Frustoconical combustion chamber for a fluid heating device and methods for making the same

A method for manufacturing a fluid heating device, the method comprising:

• providing an outer shell including a fluid inlet and a fluid outlet;
• positioning a heat exchanger concentrically within the outer shell such that a channel is formed between an inner surface of the outer shell and an outer surface of the heat exchanger, the channel having a width in a range from approximately 0.25 inches to approximately 1.5 inches, the heat exchanger including an inlet tube sheet disposed proximate a first end of the heat exchanger, an outlet tube sheet disposed proximate a second end of the heat exchanger, and a plurality of heating tubes extending between the inlet tube sheet and the outlet tube sheet;
• providing a combustion chamber having a first end that has a first surface area and second end that has a second surface area larger than the first surface area;
• attaching the combustion chamber to the heat exchanger such that the combustion chamber is in fluid communication with the plurality of heating tubes;
• and
• connecting a blower system to the first end of the combustion chamber, the blower system being configured to provide an air/fuel mixture to the combustion chamber.