In an indoor installation type combustion apparatus in which an upper surface of the exterior case has formed therein: a cylindrical exhaust connection port which is in communication with an exhaust duct and which is connectable to an exhaust pipe; a first cylindrical air supply connection port which is connectable to an air supply pipe of double-pipe system containing therein the exhaust pipe and which encloses the exhaust connection port; and a second cylindrical air supply connection port which is connectable to an air supply pipe of twin-pipe system which is separate from, and independent of, the exhaust pipe, a low-cost apparatus is provided in which the air flowing in from whichever the first and the second air supply connection ports will be treated by one and the same supply-air filter. An air supply box which is in communication with both the first and the second air supply connection ports is disposed. An outlet opening is formed at one place of the air supply box so that the air flowing in from an arbitrary air supply connection port between the first and the second air supply connection ports is discharged into an inner space of the exterior case. A supply-air filter to collect foreign matters in the air is mounted in the outlet opening.

A heat exchanger includes: a case which has a first side wall that stands upright in a vertical height direction and to which a heating medium is supplied inside; and heat transfer tubes for heating hot water housed in the case. Two end portions of the heat transfer tubes in a longitudinal direction are joined to the first side wall via brazing portions, and the heat transfer tubes are supported by the first side wall. The heat exchanger further includes heat transfer tube support portions provided on the first side wall for supporting portions of the heat transfer tubes near the first side wall to prevent the portions of the heat transfer tubes near the first side wall from descending below a first predetermined height.

A method of operating a gas heater for water including the steps of restricting a water flow to the gas heater; determining a first rate of a first gas heating for the restricted water flow; adjusting the gas heating to the restricted water flow; repeating the previous steps until a heated water has a temperature above a temperature threshold; removing the restriction to the water flow to increase the water flow; and determining a second rate of a second gas heating for the increased water flow.

An aspect of the present disclosure provides a flow channel cap plate that constitutes a combustion chamber assembly including a combustion chamber and a plurality of insulating pipelines disposed on left/right side surfaces of the combustion chamber, the flow channel cap plate forming an insulating flow channel by covering the front surface of the combustion chamber, the flow channel cap plate including an inlet part including an inlet, and an inlet flow channel cap covering the front surface of the combustion chamber, an inlet space part is formed by covering the front surface of the combustion chamber with the inlet flow channel cap, the inlet is an entrance of the insulating flow channel, the plurality of insulating pipelines include a plurality of inlet insulating pipelines, and the inlet space part is a space that communicates the inlet with the plurality of inlet insulating pipelines.

A water heater can include a baffle and a slab heat exchanger with at least two rows of heat exchanger tubes, each row comprising a plurality of heat exchanger tubes. At least one of the heat exchanger tubes comprises a tube and a plurality of fins on the exterior of the tube circumscribing the tube, wherein the outer edge of each fin of the plurality of fins is bent at least at the same three areas of each fin such that the bends form at least three flat or concave areas running along the length of the heat exchanger tube.

Embodiments include various water heaters. In one example, a water heater includes a burner, an exhaust vent, a corrugated baffle having a first slit having a first length and a second slit having a second length that is less than the first length, and a heat exchanger. The heat exchanger includes a first set of heat exchanger tubes arranged in a first row, and a second set of heat exchanger tubes arranged in a second row, the second set of heat exchanger tubes having a third tube having a first angled surface and a second angled surface, where the first angled surface and the second angled surface together form a fin. The third tube can be arranged such that the fin is disposed at least partially between the first curved outer surface and the second curved outer surface.

A gas manifold allows each distribution chamber to be fed with fuel gas at an appropriate flow rate irrespective of an increase in the number of distribution chambers included in the gas manifold. A gas manifold distributes fuel gas flowing in through an inlet to a plurality of distribution chambers through a main channel. The main channel includes a flow guide that guides the fuel gas toward a maximum distribution chamber and reduces the fuel gas flowing into other distribution chambers. This allows fuel gas at a sufficient flow rate to be fed more easily to the maximum distribution chamber than to the other distribution chambers for a larger number of distribution chambers included in the gas manifold, allowing the plurality of distribution chambers to be fed with fuel gas at appropriate flow rates.

The present invention provides a method of operating a gas heater for water including the steps of: restricting a water flow to the gas heater; determining a first rate of a first gas heating for the restricted water flow; adjusting the gas heating to the restricted water flow; repeating the previous steps until a heated water has a temperature above a temperature threshold; removing the restriction to the water flow to increase the water flow; and determining a second rate of a second gas heating for the increased water flow. The present invention also provides a gas water heater which utilises such a method.

In a water heater provided with an inlet pipe a downstream end of which is connected with an upstream end of a water heating channel of a heat exchanger for producing hot water, an outlet pipe an upstream end of which is connected with a downstream end of the water heating channel, and a bypass pipe branching at a part of the inlet pipe, which is positioned at an upstream-end part away from an upstream end, and is connected with a part of the outlet pipe, which is positioned at a more downstream part than at an upstream end, a connecting part of the bypass pipe with the outlet pipe and another connecting part of an inlet pipe and the upstream end of the water heating channel are arranged at a same height in a setting state of the water heater.

A gas heater for a swimming pool or spa includes a cabinet defining an interior, a combustion chamber enclosure, a heat exchanger positioned within the combustion chamber enclosure, a burner, a combustion blower configured to provide combustible gas to the burner, and electrical components positioned within the cabinet. The cabinet has a plurality of side panels and a top panel covering a top opening to the interior of the cabinet. The combustion chamber enclosure defines a combustion chamber, and is positioned within the interior of the cabinet. The combustion chamber enclosure also includes a burner opening in which the burner is positioned such that the burner is configured to dissipate combustible gas into the combustion chamber. At least one of the electrical components is configured to control the gas heater. The electrical components are accessible through the top opening when the top panel is removed.