Methods, systems, and circuitries are provided for detecting flame in a fuel oil burner. In one example, a method includes receiving a series of one or more light samples, each indicative of a level of light. When the fuel oil burner is operating in the flame expected mode, the method includes determining whether the values of the one or more of the light samples exceed a flame threshold; determining whether the values of the one or more of the light samples meet secondary criteria; determining that a flame is present when the values of the one or more light samples exceed the flame threshold and meet the secondary criteria; and determining that a flame is not present when the values of the one or more light samples are below the flame threshold or do not meet the secondary criteria.

Methods for regulating a heating device, which includes a combustion chamber, into which combustion air is introduced via a controllable blower. An operating variable and a speed of the blower are measured. An operating coefficient is determined on the basis of the measured operating variable and the measured speed. A volume flow coefficient is determined on the basis of reference values for the operating coefficient. A volume flow of the combustion air being determined on the basis of the volume flow coefficient. A calibration of the reference values is carried out for the operating coefficient.

A non-transitory computer readable medium with instructions stored thereon, the instructions executable by one or more processors for selecting infrequent or frequent autotuning of a combustor; and determining the health of a combustor. Also, a method of monitoring a combustor within a gas turbine engine system, comprising providing a gas turbine engine system, wherein the gas turbine engine includes an autotuning system; selecting infrequent or frequent autotuning of the combustor; and determining the health of the combustor; wherein said determining the health of a combustor comprises receiving real-time fuel gas temperature data from at least one thermocouple.

A non-transitory computer readable medium with instructions stored thereon, the instructions executable by one or more processors for selecting infrequent or frequent autotuning of a combustor; and determining the health of a combustor. Also, a method of monitoring a combustor within a gas turbine engine system, comprising providing a gas turbine engine system, wherein the gas turbine engine includes an autotuning system; selecting infrequent or frequent autotuning of the combustor; and determining the health of the combustor; wherein said determining the health of a combustor comprises receiving real-time fuel gas temperature data from at least one thermocouple.

A method of calibrating a furnace includes determining a first flame stabilization period for the furnace that avoids detachment of a flame from a burner within a burner box of the furnace, determining a second flame stabilization period that is longer than the first flame stabilization period and avoids emission of a combustion tone from the furnace, and configuring a controller of the same or another furnace to utilize a flame stabilization period that has a duration between the first and second flame stabilization periods. Each flame stabilization period commences upon ignition of a premixed mixture of air and fuel at the burner while an inducer fan operates within a first range of fan speeds, and terminates when the rotational speed of the inducer fan increases to a second range speeds that is greater than the entire first range.

In a gas hot water heater, changes of the signal output of an A/F sensor are calibrated in the atmosphere, in which the A/F sensor detects an oxygen concentration in a combustion tube. The gas supplied via a gas supply pipe is injected, together with in-taken air, into a combustion tube, which is incorporated in a hot water supply tank, via an injection unit. A proportional valve controls a combustion state in the combustion tube based on the detected oxygen concentration to thereby heat water supplied in the hot water supply tank. A purging process is performed to supply air into the combustion tube, at a timing between an extinguishment operation first performed after the ignition the gas mixture in the combustion tube and a re-ignition operation. Changes of signal output characteristics of the A/F sensor are subject to the calibration after the purging process.

Boiler systems and associated control systems, methods for operating same, are described herein. In one example embodiment, a boiler system includes a furnace, an exhaust passage, an air passage, a FGR passage, a flue gas valve that is adjustable by way of a first actuator, a NO.sub.X gas sensor, an oxygen gas sensor, and an additional valve that is adjustable by way of a second actuator. Further, the boiler system includes at least one processing device coupled to the NO.sub.X gas sensor, the oxygen gas sensor, the first actuator and the second actuator. The at least one processing device is configured to generate control signals that are provided to the first actuator and second actuator, and also configured to generate correction factors by way of a calibration process and to utilize one or more of the correction factors in determining one or more of the control signals.

Method for operating a gas burner appliance (10). During burner-on-phases a gas/air mixture having a defined mixing ratio of gas and air is provided to a burner chamber (11). Said gas/air mixture is provided by a mixing device (23) mixing an air flow with a gas flow. Said mixing device (23) has at least two Venturi nozzles being connected in parallel. Said air flow is provided by a fan (14) in such a way that the fan speed of the fan (14) depends on a desired burner load. The fan speed range of the fan (14) defines a modulation range of the gas burner appliance (10). Said defined mixing ratio of gas and air of the gas/air mixture is controlled over the modulation range of the gas burner appliance (10) by a gas regulating valve (18). Said gas regulating valve (18) has a pneumatic controller (24) controlling the mixing ratio of gas and air on basis of a pressure difference between the gas pressure of the gas flow in the gas pipe (16) and a reference pressure. During burner-on-phases the combustion quality is monitored on basis of a signal provided by a combustion quality sensor. The defined mixing ratio of gas and air of the gas/air mixture can be calibrated during on basis of the signal provided by the combustion quality sensor, namely by adjusting during calibration a position of a throttle (17). The calibration of the gas/air mixture is performed in such a way that for calibration at least one of the Venturi nozzles (28) of the mixing device (23) is closed while at least one of the Venturi nozzles (28) of the mixing device (23) is opened.

A method for determining an change in an operating condition of a gas burner appliance. In some instances, a calibration of a gas/air mixture may be performed when the combustion quality of the gas burner appliance diminishes. This may be accomplished by adjusting a throttle position of a throttle valve that throttles the gas to the gas burner appliance. After calibration has been performed, a throttle position of the throttle valve is determined, and based on the throttle position determined after calibration, a change of an operating condition of the gas burner appliance is detectable.

Method for operating a gas burner appliance (10) comprising: a combustion chamber (11), an ignition device (27), a fan (14), a gas safety valve unit (19) assigned to the gas duct (16), an electric gas flow modulator (18) assigned to the gas duct (16), a sensor (21) positioned between the gas safety valve unit (19) and the gas flow modulator (18), wherein the gas burner appliance (10) is operated to determine the gas family of the gas of the gas/air mixture by the following steps: Before the gas burner appliance becomes started measuring the ambient air pressure by the sensor (21), wherein the ambient air pressure is measured when the safety valve unit (19) is closed, the gas flow modulator (18) is opened and the fan (14) is stopped. When the gas burner appliance (10) becomes started running the fan (14) at a defined fan speed, increasing the opening of the gas flow modulator (18) while activating the ignition device (27) trying to ignite the gas/air mixture until the activation of ignition device results into a combustion of the gas/air mixture. Determining from the fan speed of the fan (14) and from the measured ambient air pressure an air volume flow. Measuring the gas pressure by the sensor (21) when the safety valve unit (19) is opened, the gas flow modulator (18) is opened and the fan (14) is running. Determining from the opening of the gas flow modulator (18) at which the combustion started and from the measured gas pressure a gas volume flow. Determining a ratio between the gas volume flow and the air volume and from said ratio the gas family of the combusted gas.