Abstract: A conventional watchdog timer circuit is arranged to judge a microcomputer to be normal as long as a pulse signal is being outputted from the microcomputer. Therefore, an abnormal condition cannot be detected when an operating frequency of the microcomputer lowers, for example. As a solution, the watchdog timer circuit is provided with a function for detecting the frequency. If the frequency of the pulse signal deviates from a predetermined frequency range, a reset signal is outputted indicating that the microcomputer is abnormal, even if the pulse signal is being outputted. A solenoid-operated gate valve is thereby closed to stop the supply of gas to a gas burner.

Abstract: A heating or cooling system, such as an HVAC system, of variable output has a number of control elements and may include a variable speed compressor, a variable speed combustion (induced or forced draft) blower motor; a variable speed circulator blower motor; a variable output gas valve or gas/air premix unit; and a controller specifically developed for variable output applications. The system may utilize a pressure sensor to determine the actual flow of combustion airflow in response to actual space conditions, vary the speed of the inducer blower, and subsequently vary the gas valve output to supply the correct amount of gas to the burner system. A temperature sensor may be located in the discharge air stream of the conditioned air to provide an input signal for the circulator blower.

Abstract: A method for setting the performance of a gas operating cooking device by setting a complete combustion of the fuel gas/air mixture supplied to the gas burner of the cooking device.

Abstract: The system for active regulation of the air/gas ratio of a burner comprises one or two differential pressure measuring systems each of which has a differential pressure sensor with two inlet orifices. The orifices are respectively connected to pressure ports in one of which there is a calibrated throttling orifice. The regulator system comprises a 2-channel valve which, when closed, isolates the two inlet orifices from each other, and, when open, connects them to each other. A measurement circuit is provided and has memory means for storing at least two values of the output signal of the sensors, a control unit for switching the valve and controlling the storage of a first value of an output signal of the sensor in the memory means when the valve is closed and the storage of a second value of the output signal of the sensor when the valve is open, and subtractor means for calculating the difference between the two stored values of the output signal of the sensor and thereby eliminating any drift.

Abstract: An improved gas appliance having a burner, a gas valve through which the flow of combustion gas to the burner is controlled, and a motor driven blower that supplies combustion air to the burner. The improvement includes means for increasing gas flow through the gas valve as blower speed increases, and decreasing gas flow through the gas valve as blower speed decreases, based on a pressure signal generated independently of combustion air pressure. This improvement allows a constant ratio of gas to air to be maintained in the burner while a combustion flow rate varies dependent on the blower motor revolutions per minute. Thus input pressures of combustion can be controlled at low cost.

Abstract: A direct gas-fired industrial air heater low fire start control, includes circuitry for simulating a resistant circuit which bypasses the discharge temperature sensors, the remote temperature selector, and a space temperature controls, that has the effect of driving the modulating valve to a fixed open setting which in turn changes the valve voltage in order to obtain desired gas flow. In a further embodiment, an isolated DC voltage source which normally bypasses the voltage input to the system of the modulating valve can be inserted into the circuitry to effectively drive the modulating valve to a fixed open setting to obtain the desired gas flow rate. Various circuitry, and bypass gas flow arrangements, are further shown to increase the efficiency of ignition of the burner assembly, when started.

Abstract: A gas burner operating system includes a control unit installed in the body of a gas burner and connected to an electronic igniter in the body of the gas burner, the operating unit using a cock, a pressure differential device, a medium flowrate control valve and a low flowrate control valve to control the operation of the gas burner and the intensity of the burner flame, and an operating unit provided outside the body of the gas burner for enabling the user to control the operation of the control unit and the electronic igniter of the gas burner at a remote place away from the gas burner.

Abstract: An oil burner control system is disclosed in which an extended time may be temporarily selected, in situations such as initial set up or periodic maintenance, for priming the pipes, filters and pumps, before a safety lockout of system operation occurs, while otherwise leaving the normal safety lockout functions intact. An igniter in the system operates in an “intermittent” mode during the temporarily selected extended time, and otherwise operates in an “interrupted” mode.

