A turn down ratio (TDR) damper which controls an amount of gas and air flowing in the TDR damper and deliver the controlled gas and air to a turbo fan is disclosed. The TDR damper includes: air passages comprising a first air passage and a second air passage, the first air passage and the second air passage separately formed so that the air move through each path; gas passages comprising a first gas passage and a second gas passage, the first gas passage and the second gas passage separately formed so that the gas move through each path; and opening and closing means for opening and closing the second air passage and the second gas passage at the same time. The air passages and the gas passages may be separately formed and reached outlets connected to the turbo fan so that the air and gas may be delivered to the turbo fan through a separate path.

A modulating burner apparatus includes a burner and a blower placed upstream of the burner. A venturi is placed upstream of the blower. A damper valve is placed upstream of the venturi. The damper valve has an open position and a restricted position. A smaller gas valve and a larger gas valve are communicated with the venturi. A controller is operably associated with the system to select a position of the damper valve and to select the appropriate one of the gas valves so as to provide a low output operation mode and a high output operation mode, which in combination provide an overall turndown ratio of at least 25:1.

A double flow rate gas solenoid valve has an inlet and at least a first outlet in a housing. First and second solenoids are selectively operable relative to first and second valve seats to establish first and second gas flow paths, respectively. The second flow path has a restriction thereby resulting in a lower gas flow rate through the second flow path than the first flow path. When connected to a common inlet of a burner, at least two, if not three flow rates can be provided by the valve.

A method for controlling a gas furnace including measuring an indoor temperature, comparing the indoor temperature with a set temperature for heating, and operating the gas furnace in weak heating with a predetermined heating capacity, which is lower than a maximum heating capacity of the gas furnace, when the set temperature for heating is higher than the indoor temperature by a temperature value, which is less than a predetermined temperature value. The predetermined heating capacity for weak heating is maintained at a current heating capacity for weak heating, when the gas furnace operates in weak heating, and when an operating duration with the current heating capacity for weak heating is less than a first time value.

A gas valve with two nozzles includes a valve body having an inlet, a primary outlet and a secondary outlet; a rotatable valve core is disposed inside the valve body; a valve rod inserted into the valve body; a first nozzle connected to a first outlet end of the primary outlet; and a second nozzle connected to a second outlet end of the secondary outlet; wherein, a connection chamber with a top opening for receiving the valve rod is mounted on the upper portion of the valve core; a ventilation chamber in communication with the primary outlet is defined in the lower portion of the valve core, the ventilation chamber having a side wall; a first high fire hole and a low fire hole both for communication between the inlet and the primary outlet are defined on the side wall of the ventilation chamber; and a second high fire hole for communication between the inlet and the primary outlet and a supplementary fire hole for communication between the ventilation chamber and the secondary outlet are defined on the side wall of the ventilation chamber of the valve core. In this gas valve, two nozzles can be kept in a gas injection state simultaneously only by rotating a valve rod to a certain position, without keeping a hand in a pressed-down operation position all the time.

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.

A fuel regulator, such for use in a commercial boiler, can include a control valve plumbed between a source line and a feed line. The feed line can be coupled to a burner configured to burn fuel supplied thereto at a range of pressures and the source line can be coupled to a source of fuel configured to supply the fuel at a pressure higher than the range of pressures. One or more sensors can be configured to detect an operating level of the burner. One or more actuators can be configured to control the valve according to the sensor and thereby control a flame from the burner.

Provided is a gas-air mixing device for a combustor which effectively controls the amount of gas and air supplied to a burner provided in a combustor, such as a boiler or a water heater, thus improving the turn-down ratio which leads to increased convenience for using hot water and heat and enhanced durability of the burner. The gas-air mixing device for a combustor comprises: a housing, connected on one side to a turbo fan; a discharge part disposed on one side of the housing and in contact with the turbo fan; first and second air supply parts, provided on the other side of the discharge part and separated by a first partition; first and second gas supply parts, separated by a second partition; and an opening/closing means for controlling the flow of gas and air by opening or blocking the second air supply part and the second gas supply part.

A control module for preventing acoustic resonance noise generation from a heat exchanger of a heating furnace, comprising a control signal generated by the control module. The control signal is configured to operate an induction fan of the heating furnace at more than one speed for a given heat demand mode of the heating furnace.

A gas-fired boiler comprises at least one burner (1) and feeding means (4) for feeding a fluid to such burner (1), said feeding means (4) being connected to a fan (5), a gas duct (7) being provided to feed gas to said fan (5). The burner comprises at least a first main flame-diffuser element (25) and a second auxiliary flame-diffuser element (26, the feeding means being a feeder duct (4) connected to the main diffuser element (25) and to the fan (5), said fluid comprising air or a mix of air and gas which is sent in such feeder duct (4), a tubular body (17) connected to the auxiliary diffuser element (26) opening in said duct (4), a gas carrying pipe (10) opening directly in such tubular body (17).