The water heater may be configured to execute a normal operation in which a heating means is continuously operated in an ON state in a case where a required heat quantity is greater than or equal to a minimum heat quantity. The water heater may be configured to execute an intermittent operation in which the heating means is alternately and repeatedly operated in the ON state and an OFF state repeatedly in a case where the required heat quantity is less than the minimum heat quantity. The water heater may be configured to change a distribution ratio of a flow control mechanism in the normal operation and in the intermittent operation. An operating speed of the flow control mechanism in the intermittent operation may be faster than an operating speed of the flow control mechanism in the normal operation.

A water heater system includes a water heater rack system with a plurality of vertically stacked tankless water heaters and a water heater storage tank and provides the ability to install a water heater in environments where horizontally oriented heater rack systems would not fit. The tankless water heaters comprise a bifurcated vent arrangement with separate intake and exhaust vents. Accordingly, vent pipes of diameters of two (2) inches or less may be used in comparison to coaxial vent arrangements which may have diameters of three inches or more. The smaller vent pipe diameter allows a plurality of water heaters to be stacked, one above the other, such that the water heater rack system has a maximum height of 76 inches or less. This vertical orientation may allow tankless water heaters to be installed in an environment where a horizontally configured plurality of tankless water heaters would not fit.

Disclosed herein are connectors for a tankless water heater. The connectors can comprise a flange, an aperture extending through the flange having a first diameter, one or more slots extending through the flange, a connector portion substantially surrounding the aperture and extending outward from the flange away from the tankless water heater. The aperture can correspond to an air inlet extending into the tankless water heater, and the air inlet can have a second diameter that is larger than the aperture. To keep the flange in place, the one or more slots can correspond to one or more fastening holes in the tankless water heater. The one or more slots can be substantially parallel and on opposite sides of the aperture. The connector can be in a secured state when the one or more slots are fastened to the one or more fastening holes.

The present invention provides a combustion device. In ON-OFF combustion control processing for intermittently performing the combustion operation of burners (4), a control unit (30) of a combustion device (water heater) (1), which includes the burners (4), a fuel supply unit (5), and a combustion fan (10), controls the fuel supply unit (5) and the combustion fan (10) so as to change the amount of a fuel to be supplied to the burners (4) and the number of rotations of the combustion fan (10) according to a required amount of heat for the temperature control of a target fluid (water for hot water supply) when the burners (4) are ignited to restart a combustion operation after the burners (4) are extinguished.

[Problem] To provide a water heating apparatus which has a inverse combustion type burner installed within a case for a heat exchanger so as to cause heat to be transferred from an outer peripheral flange of the burner to the heat exchanger case. [Solution] This water heating apparatus is provided with: a fan for supplying combustion air; a chamber case which is connected to the fan and which has set therein a chamber where an air-fuel mixture is formed; a inverse combustion type burner for combusting the air-fuel mixture supplied from the chamber; a heat exchanger in which combustion gas generated by the burner is introduced into a case where water is heated; and sealing member which is installed between a peripheral flange of the chamber case and a peripheral flange of the case, wherein the burner is set inside the case, and an outer peripheral flange of the burner is anchored to an inner wall surface of the case.

A microwave heating apparatus is provided herein comprising a tubing conduit consisting of two or more removable bend portions connected to each other. The tubing conduit is supported by a support system. Each removable bend portion includes a microwave emitter to heat a fluid flowing through the conduit. The apparatus can replace or be integrated into existing heating equipment used in, for example, steam cracking of hydrocarbons. Also provided are pipe segments, such as spools, that are adapted for heating a fluid by applying microwave energy. The pipe segments can be lined with microwave absorbing materials and comprise an opening through which an insert comprising a microwave emitter can be removably inserted and retained.

Provided is a miniaturized water heater having a plate type heat exchanger. The water heater includes a combustion device generating combustion gas by burning fuel; a heat exchange device heating hot water by heat exchange with the combustion gas; and an exhaust part exhausting the combustion gas after heat exchange. The heat exchange device includes a plate laminate in which vertically standing plates are laminated with gaps, and the hot water is heated by alternately flowing the combustion gas and the hot water through the gaps of the plate laminate. The combustion gas flowing in a vertical direction from the combustion device is introduced vertically or substantially vertically into an introduction part provided on a combustion device side of the plate laminate, and a flow direction of the combustion gas in the plate laminate is reversed to discharge the combustion gas to the exhaust part.

A water heater includes a first heater, a second heater, and a controller. The controller can enable different operational modes of the water heater, wherein only the first heater operates, only the second heater operates, or both the first and the second heaters operate. The controller can also be configured to enable a hybrid operational mode and a bypass operational mode. Further, in the different operational modes, the controller can direct water flow to at least one of a first conduit coupled to the first heater, a second conduit coupled to the second heater, and a bypass conduit. The controller can be configured to receive input signals relating to environmental conditions around the water heater and/or an aquatic system in which the water heater is installed.

A hot water device includes a heat exchanger and an apparatus to which the heat exchanger is to be connected. First and second cases for the heat exchanger and the apparatus to which the heat exchanger is to be connected include first and second flange portions laid over each other and welded together. The first and second flange portions are each demarcated into a corner flange portion corresponding to one of first and second corner portions, and into a non-corner flange portion other than the corner flange portion. The non-corner flange portions protrude more to the outside of the first and second cases than the corner flange portions.

A water heater includes an outer casing defining a longitudinal axis, an axial direction being defined as extending along the longitudinal axis. The water heater further includes a combustor for production of hot flue gases, a primary heat exchanger including a tube positioned within the outer casing, and a secondary heat exchanger including a plurality of plates coupled together by brazing to form a brazed plate heat exchanger. The secondary heat exchanger includes a first set of passages defined between the plates, and a second set of passages defined between the plates and alternating with the first set of passages in the axial direction. The primary and secondary heat exchangers are in fluid communication such that the flue gases flow through the second set of passages before being exhausted, and water to be heated flows through the first set of passages to a delivery point for use upon demand.