Abstract: An ignitor controller and method of providing the same triggers an ignitor switch of a gas appliance, such as a furnace, subsequent to the zero-crossing of the line voltage, but before the voltage exceeds +/−five volts. This effectively reduces EMI levels caused by the constant triggering of AC line voltage to the ignitor switch after +/−five volts, which constant triggering is needed to properly operate ignitors (e.g., silicon nitride ignitors) in electronic ignition systems. The controller includes a voltage detector circuit (i.e., a two transistor circuit), a series switch (i.e., a darlington array) and an energy storage device (i.e., a capacitor), which trigger the ignitor switch (e.g., a triac) sufficiently close to the line voltage zero-crossing to reduce line conducted interference.

Abstract: A miniature heat source capable of being used in a hand-held device for delivering a metered pulse of fuel to a combustion chamber where it is converted into a pulsed amount of heat. For example, the heat source apparatus can be used in a hand-held cigarette smoking system or within a portable device wherein a microturbine generates electricity, as well as any type of environment where a high energy pulse of heat is desired. The heat source includes a valve such as a sliding, rotatable or timed valve which delivers a metered volume of fuel to the combustion chamber. The valve can deliver the fuel, in an expanded gaseous form, to a venturi conduit which increases the velocity of the gas flow, and delivers the fuel to a combustion chamber where the gas is mixed with air. The combustible mixture is then combusted within the combustion chamber by ignition and/or by catalyzed oxidation.

Abstract: When an error occurs to a combustion device, a microcomputer inside a control apparatus for the combustion device closes a safety valve thereby stopping gas supply to a gas burner. In a conventional control apparatus, when a power source resetting is actuated with a power switch, the safety valve is opened to supply the gas burner with gas even though the cause for the error has not been resolved. As a solution, when an error occurs, the fact of such an occurrence is stored in a nonvolatile memory, i.e., electrically erasable programmable read-only memory, EEPROM. It is so arranged that, unless the reset switch is operated, the memory in the EEPROM is not reset. After resetting, the memory in the EEPROM is read out. As long as the reset has not been made, the safety valve is not opened, but the program immediately proceeds to a state in which the operation of the reset switch is held in suspension.

Abstract: A method for decreasing the concentration of a chlorinated aromatic compound in the exhaust gas from a combustion furnace. The exhaust gas from the combustion furnace is passed through a bag filter. The concentration of the chlorinated aromatic compound in the exhaust gas is measured and the operating temperature of the bag filter is adjusted based on the measured concentration of the chlorinated aromatic compound in order to decrease the concentration of the chlorinated aromatic compound in the exhaust gas.

Abstract: An apparatus for and method for providing easy and rapid conversion from a first fuel to a second fuel in a gas appliance. The gas appliance has a variable fuel valve controlled by a microprocessor. A table stored in non-volatile memory has an entry for each of the fuels to be burned in the gas appliance. The table entries are empirically determined at the time of manufacture.

Abstract: A programmable burner for gas stoves, which is constituted by a gas burner and a safety valve that includes a thermocouple, which is located in coincidence with an external edge of the burner. The safety valve is maintained open when the thermocouple is detecting the presence of a flame on the gas burner and is closed when the burner has been turned off. An electrode is placed near of the external periphery of the burner for igniting. A spark generation module is connected with the electrode for generating the sparks for igniting the burner. A spark interrupter is connected to the spark generation module, the spark interrupter being located over a burner knob that is connected to the safety valve, for activating or deactivating the spark generation of the spark generation module. Finally a programmable device is connected with the thermocouple and the security valve, for programming the ignition time of the burner in accordance with a preestablished operation time by user.

