Abstract: A method of assembling multiple low NOx burners including the step of assembling multiple bodies, each body including a multiple first burner ports connected to a first burner inlet and multiple second burner ports connected to a second burner inlet. The method also including the step of selecting one of the bodies and inserting a first inlet tube into the second burner inlet to provide a fuel/air mixture to the second burner ports at a first rate. The method also including the step of selecting one of the bodies and inserting a second inlet tube into the second burner inlet to provide the fuel/air mixture to the second burner ports at a second rate different than the first rate.

Abstract: A gas water heater includes a water tank, a combustion chamber, a burner, a heat exchanger tube at least partially within the water tank, and a fan. The burner receives fuel gas and primary air from a first air-supply channel to create a primary air-fuel mixture for combustion in the combustion chamber with secondary air. The primary air-fuel mixture has a gas concentration above the upper explosive limit of the fuel gas. Secondary air is supplied through a second air-supply channel to the combustion chamber. The secondary air creates a low excess air ratio (e.g., below 1.5) for combustion in the combustion chamber. A totally sealed channel is defined from the air inlet of the fan to the heat exchanger tube.

Abstract: A method of assembling multiple low NOx burners including the step of assembling multiple bodies, each body including a multiple first burner ports connected to a first burner inlet and multiple second burner ports connected to a second burner inlet. The method also including the step of selecting one of the bodies and inserting a first inlet tube into the second burner inlet to provide a fuel/air mixture to the second burner ports at a first rate. The method also including the step of selecting one of the bodies and inserting a second inlet tube into the second burner inlet to provide the fuel/air mixture to the second burner ports at a second rate different than the first rate.

Abstract: A method of assembling multiple low NOx burners (100), a low NOx burners (100) and a tankless gas-fired water heater (500) are disclosed. The method includes the step of assembling multiple bodies (152), each body (152) includes multiple first burner ports (135) connected to a first burner inlet (125) and multiple second burner ports (150) connected to a second burner inlet (140). The method also includes the step of selecting one of the bodies (152) and inserting a first inlet tube (120, 220, 320, 420) into the second burner inlet (140) to provide a fuel/air mixture to the second burner ports (150) at a first rate. The method also includes the step of selecting one of the bodies (152) and inserting a second inlet tube (120, 220, 320, 420) into the second burner inlet (140) to provide the fuel/air mixture to the second burner ports (150) at a second rate different from the first rate.

Abstract: A method of assembling multiple low NOx burners (100), a low NOx burners (100) and a tankless gas-fired water heater (500) are disclosed. The method includes the step of assembling multiple bodies (152), each body (152) includes multiple first burner ports (135) connected to a first burner inlet (125) and multiple second burner ports (150) connected to a second burner inlet (140). The method also includes the step of selecting one of the bodies (152) and inserting a first inlet tube (120, 220, 320, 420) into the second burner inlet (140) to provide a fuel/air mixture to the second burner ports (150) at a first rate. The method also includes the step of selecting one of the bodies (152) and inserting a second inlet tube (120, 220, 320, 420) into the second burner inlet (140) to provide the fuel/air mixture to the second burner ports (150) at a second rate different from the first rate.

Abstract: A gas water heater includes a water tank, a combustion chamber, a burner, a heat exchanger tube at least partially within the water tank, and a fan. The burner receives fuel gas and primary air to create a primary air-fuel mixture for combustion in the combustion chamber with secondary air. The primary air-fuel mixture has a gas concentration above the upper explosive limit of the fuel gas. Secondary air is supplied to the combustion chamber through a secondary air conduit that is separate from the burner. The heat exchanger tube receives the products of combustion, transfers heat from the products of combustion to water in the tank, and exhausts of the products of combustion. Only air flows through the fan; no fuel-air mixture flows through the fan. The water heater utilizes partial premix combustion with low excess air ratio and low contaminant emission.