Abstract: A method of forming an assembly between a panel and a tube includes forming a hole in the panel, where a diameter of the hole is smaller than an outer diameter of the tube, and preforming a first end of the tube to conceal the hole of the panel. A diameter of the preformed portion is greater than the diameter of the hole and the outer diameter of the tube. The method further includes aligning a second end of the tube with the hole of the panel, followed by inserting the tube into the hole by application of axial force on the tube until the preformed first end of the tube abuts a periphery of the hole of the panel. The method also includes achieving an interference fit between the hole of the panel and the tube.

Abstract: A method of forming an assembly between a panel and a tube includes forming a hole in the panel, where a diameter of the hole is smaller than an outer diameter of the tube, and preforming a first end of the tube to conceal the hole of the panel. A diameter of the preformed portion is greater than the diameter of the hole and the outer diameter of the tube. The method further includes aligning a second end of the tube with the hole of the panel, followed by inserting the tube into the hole by application of axial force on the tube until the preformed first end of the tube abuts a periphery of the hole of the panel. The method also includes achieving an interference fit between the hole of the panel and the tube.

Abstract: A fuel-fired heating appliance has two fuel flow paths to a burner, each actuatable to a closed state and to an open state. A heat exchanger is in fluid communication with an area proximate the burner. A controller executes the steps: (a) while the first fuel flow path is closed, opening the second flow path; (b) following ignition of fuel flowing from the second flow path, opening the first fuel flow path; and (c) following step (b), closing the second fuel flow path while opening the first fuel flow path.

Abstract: A fuel-fired heating appliance has two fuel flow paths to a burner, each actuatable to a closed state and to an open state. A heat exchanger is in fluid communication with an area proximate the burner. A controller executes the steps: (a) while the first fuel flow path is closed, opening the second flow path; (b) following ignition of fuel flowing from the second flow path, opening the first fuel flow path; and (c) following step (b), closing the second fuel flow path while opening the first fuel flow path.

Abstract: A fuel-fired heating appliance comprises a burner and a first housing adjacent the burner so that an interior of the first housing receives combustion gasses from combustion at the burner. A heat exchanger defines a second housing with an inlet proximate an outlet of the first housing so that the inlet of the second housing receives combustion gasses from the outlet of the first housing, and wherein the first and second housings attach at an interface. A barrier extends within, and across an interface between, the outlet of the first housing and the inlet of the second housing and defines a thermal resistance that inhibits heat transfer from the combustion gasses to the interface.

Abstract: A fuel-fired heating appliance has two fuel flow paths to a burner, each actuatable to a closed state and to an open state. A heat exchanger is in fluid communication with an area proximate the burner. A controller executes the steps: (a) while the first fuel flow path is closed, opening the second flow path; (b) following ignition of fuel flowing from the second flow path, opening the first fuel flow path; and (c) following step (b), closing the second fuel flow path while opening the first fuel flow path.

Abstract: A fuel-fired heating appliance comprises a burner and a first housing adjacent the burner so that an interior of the first housing receives combustion gasses from combustion at the burner. A heat exchanger defines a second housing with an inlet proximate an outlet of the first housing so that the inlet of the second housing receives combustion gasses from the outlet of the first housing, and wherein the first and second housings attach at an interface. A barrier extends within, and across an interface between, the outlet of the first housing and the inlet of the second housing and defines a thermal resistance that inhibits heat transfer from the combustion gasses to the interface.

Abstract: A burner assembly for a fuel-fired heating appliance that defines a direction of flow of a fuel and air mixture in a flow path. The burner assembly comprises a plurality burners defined in a unitary mesh structure. Each burner defines at least one peak at a distal end thereof in a direction of flow of a fuel and air mixture. The burner assembly also comprises a diffuser plate having a plurality of perforated areas defined therein and one or more imperforate areas between respective perforated areas of the plurality of perforated areas. The perforated areas respectively correspond to the plurality of burners. The diffuser plate is disposed in a fixed position upstream of the mesh structure so that, when the burner assembly is disposed in the flow path, a respective flow of the fuel and air mixture is directed from each of the plurality of perforated areas to its corresponding burner of the plurality of burners.

Abstract: A burner assembly for a fuel-fired heating appliance that defines a direction of flow of a fuel and air mixture in a flow path. The burner assembly comprises a plurality burners defined in a unitary mesh structure. Each burner defines at least one peak at a distal end thereof in a direction of flow of a fuel and air mixture. The burner assembly also comprises a diffuser plate having a plurality of perforated areas defined therein and one or more imperforate areas between respective perforated areas of the plurality of perforated areas. The perforated areas respectively correspond to the plurality of burners. The diffuser plate is disposed in a fixed position upstream of the mesh structure so that, when the burner assembly is disposed in the flow path, a respective flow of the fuel and air mixture is directed from each of the plurality of perforated areas to its corresponding burner of the plurality of burners.

Abstract: Installed in a fuel-fired heating appliance is a specially designed burner assembly operative to receive and combust a pre-mixed flow of fuel and air to create therefrom a spaced apart plurality of flames which are aligned with and flow directly into the inlets of a corresponding spaced plurality of heat exchanger tubes. The flames create within the tubes hot combustion gases that transfer combustion heat to a supply fluid flowed externally across the tubes. The burners are of a hollow perforate metal construction, are mounted on and forwardly project from a support structure toward the tube inlets, and have rearwardly facing open inlet ends that receive the pre-mixed flow of fuel and air. In one illustrated embodiment thereof, the burners have conical configurations, and in another illustrated embodiment have generally dome-shaped configurations. Via a flame carryover structure, a single igniter is utilized to ignite all of the burners.