Abstract: A gas furnace control arrangement includes a control unit control unit and an operating unit adapted to control the control unit, the control unit having a valve seat holding a set of solenoid valves, the solenoid valves including a main valve for fuel gas input control, a mother flame valve adapted to control a gas passage from the valve seat to a mother flame nozzle, a high flow rate valve and a medium flow rate valve and a low flow rate valve adapted to control a respective gas passage from the valve seat to a main flame nozzle, the operating unit including a power switch adapted to switch on/off an electronic igniter and to close/open the main valve and the mother flame valve, a strong flame switch adapted to close/open the high flow rate valve, a medium flame switch adapted to close/open the medium flow rate valve, and a weak flame switch linked to the strong flame and the medium flame switch and adapted to close/open the low flow rate valve.

Abstract: The invention relates to a flame monitor for an oil- or gas-operated burner, having a photosensor which detects the optical flame radiation and an evaluation circuit which is connected downstream of said photosensor and ascertains whether the radiation received by the photosensor corresponds to that of a burning flame and, in the event of a negative result, generates a switch-off signal for the fuel supply, wherein the evaluation circuit determines the number of zero crossings of the processed signal of the photosensor within a predetermined unit of time and compares it with a predetermined limit value, a switch-off signal for the fuel supply being generated when said limit value is undershot, the signal of the photosensor, freed from the DC voltage component and noise, being processed by corresponding amplification to form square-wave pulses.

Abstract: In a combustion unit, a fuel collision member is disposed between a fuel injection valve and a combustion chamber. The fuel collision member is positioned so that, a part of fuel injected from said fuel injection valve is introduced into the combustion chamber while colliding with the fuel collision member, and the other part of fuel is directly introduced into the combustion chamber without colliding with the fuel collision member. Thus, fuel introduced into the combustion chamber is atomized while being introduced into the combustion chamber in a wide range.

Abstract: Combustion variables are diagnosed using sensors to measure turbulence in the post-flame zone as well as in the flame envelope of a combustor. Output signals from the sensors are processed and a set of statistical functions are calculated which are correlated with specific combustion variables, such as the concentration of unburned carbon in fly ash. A special sensor mounting box provides reliable long-term operation in harsh combustor environment, without a supply of cooling or protective air flow.

Abstract: A conventional watchdog timer circuit is arranged to judge a microcomputer to be normal as long as a pulse signal is being outputted from the microcomputer. Therefore, an abnormal condition cannot be detected when an operating frequency of the microcomputer lowers, for example. As a solution, the watchdog timer circuit is provided with a function for detecting the frequency. If the frequency of the pulse signal deviates from a predetermined frequency range, a reset signal is outputted indicating that the microcomputer is abnormal, even if the pulse signal is being outputted. A solenoid-operated gate valve is thereby closed to stop the supply of gas to a gas burner.

Abstract: A method of controlling a variable speed draft inducer motor and fan in a gas furnace. The method comprises the steps of: detecting a first fault driving the motor to a maximum operating range; detecting a second fault forcing the motor to operate towards a minimum operating range; and generating a fault signal if both faults are detected substantially simultaneously.

Abstract: When an error occurs to a combustion device, a microcomputer inside a control apparatus for the combustion device closes a safety valve thereby stopping gas supply to a gas burner. In a conventional control apparatus, when a power source resetting is actuated with a power switch, the safety valve is opened to supply the gas burner with gas even though the cause for the error has not been resolved. As a solution, when an error occurs, the fact of such an occurrence is stored in a nonvolatile memory, i.e., electrically erasable programmable read-only memory, EEPROM. It is so arranged that, unless the reset switch is operated, the memory in the EEPROM is not reset. After resetting, the memory in the EEPROM is read out. As long as the reset has not been made, the safety valve is not opened, but the program immediately proceeds to a state in which the operation of the reset switch is held in suspension.

