Abstract: A water heater apparatus includes a water conduit having an inlet and an outlet. A primary heat exchanger has a water side defining a portion of the water conduit. A burner is operatively associated with the primary heat exchanger for heating water in the water side of the primary heat exchanger. A variable flow blower provides pre-mixed combustion air and fuel gas to the burner at a controlled blower flow rate within a blower flow rate range. This apparatus allows the heat output of the water heater to be continuously varied within a substantial flow rate range having a turn down ratio of as much as four to one.

Abstract: A burner apparatus includes a mounting head having a fuel inlet opening defined in the mounting head for receiving combustion air and fuel gas through the opening. An inner support structure is attached to the mounting head. The inner support structure defines an interior zone communicated with the fuel inlet opening of the head. An exterior layer of flexible woven heat resistant material is received about the inner support structure and defines an exterior flame attachment surface. The mounting head may include a radial opening defined therethrough. An igniter is located outside of the mounting head adjacent the radial opening so that the igniter is proximally spaced from a combustion zone surround the burner apparatus. The burner apparatus may include a plurality of foraminous back pressure plates located in the interior zone distal of the igniter for balancing the pressure of the fuel gas/combustion air mixture along the length of the burner.

Abstract: A water heater apparatus includes a water conduit having an inlet and an outlet. A primary heat exchanger has a water side defining a portion of the water conduit. A burner is operatively associated with the primary heat exchanger for heating water in the water side of the primary heat exchanger. A variable flow blower provides pre-mixed combustion air and fuel gas to the burner at a controlled blower flow rate within a blower flow rate range. This apparatus allows the heat output of the water heater to be continuously varied within a substantial flow rate range having a turn down ratio of as much as four to one.

Abstract: A burner apparatus includes a mounting head having a fuel inlet opening defined in the mounting head for receiving combustion air and fuel gas through the opening. An inner support structure is attached to the mounting head. The inner support structure defines an interior zone communicated with the fuel inlet opening of the head. An exterior layer of flexible woven heat resistant material is received about the inner support structure and defines an exterior flame attachment surface. The mounting head may include a radial opening defined therethrough. An igniter is located outside of the mounting head adjacent the radial opening so that the igniter is proximally spaced from a combustion zone surround the burner apparatus. The burner apparatus may include a plurality of foraminous back pressure plates located in the interior zone distal of the igniter for balancing the pressure of the fuel gas/combustion air mixture along the length of the burner.