A controller monitors oxygen levels in a bio-fuel fired device and automatically controls dampers, blowers and the like to reduce generation of smoke or other pollutants, thereby promoting proper operation of a catalytic converter.

A heating apparatus can have a sealed combustion chamber, a burner, and various air channels to direct air into the sealed combustion chamber and to provide heated air to the desired area or environment such as an interior room. A channel can direct a flow of air along a face of the sealed combustion chamber to cool the face. The channel can be within or outside of the sealed combustion chamber. Alternatively, or in addition, the heating apparatus can be capable of operating as a direct vent device or as a vent free device.

A modulating gas valve assembly includes a modulating gas valve to variably control a flow of gas through the gas valve assembly and a control circuit. The control circuit includes a valve memory storing a calibration table for the modulating gas valve, and a controller communicatively coupled to the peripheral component. The calibration table includes a plurality of control settings for the modulating gas valve, each control setting being associated with a different gas flow rate. The controller is programmed to receive a command to open the gas valve, and to control the gas valve to a target control setting in the calibration table adjusted in accordance with a valve offset.

Disclosed herein is a method of controlling the air to fuel ratio in a burner containing a venturi assembly. The venturi includes an air inlet, a primary fuel inlet with a converging section, a throat portion downstream from the converging section, a diverging section downstream from the throat portion, an outlet, and a secondary gas inlet disposed downstream from the converging section and upstream from the outlet. The method comprises introducing fuel into the fuel inlet, receiving air through the air inlet by inspiration, and feeding a gas through the secondary gas inlet, the flow rate and content of the gas fed through the secondary gas inlet being selected to result in a desired air to fuel ratio through the outlet. A method of firing a heater, a burner, a furnace and firing control systems also are disclosed.

A high efficiency laminar flow burner system for proving a stream of heat energy including a supply input module for providing fuel and laminar streams of air to a combustion manifold. The laminar air delivery system includes a damper, a blower, and an air delivery controller. The air delivery controller receives an efficiency signal to control the flow of a laminar air intake stream by adjusting the damper. The combustion manifold includes an air-fuel mixing system, a stoichiometric unit, and a refractory unit each coupled to one another. The laminar air intake stream traveling from the supply input module passes through a stoichiometric unit body to meet with a first combustion stream from an air-fuel mixing chamber within the stoichiometric unit body to define a second combustion stream. The second combustion stream then travels across the refractory passageway to define a third combustion stream.

A modulating burner apparatus includes a variable speed blower feeding a multi-chamber burner having first and second burner chambers. A manifold system communicates the blower with the burner, and a flow control valve member is located between the blower and the second chamber of the burner. The flow control valve is configured to provide fuel and air mixture from the blower to only the first burner chamber at lower blower speeds of the blower and to both the first and second burner chambers at higher blower speeds of the blower.

A high efficiency laminar flow burner system for proving a stream of heat energy including a supply input module for providing fuel and laminar streams of air to a combustion manifold. The combustion manifold includes an air-fuel mixing system, a stoichiometric unit, and a refractory unit each coupled to one another. A first combustion stream is established at the air-fuel mixing chamber system as fuel exits an injector device at direction perpendicular to the laminar air intake stream. A laminar air intake stream traveling from the supply input module and along the staging passageway passes through a stoichiometric unit body at a plurality of air intakes to meet with the first combustion stream within to define a second combustion stream for introduction from the stoichiometric unit to the refractory unit. The refractory unit thus defines a third combustion stream as the second combustion stream travels across a refractory passageway.

Various embodiments of the teachings herein include a mixer disposed in a fuel gas combustion system and mixing air and fuel gas to form flammable mixed gases. The mixer may include: a Venturi tube having an air inlet, a fuel gas inlet, a gas mixture outlet, a central axis direction, and a throat positioned between the air inlet and the gas mixture outlet in the central axis direction, wherein the fuel gas inlet is disposed at the throat; and an adjustment component disposed in the Venturi tube downstream of the throat, the adjustment component drivable to move towards or away from the throat in the central axis direction, thereby changing a flow area of gas in the Venturi tube. The adjustment component comprises a conical valve plug with a conical outer surface thereof at a side facing towards the throat and fitting an inner surface of the Venturi tube.

A gas-powered heating system includes a burner, a modulating gas valve connected between a gas source and the burner to variably control a flow of gas from the gas source to the burner, and a peripheral component including a control circuit having a memory storing a calibration table for the modulating gas valve, and a processor. The calibration table includes a plurality of control settings for the modulating gas valve, each control setting being associated with a different gas flow rate. The control circuit is programmed by instructions stored in the memory and executable by the processor to receive a valve offset, determine to open the modulating gas valve, and control the gas valve to a target control setting in the calibration table adjusted in accordance with the valve offset.

An air fired burner may be operated by controlling a composition of the burner air flow that is provided to a burner air intake of the burner, including initially having at least a majority proportion of atmospheric air, and over time, reducing the proportion of atmospheric air in the burner air flow and increasing a proportion of a synthetic air that is derived at least in part from the exhaust gas flow produced by the burner, until the proportion of atmospheric air in the burner air flow is reduced to a minimal proportion, wherein as the proportion of atmospheric air is reduced and the proportion of the synthetic air is increased, a carbon dioxide concentration of the exhaust gas flow increases.