Abstract: A first object of the invention is to provide a control circuit (1) for gas burners with a fail-safe system. The circuit (1) includes a microcontroller (2) that acts on at least one valve (4), flame detector circuits (50) and tap opening detector switches (6). For each valve (4) the circuit (1) has a plurality of switches by means of which these valves are supplied with the voltage required to open them and keep them open. The microcontroller (2) governs said switches in accordance with the signals it receives from the circuits (5), from the switches (6), and from points of the actual circuit (1). The circuit (1) is safe against the failure of any of its components, including the microcontroller (2). A second object of the invention is also to provide a circuit (1) that has protection against a double failure.

Abstract: A method of controlling a variable speed draft inducer motor and fan in a gas furnace. The method comprises the steps of: detecting a first fault driving the motor to a maximum operating range; detecting a second fault forcing the motor to operate towards a minimum operating range; and generating a fault signal if both faults are detected substantially simultaneously.

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 draft safeguard apparatus for use in a multi-poised furnace having an inducer housing for receiving flue gases from a heat exchanger. The furnace flue pipe is attached to the inducer housing by an elbow having a first linear inlet section that is rotatably connected to the inducer housing and a second linear outlet section that is connected to the flue pipe. A bend section connects the inlet and outlet section of the elbow. An elongated sensor housing is mounted upon the inlet section of the elbow. The housing provides a flow channel so that the inlet section of the elbow communicates with the surrounding ambient. A limit switch is mounted in the housing to sense the temperature in the flow passing through the housing. When the furnace is operating normally, ambient air is drawn into the vent system through the sensor housing. If the vent system becomes restricted, the flow through the housing is reversed and the limit switch is opened when the reverse flow temperature exceeds a given limit.

Abstract: A device for igniting fuel, comprising at least one burner, the device comprising ignition means comprising an ignition element, the ignition means further comprising a movable element which is connected to a fluid line, such that a fluid contained in the fluid line, when it flows, creates a pressure difference across the movable element, as a result of which the movable element is set in motion, the movable element being connected with the ignition element, such that the movement of the movable element generates via the ignition element an ignition temperature by means of which the fuel is caused to combust.

Abstract: An improved, induced-draft, gas-fired furnace which is adapted to operate at any of a high, medium and low firing rate. A pressure sensing assembly generates differential pressure signals that vary in accordance with the pressure across a heat exchanger assembly. A gas flow control assembly is responsive to the differential pressure signals, and to signals received from the furnace control circuit, to supply gas to the furnace at any of its three different firing rates, the lowest of those firing rates corresponding to a gas-air mixture which cannot be ignited. The furnace control circuit applies to the circulating air blower, and to the inducer blower, speed control signals that are so related to one another that the lowest primary wall temperature in the heat exchanger is maintained above the condensation temperature of water during steady state operation of the furnace at its low firing rate.

Abstract: The burner system (17) includes a burner (28), an air/fuel supply, and a burner control (12) that includes a pair of valve assemblies (13,14) with a flow control (18) and two valve actuators (10,11). A position encoder (108) is rigidly connected to the flow control member (18) and generates valve position signals. Control modules (112 are programmed to drive and store calibration parameters specific to the position encoder (108). During operation, the control modules command positioning of the flow control member (18) and compare the position signals to the stored positions to determine correct valve position.

Abstract: A burner system for use in applications such as a gas fireplace insert has a main burner, a standing pilot burner, a burner control unit, and a fuel valve. In one embodiment, the fuel valve and burner control unit receive power from a power source such as a thermopile mounted to receive energy from the pilot burner. The burner control unit includes a switch controlling power to the fuel valve and a RF receiver. The RF receiver controls the opening and closing of the switch responsive to encoded RF signals transmitted to it by a remote transmitter.

Abstract: A method of controlling a variable speed draft inducer motor and fan in a gas furnace. The method comprises the steps of: detecting a first fault driving the motor to a maximum operating range; detecting a second fault forcing the motor to operate towards a minimum operating range; and generating a fault signal if both faults are detected substantially simultaneously.

