An economizer having a structure capable of efficiently warming water and facilitating inspection and cleaning is obtained.

In an economizer for warming water by combustion exhaust gas generated by a boiler, to a cylindrical water pipe in which an inflow port and an outflow port are formed on a side surface and through which the water passes, a plurality of gas pipes erected for circulating the combustion exhaust gas are arranged in corresponding fan-shaped portions of the water pipe. The combustion exhaust gas introduced from a bottom surface side of the water pipe folds back at an upper part of the water pipe and flows downward, then folds back at a lower part of the water pipe, flows upward, and flows out from an upper surface side of the water pipe, whereby the plurality of gas pipes efficiently warms the water in the water pipe.

An economizer having a structure capable of efficiently warming water and facilitating inspection and cleaning is obtained. In an economizer for warming water by combustion exhaust gas generated by a boiler, to a cylindrical water pipe in which an inflow port and an outflow port are formed on a side surface and through which the water passes, a plurality of gas pipes erected for circulating the combustion exhaust gas are arranged in corresponding fan-shaped portions of the water pipe. The combustion exhaust gas introduced from a bottom surface side of the water pipe folds back at an upper part of the water pipe and flows downward, then folds back at a lower part of the water pipe, flows upward, and flows out from an upper surface side of the water pipe, whereby the plurality of gas pipes efficiently warms the water in the water pipe.

Water heaters, baffles for water heaters, and methods for manufacturing such baffles are disclosed, One baffle includes a core, an outer wall, and a plurality of fins. The outer wall surrounds the core and defines at least one flow path between the outer wall and the core. The plurality of fins extend from the outer wall toward the core. Each of the plurality of fins has a serpentine shape. One method for manufacturing a baffle includes extruding at least one portion of the baffle in one piece, the at least one portion of the baffle having an at least partially cylindrical outer wall u and a plurality of fins extending inward from the outer wall, each of the plurality of fins having a serpentine shape. One water heating system includes a burner, a vent, at least one flue tube, and at least one baffle as described above.

Water heaters, baffles for water heaters, and methods for manufacturing such baffles are disclosed, One baffle includes a core, an outer wall, and a plurality of fins. The outer wall surrounds the core and defines at least one flow path between the outer wall and the core. The plurality of fins extend from the outer wall toward the core. Each of the plurality of fins has a serpentine shape. One method for manufacturing a baffle includes extruding at least one portion of the baffle in one piece, the at least one portion of the baffle having an at least partially cylindrical outer wall u and a plurality of fins extending inward from the outer wall, each of the plurality of fins having a serpentine shape. One water heating system includes a burner, a vent, at least one flue tube, and at least one baffle as described above.