A method for operating a combustion chamber is provided. The method includes introducing a fuel into the combustion chamber via a plurality of nozzles, each nozzle having an associated stoichiometry for an output end of the nozzle. The method further includes measuring the stoichiometry of each nozzle via one or more sensors to obtain stoichiometric data, and determining that at least one of a frequency and an amplitude of spectral line fluctuations derived from the stoichiometric data has exceeded a threshold. The method further includes adjusting the stoichiometry of at least one of the nozzles based at least in part on the stoichiometric data so as to maintain a flame stability of the combustion chamber.

One or more techniques and/or systems are disclosed for a vent-free heater that may be installed in an area used for human occupancy, to provide heat to that area. Such a heater can comprise an environmental detector that senses ambient air conditions, and may provide data used to shut down the heater in predetermined threshold condition. In one implementation, a vent-free heater for installation in high altitudes can comprise a combustion region and a fuel supply component. The heater can comprise an environmental detector with a flameless sensor configured to detect an ambient level of a constituent of the atmosphere and generate a signal indicative of the constituent level; and a sensor interface that can control flow of fuel from the fuel supply, based at least upon a signal received from the sensor.

A water heater includes a water tank having an inlet and an outlet, and a flue extending through the tank. A nozzle is positioned near a first end of the flue, arranged so as to emit a fuel stream into the flue, and a flame holder is located within the flue in a position to receive the fuel stream and to hold a flame entirely within the flue. A controller variably controls a flow of fuel to the nozzle according to a temperature of water in the tank.

A system and method for heating process air is disclosed. Low NOx burners are provided with low temperature combustion air, e.g., less than about 0° C., and fuel at varying amounts to maintain a desired balance between low NO.sub.2 and low CO emissions. The amount of combustion air and the amount of fuel may be adjusted to achieve desired low NO.sub.2 and low CO via a feedback control system.

A flue gas analyser for determining the efficiency of a burner burning a supply gas and producing a flue gas by: calculating an efficiency of the burner based on a detected amount of a first target gas in the flue gas and an expected amount of the first target gas in the flue gas; predicting an amount of a second target gas in the flue gas based on the efficiency of the burner; estimating a composition of the supply gas based on a detected amount of the second target gas in the flue gas and the predicted amount of the second target gas in the flue gas; and correcting the calculated efficiency of the burner based on the estimated composition of the supply gas.

Briefly, apparatus and methods for detecting and terminating production of undesirable gases, such as carbon monoxide (“CO”), at a potential source, such as a household appliance. The apparatus and methods may determine a threshold level of the gas. In one embodiment, the method and apparatus may determine whether to provide power to a power supply input of a controller of a potential gas producing device based on the detected level of gas, where providing power to the power supply input of the controller of the potential gas producing device enables the controller of the potential gas producing device to provide power to the potential gas producing device. In another embodiment, when gas concentrations about a potential source are above a maximum threshold, the system communicates with a fuel supply valve of the potential source to cause the valve thereof to interrupt the supply of fuel to the potential source.

The present disclosure deals with the detection of a blockage in the air-supply duct or flue of a burner assembly. In some embodiments, a method or system may detect blockages in the form of coverings and with burner assemblies to burn fossil fuels. For example, a control device may generate: a first air-control signal; a fuel-control signal by adjusting the actual values of the ionization current to the ionization-current setpoint; a setpoint increased by a specified amount from the ionization-current setpoint; and a changed fuel-control signal by adjusting the actual values of the ionization current to the increased setpoint in the case of a first air-control signal. The control device may evaluate the changed fuel-control signal generated based on the increased setpoint by comparing it with a specified maximum value and based on the evaluation, to detect a blockage. The control device may recognize the blockage based on the evaluation if the fuel-control signal generated using the increased setpoint exceeds the specified maximum value.

Briefly, apparatus and methods for detecting and terminating production of undesirable gases, such as carbon monoxide (“CO”), at a potential source, such as a household appliance. The apparatus and methods may determine a threshold level of the gas. In one embodiment, the method and apparatus may determine whether to provide power to a power supply input of a controller of a potential gas producing device based on the detected level of gas, where providing power to the power supply input of the controller of the potential gas producing device enables the controller of the potential gas producing device to provide power to the potential gas producing device. In another embodiment, when gas concentrations about a potential source are above a maximum threshold, the system communicates with a fuel supply valve of the potential source to cause the valve thereof to interrupt the supply of fuel to the potential source.

Systems and methods operate to infer a fuel composition in a combustion system. The fuel composition may be inferred by receiving measured operating parameters including one or more of fuel data defining fuel characteristics used in combustion within a heater of the combustion system, emissions data defining emission gasses exiting the heater, airflow data defining ambient air being supplied to the heater and airflow rate of the air within the heater. One or more relationships within the measured operating parameters may be identified that result in a list of potential fuel compositions. One of the potential fuel compositions from the list may be selected having sufficient likelihood of resulting in the measured operating parameters as an inferred fuel composition. The output the inferred fuel composition to a heater controller of the combustion system and used for automatic control thereof.

A burner appliance is disclosed. The burner appliance includes a byproduct sensor in an exhaust flue and/or a barometric pressure sensor to detect an environmental pressure at the burner appliance. By calculating concentrations of combustion byproducts in the exhaust with the byproduct sensor, a controller can adjust blower speed and/or fuel rate to modify combustion efficiency. By calculating the environmental pressure at the burner with the barometric pressure sensor, the controller can adjust blower speed and/or fuel rate to modify combustion efficiency. The barometric-pressure data can also be used to adjust blower speed control bands, thereby calibrating the control bands based on environmental pressure. The environmental pressure can be indicative of altitude and/or weather conditions. Methods of operating said burner appliance are also disclosed.