Abstract: A method and apparatus for increasing the circulating airflow of induced-draft, gas-fired multi-stage furnaces without creating conditions that result in cold spot corrosion therein. Control circuitry is provided to selectably increase the circulating airflow of the furnace during low stage operation. The control circuitry is arranged so that increases in the magnitude of the circulating airflow of the furnace are accompanied by predetermined increases in the magnitude of the combustion airflow of the furnace. The magnitudes of the circulating and combustion airflows are so related to one another that the temperature at the output of the heat exchanger is maintained at a value which is approximately constant, and which is high enough to assure that water cannot condense thereon. The control circuitry may include a relay or relay-like device that is connected to prevent the high stage solenoid of the gas valve from becoming actuated during low stage operation.

Abstract: A gas turbine includes a compressor for compressing air and discharging compressed air. A combustor produces a hot gas by burning a fuel having a quality level in the compressed air. A turbine expands the hot gas produced by the combustor. A fuel delivery system delivers the fuel to the combustor. A fuel quality sensor senses the quality level of the fuel which is delivered to the combustor. A control and monitoring system stops delivery of the fuel as a function of the quality level, and stores a history of the quality level.

Abstract: A combustion system includes a combustion chamber. A fan is connected to the combustion chamber. The fan has a spin velocity. A burner is adjacent the combustion chamber. The burner defines one or more flame openings. Each flame opening has a cross section. An obstacle is associated with each of the one or more flame openings. Each obstacle is within the combustion chamber. A mixture of fuel gas and air having a mixture temperature is discharged at a discharge velocity from the one or more flame openings. A flame is positioned along the burner substantially detached from the one or more openings. A flame position sensor senses the position of the flame and generates a flame position signal based on the sensed position of the flame. A control processor maintains the flame around a prefixed optimum position by controlling a characteristic variable quantity of the mixture based on the flame position signal.

Abstract: A pilot burner assembly for a gas burning heater which has a pilot fuel supply pipe and a pilot burner head with an inner chamber defined by a generally continuous sidewall. The pilot burner head has a middle body region with a side port defining a channel passing through the sidewall which has a channel wall. An ignitor rod passes at least partially into the port and terminates at an ignitor tip which is adapted to provide electrical current between the ignitor tip and the sidewall to ignite a pilot flame. A boss is welded on the burner head and surrounds the port. An insulation sleeve is positioned within the boss and has a central aperture adapted to allow passage of the ignitor rod and maintain the ignitor rod in position. A pilot flame sensor is positioned adjacent the pilot burner head and adapted to indicate the ignited pilot flame to a computerized control means.

Abstract: A fuel/air mixture control for an induction heater having a tube-type burner includes a side-venting fuel nozzle for introducing fuel into an induction air stream entering the burner. A multi-speed blower draws combustion air into the burner and an air flow constrictor disposed proximate the fuel nozzle increases the velocity of the induction air stream proximate the fuel nozzle, increasing the volume of fuel introduced into the burner conduit. The fuel/air mixture depends upon the speed of the blower, which can be thermostatically controlled to increase speed upon sensing higher temperature combustion products, thereby maintaining a steady mass air flow and air/fuel mixture.

Abstract: A direct ignition type pulsated combustion apparatus including a burner provided in a combustion furnace, a combustion air line connected to the burner for feeding combustion air to the burner, a fuel gas line connected to the burner for feeding a fuel gas to the burner, an air valve and a fuel valve provided in the combustion air line and the fuel gas line, respectively. A plurality of actuators provided for the air valve and the fuel valve are adapted to open and close the air valve and the fuel valve, respectively. An air bypass line is provided in the combustion air line to bypass the air valve. A fuel bypass line provided in the fuel gas line for bypassing the fuel gas valve. A control unit actuates the opening/closing cycles and timings of the air and the fuel gas valves connected to the actuators, respectively, allowing the cycle time of opening and closing the air valve to be controlled independently of the cycle time of opening and closing the fuel gas valve.

