating appliance.

Abstract: A device for controlling a damper in an appliance is disclosed comprising a motor having a rotatable shaft extending therefrom which is operatively connected to a plate of the damper, a control circuit which transmits current to the motor to rotate the shaft and in turn rotate the plate to a first position and to a second position, and a dynamic brake operatively connected to the motor, which acts to reduce rotation of the shaft when the circuit supplying current to the motor is opened.

Abstract: A device for controlling a damper in an appliance is disclosed comprising a motor having a rotatable shaft extending therefrom which is operatively connected to a plate of the damper, a control circuit which transmits current to the motor to rotate the shaft and in turn rotate the plate to a first position and to a second position, and a dynamic brake operatively connected to the motor, which acts to reduce rotation of the shaft when the circuit supplying current to the motor is opened.

Abstract: A damper control device is disclosed comprising a mounting plate, a motor assembly coupled to the mounting plate and having a shaft extending therefrom, and a single circuit board coupled to the mounting plate, comprising relay control circuitry which rotates the shaft to an open position in response to a first signal, rotates the shaft to a closed position in response to a second signal, and time delay circuitry which holds the shaft in the open position for a period of time after receipt of the second signal. Preferably the damper control device can be used with an oil-fired heating appliance.

Abstract: An improved furnace including a two-speed inducer motor which can be used as a single speed motor for either a vertically or horizontally vented furnaces. The inducer has a common terminal, a low speed terminal and a high speed terminal. One lead is attached to the common terminal and, depending on whether the furnace is vented horizontally or vertically, either the high speed or low speed terminal is used. If the furnace is vented vertically, one lead is connected to the common terminal and the other lead is connected to the low speed terminal. Thus the furnace operates at a low speed when the furnace is vented vertically. If the furnace is vented horizontally, one lead is connected to the common terminal and the other lead is connected to the high speed terminal. Thus, the inducer motor operates at the higher speed when the furnace is vented horizontally.

Abstract: A device for controlling a gas-fired appliance is provided. The device includes a motor assembly having a shaft extending therefrom and a cam coupled to the shaft for rotation therewith. The cam is coupled to a damper plate of the gas-fired appliance and the plate is configured to rotate with the cam responsive to rotation of the motor shaft. The device further includes a printed circuit board having a control switch mounted thereon. The cam is configured to selectively actuate the control switch upon rotation of the cam. The inventive control device may also include a mounting plate to which the motor assembly and circuit board may be mounted. The mounting plate may be an injection-molded, plastic part. In accordance with the present invention the cam is supported on the printed circuit board as opposed to the mounting plate thereby ensuring an accurate positional relationship between the cam and the control switch.

Abstract: Pressure sensing device in a gas furnace including a first tube in communication with a position of an air supply pipe on an inlet side of an air supply fan having a pressure identical to an inlet of the air supply fan, a second tube in communication with a position of an air supply pipe on an outlet side of the air supply fan having a pressure identical to an outlet of the air supply fan, and a pressure difference sensing means respectively connected to the first and second tubes for providing an electric signal according to a pressure difference caused by pressure on the first and the second tubes, thereby detecting clogging states both of the air supply pipe and the exhaust gas pipe, and method for controlling operation of a gas furnace, including the steps of (1) a pressure difference sensing device providing an electric signal according to a pressure difference between inlet/outlet of an air supply fan during operation or a pre-purge step for starting operation, (2) comparing the electric signal to a pre

Abstract: A furnace is provided with a flame rollout protection system which operates through an existing excess-air control pneumatic circuitry to shut down the furnace in the event of a flame rollout condition. A fusible tube is attached at its one end to the pneumatic system and extends into an area which will be exposed to hot gases in the event of a flame rollout condition. A melting of the tube by the hot gases causes the pressure therein to drop to ambient pressure such that of the pneumatic circuitry responsively causes the furnace to shut down. The tube is also extended to pass through an area which will be exposed to hot gases in the event of a blocked vent in the furnace, thereby causing a similar shut down of the furnace.

Abstract: A method for controlling kiln pressure for a shuttle kiln having an exhaust gas fan and an exhaust gas damper in an exhaust gas passage includes the steps of performing a control operation for controlling the number of revolution of the exhaust gas fan to control flow rate of the exhaust gas to maintain the kiln pressure at a predetermined pressure, and performing a control operation for adjusting opening of the exhaust gas damper based on the number of revolution of the exhaust gas fan. The method can expand the control range of exhaust gas flow, and operation with energy saving efficiency can be performed.