Abstract: The present invention relates to a method for controlling thermal processes, whereby measuring devices measure at least two process parameters at least once within a time interval in which a parameter change occurs that is not negligible for the process sequence, the recorded parameters are fed into a control unit, and the control unit regulates the process parameters in the thermal process by means of quantities obtained from the measurements of process parameters.

Abstract: A modulated burner combustion system that prevents the use of components that were originally not commissioned for use in the system. The present invention uses actuators that contain unique stored identification numbers. When the system is initially configured or commissioned, the unique identification numbers of the actuators are stored in nonvolatile memory in a fuel/air controller. When the system is brought on line, the fuel/air controller microprocessor initially sends false IDs to the actuator together with test control signals to determine if the actuator operates in response to the false identification numbers. If the actuator does operate in response to the false identification numbers, that is an indication that the system has been tampered with and the system is, consequently, shut down. Subsequently, the true identification numbers are transmitted to the actuators with test control signals.

Abstract: A gas burner assembly (10) and method for providing combustion air flow and gas fuel flow in linear proportion to a control signal. A blower motor (18) is driven by the control signal and drives a blower (14) whose output (16) has a static pressure proportional to the square of the blower speed. A gas fuel controller 28 is responsive to the static pressure of the blower output (16) to meter fuel in proportion to the square root of that static pressure.

Abstract: A gas burner operation monitoring apparatus for enabling convenient diagnosis of gas burner and control problems. The invention is a temporarily attached device that collects and stores information concerning the key functions indicative of a gas burner's operation. If a fault occurs, the apparatus generates a signal to indicate to a downstream microprocessor, if such is connected, that a problem has occurred. This eliminates the need for the technician to randomly replace parts until the problem is located. The system monitors the status of the thermostat or aquastat; the presence and the level of voltage being sent to the main gas valve; the pressure of gas at the inlet and outlet of the main gas valve and either the temperature on the outside of the vent stack pipe or the presence and quality of flame at the main gas burner. The device also provides a signal in the event of a fault that can be connected to a downstream microprocessor that, in turn, can activate various warning devices.

Abstract: Apparatus provides an air/fuel mixture to a fully premixed burner (4) and comprises a fuel line for providing fuel to the burner (4) a fan for supplying air at a variable flow rate to the fuel to form the mixture, a sensor (30) for sensing aeration of the fuel combustion products and a controller (26) for controlling the air flow rate in dependence upon the aeration sensed in such a way that the air flow rate is sufficient to maintain the aeration at or close to a predetermined value, the controller, in use, maintaining the air flow rate at one of a number of differing predetermined values which are in the form of a geometric series characterized by a constant value of the ratio between successive values.

Abstract: A gas light assembly having an electronic control system that monitors the surrounding ambient light conditions to detect the transition from a light to a dark state is disclosed. Upon detection of the transition of the ambient light to a dark state, the electronic control system opens a gas flow control valve to allow the flow of gas from a gas supply line through a mixing chamber wherein the gas is mixed with air to form a combustible gas mixture that passes through a venturi tube and a burner head assembly, exiting the burner head assembly at mantels. A spark is generated to ignite the combustible gas mixture passing out of the mantels, and a sensor detects and verifies the ignition of the combustible gas mixture at the mantels so as to verify to the system that the lamp of the gas light assembly is lit during dark conditions and is unlit and the flow of gas shut off during light conditions.

Abstract: A direct spark ignition control system is provided for controlling for a gas fireplace burner. A solenoid is operatively controlled for supplying gas to the gas fireplace burner. A high voltage spark ignition circuit is operatively controlled for generating ignition sparks near the gas fireplace burner. A flame sensing circuit coupled to the gas fireplace burner provides a feedback signal to activate and deactivate the high voltage spark ignition circuit. A timing and control circuit provides a control signal to energize the solenoid and provides a control signal to deactivate the high voltage spark ignition circuit and a control signal to deenergize the solenoid after a set time period with the burner flame feedback signal activated.

Abstract: An apparatus 9 for diagnosing failures in the combustion system to be installed in the regenerator of an absorption chiller is adapted to automatically prepare quantitative diagnosis data from a plurality of items of measurement data. The apparatus comprises an abnormality degree calculating circuit 2 for calculating degrees of abnormality serving as indexes for discriminating failures, from different items of data obtained by a combustion system control unit 1, a binary conversion circuit 4 for converting the abnormality degrees obtained from the circuit 2 to binary data representing "normal" or "abnormal," a condition judging circuit 5 for discriminating types of states of failures from the binary data by driving a diagnosis knowledge base 7, and a diagnosis data calculating circuit 6 for calculating diagnosis data from the abnormality degrees and types of failure states by driving the base 7.

Abstract: A gas premix burner in which gas and air are mixed in a suction region of an impeller to form a combustion mixture. The impeller is associated with a blower housing and an electronic control circuit board, all of which are arranged upstream in a blower chamber having at least one flame separating wall. The arrangement prevents the gas and the combustion mixture from reaching the motor landings or the printed circuit board.

Abstract: An atmospheric burner is associated with a flame presence sensor and an electrical-discharge ignition device. It is fed via a flow rate control device. Both the ignition device and the flow rate control device are controlled by a microcontroller. A user interface enables the user to select the desired power by sending to the microcontroller a request for altering the flow rate and hence for altering the minimum power deliverable by the burner.

Abstract: A process for controlling a gas blower burner in which an ionization electrode sends an electrical variable derived from the combustion temperature or the lambda value to a control circuit, which compares this variable with a selected electrical set point and adjusts the gas-to-air ratio (lambda value) to a corresponding lambda set point. To compensate the effect of a condition-dependent change in the proportionality between the lambda value and the electrical measured variable derived from it on the control in such a way that the desired lambda set point will be maintained, a calibration cycle is run from time to time. The lambda value is reduced from a value of >1 during this cycle. The maximum obtained at lambda=1 is stored. The electrical set point is adjusted with this maximum.

Abstract: An electric control is shown adapted for use with gas furnaces which controls fan motors, ignition controls and a gas valve based on inputs from a room thermostat, limit switches, a flame probe, a flame roll-out probe, and a condensate sensor. A roll-out detection circuit utilizing flame rectification includes a multidirectional roll-out probe 16 coupled to a microcontroller (U2) through an inverter (U3) to provide both fault both protection and fault identification. A condensate sensor (20) in the form of a conductive condensate sensor member is also coupled to the microcontroller (U2) through an inverter (U3) to detect the presence of condensate build-up.

Abstract: A novel control system for altering a fixed pattern of gas flames in a fireplace having artificial logs comprises a log set having a burner system and the burner system having a gas valve control which is coupled to source of gas or air to be regulated. The control system has a valve which controls the air or gas being supplied to the burner and a control sensor is coupled to the control system for activating the time sequence of the cycle of the control system so as to raise or lower the gas flames being regulated and to disturb the pattern of gas flames to produce the effect of dancing flames.

Abstract: A method of displaying a possible remaining time of a combustion operation in a combustion appliance and an apparatus thereof are disclosed. The combustion appliance has a fuel tank for containing fuel, a burner for performing the combustion operation of the fuel supplied from the fuel tank, and an electromagnetic pump for supplying the fuel in the fuel tank to the burner. A microprocessor gauges a quantity of the fuel in the fuel tank, and calculates a total heat amount according to the quantity of the residual fuel. Also, the microprocessor calculates the heat supply amount per time on the basis of the driving frequency of the electromagnetic pump. The possible remaining time of the combustion operation is calculated by dividing the total heat amount by the heat supply amount per time. The microprocessor displays the possible remaining time of the combustion operation to the exterior of the combustion appliance through the display part.