Abstract: A device for controlling a gas-fired appliance having a thermoelectric device such as a thermopile is provided and, particularly, for controlling a damper and a main burner valve within a gas-fired appliance. The device includes a motor having a shaft extending therefrom for connection to a plate of a damper. The device further includes a control circuit that selectively transmits current from the thermoelectric device to the motor and to the main burner valve of the appliance. The control circuit includes a temperature sensor and a plurality of single pole double throw switches. When the temperature sensor determines that the temperature of a medium such as water or air is below a predetermined temperature, current is directed through the switches to the motor in order to open the damper. Once the damper is opened, current is redirected through the switches to the valve to open the valve.

Abstract: An orifice is disposed in an intake tube for developing a pressure difference across the orifice, i.e., portions of the intake tube which are positioned upstream and downstream of the orifice. An upstream connection pipe and a downstream connection pipe have respective ends connected to the intake tube and opening into the intake tube respectively upstream and downstream of the orifice, and respective opposite ends connected to a pressure sensor. The pressure sensor detects the pressure difference between the pressure of combustion air in the upstream connection pipe and the pressure of combustion air in the downstream connection pipe.

Abstract: A combustion air regulating apparatus which is adapted for use with two stage induced draft furnaces and which allows such furnaces to be used with low cost AC inducer motors of the type having one or a small number of nominally fixed operating speeds. A flow restrictor assembly is disposed in fluidic series with the air intake and the exhaust vent to controllably restrict the flow of air through the burner box when the inducer motor operates at its low speed. A pressure sensing assembly is connected to sense a pressure approximately equal to that across the heat exchanger, and to control the flow resistance of the flow restrictor assembly to maintain a sufficient level of excess air when the furnace operates in its low stage. A solenoid valve responsive to the establishment of high stage furnace operation causes the flow restrictor assembly to establish and maintain its minimum flow resistance during operation in that stage.

Abstract: A method for controlling an igniting operation for a gas boiler for preventing an explosive ignition is disclosed. The gas boiler is equipped with a burner for burning a gas, a fan for exhausting a burnt gas in the burner, and an ignition plug for performing igniting operation of the gas supplied into the burner. If the operation of the gas boiler commences, the gas is supplied into the burner while the exhaust fan is operated at a low speed appropriate for performing the igniting operation, and the ignition plug is operated to perform the igniting operation of the gas in the burner. In that situation, if ignition does not occur during a predetermined time, the rotational velocity of the exhaust fan increases, whereby the density of gas in the burner is maintained constant. Thus, the excessive increasing of the gas density is prevented, so the explosive ignition is prevented.

Abstract: An apparatus for detecting a head wind in a gas boiler and method is disclosed which is capable of the magnitude of variation of voltage corresponding to the R.P.M. of an exhaust fan and the combustion state of flame. A microcomputer in the gas boiler detects the R.P.M of exhaust fan and voltage applied to the exhaust fan when the R.P.M exceeds a normal limit. The detected voltage is compared with a reference voltage. If the compared result exceeds a predetermined value, to sense the combustion state of flame an infrared rays sensor is used. When the head wind is introduced into an exhaust conduit, the red wavelength is sensed at flame due to incomplete combustion. Accordingly, in case that the magnitude of variation of voltage exceeds a predetermined value and the red wavelength is sensed, microcomputer can detect the head wind.

Abstract: A furnace control apparatus is described wherein a flow of gas into a burner assembly is directly dependent on an indicia of burner combustion air airflow, such as heat exchanger pressure drop. According to one embodiment of the invention, a first communication fluid line is interposed between a gas valve regulator and a heat exchanger at a first point, and a second communication fluid line is interposed between a gas valve regulator a heat exchanger at a second point. The main valve of the gas valve is responsive to the pressure differential between the first and second points so that a flow of gas into a furnace burner assembly is commensurate with a present flow level of combustion air.

Abstract: A control system for regulating a flow rate of a heat transfer fluid in a heat transfer system, the heat transfer system having a heat transfer fluid flow path, flow control device for creating flow along the path, a fuel source for providing a combustible fuel to the path, an air source for providing combustion air to the path, and an assembly for combusting the fuel and air, the control system comprising a sensor for sensing a measured flow value at the air source, a controller for storing an optimum flow value at the air source and for storing a range of operating control values for the flow control device, the operating control values corresponding to the optimum flow value, a system for calculating a deviation between the measured flow value and the optimum flow value, and a system for varying the operation of the flow control means in accordance with the deviation.

Abstract: Method and apparatus for maintaining even heat distribution to each of the tubes contained in a down-fired induced draft furnace by eliminating external atmosphere disturbances such as wind from influencing furnace operation. The top of the furnace is isolated from receiving ambient air except through a central path which controls both rate and direction of air flow.