In a heating heat-source apparatus having input circuits configured to receive pieces of mutually independent heating demand information, an abnormality related to an operation for setting one input circuit among the input circuits to a use state is detected and reported. Input circuits receive heating demand information. An operation part receives an operation for setting one input circuit of the input circuits to a use state. A CPU receives heating demand information transmitted from the input circuit in the use state while receiving specified information for specifying the input circuit in the use state from the operation part. Each piece of heating demand information is voltage information having a predetermined voltage range. The CPU reports an abnormality related to an operation for setting when voltage information transmitted from the input circuit in the use state deviate from a voltage range specified in the specified information.

An extreme condensing boiler includes cold and hot water headers, burner, and multi-tubing heat exchanger, so that cold water absorbs heat from exhaust gas of the burner being heated to medium-hot, which absorbs heat generated by the burner being heated to hot water through absorbing heat from both sides of tube portion of the multi-tubing heat exchanger, and so that the hot water is delivered to the hot water header, and a combustion air heat exchanger is provided around the multi-tubing heat exchanger. The condensing boiler uses dual/triple tubes for fire and water tubes, increasing efficiency by absorbing heat from both sides. The fire tube is surrounded by the cold water tube so as to minimize exhaust gas temperature and maximize condensing by absorbing waste heat. The condensing boiler realizes a direct fire boiler through the fire and water tubes, and an energy-saving tankless boiler including headers and tubes only.

A heat exchanger includes a plurality of serpentine or U-shaped first heat transfer tubes disposed in a case and formed by connecting a plurality of straight tube body portions, which are arranged at intervals in an up-down height direction so as to extend in a horizontal direction, in series via a first connecting tube body portion, upper side and lower side header portions connected to respective end portions of the plurality of first heat transfer tubes, and a second heat transfer tube disposed in the case so that upper side and lower side end portions thereof are connected respectively to the upper side and lower side header portions and configured such that an intermediate region, which excludes at least the respective end portions and a region of an uppermost portion that is adjacent to the upper side end portion, is constituted by tube body portions that are tilted over the entire length thereof so as to gradually decrease in height from one end side toward another end side of the intermediate region. As a result, a malfunction in which a hot water supply operation becomes difficult due to freezing of the heat transfer tubes can be prevented appropriately.

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.

Provided is a condensate water trap for a gas furnace that collects and discharges condensate water produced in a heat exchanger and an exhaust pipe. The condensate water trap includes: a first inlet through which the condensate water produced in the heat exchanger is introduced; a second inlet through which the condensate water produced in the exhaust pipe is introduced; a first flow path through which the condensate water coming from the first inlet passes; a second flow path through which the condensate water coming from the second inlet passes; an outlet through which the condensate water introduced through the first and second inlets is discharged; a third flow path into which the residual condensate water passed through at least one of the first and second flow paths but not discharged through the outlet is introduced; and a sensing mechanism that senses if the amount of residual condensate water introduced into the third flow path is greater than or equal to a given amount.

Provided is a condensate water trap for a gas furnace that collects and discharges condensate water produced in a heat exchanger and an exhaust pipe. The condensate water trap includes: a first inlet through which the condensate water produced in the heat exchanger is introduced; a second inlet through which the condensate water produced in the exhaust pipe is introduced; a first flow path through which the condensate water coming from the first inlet passes; a second flow path through which the condensate water coming from the second inlet passes; an outlet through which the condensate water introduced through the first and second inlets is discharged; a third flow path into which the residual condensate water passed through at least one of the first and second flow paths but not discharged through the outlet is introduced; and a sensing mechanism that senses if the amount of residual condensate water introduced into the third flow path is greater than or equal to a given amount.

A plate heat exchanger includes a plurality of plates stacked so that a liquid flow passage is formed on the inside thereof, and a gas flow passage through which heating gas passes, the gas flow passage being formed between the plurality of plates and including a gas inflow opening portion and a gas outflow opening portion positioned on an opposite side to the gas inflow opening portion, wherein the gas outflow opening portion has a smaller opening area than the gas inflow opening portion. Thus, when the heating gas passes through the gas flow passage, even if the volumetric flow thereof decreases due to a reduction in temperature or condensation, a reduction in the flow velocity of the heating gas can be suppressed. Hence, a reduction in a heat transfer coefficient can be suppressed, leading to an improvement in heat transfer efficiency, and as a result, reductions in overall size, weight, and manufacturing cost can be achieved appropriately.

A heat exchanger includes a tube expansion portion provided on a heat transfer tube such that an outer peripheral surface of the heat transfer tube is pressed against an inner peripheral surface of a first hole provided in a side wall portion of a case, and a first concave surface portion that is provided in a part of an outer surface of the tube expansion portion and forms a first gap, into which brazing material of a first brazed portion advances, between the outer surface of the tube expansion portion and the inner peripheral surface of the first hole. Thus, the attachment strength of the heat transfer tube can be improved by means of a simple configuration.

A heat exchange cell is described comprising a containment casing comprising a rear wall, a front wall and a peripheral side wall, a helically-shaped heat exchanger comprising at least one tubular duct for the flow of a first heat transfer fluid coiled about a longitudinal axis of the helix according to a plurality of coils and mounted in the containment casing; a feeding zone of a second heat transfer fluid, intended for the heat exchange with the first heat transfer fluid, defined in the casing coaxially and internally with respect to the heat exchanger; a first chamber for collecting the second heat transfer fluid externally defined with respect to the heat exchanger between a radially outer wall thereof and the peripheral side wall of the containment casing; and a second chamber for collecting the second heat transfer fluid at least partially delimited by at least one separating element.

A heat exchange cell is described comprising a containment casing comprising a rear wall, a front wall and a peripheral side wall, a helically-shaped heat exchanger comprising at least one tubular duct for the flow of a first heat transfer fluid coiled about a longitudinal axis of the helix according to a plurality of coils and mounted in the containment casing; a feeding zone of a second heat transfer fluid, intended for the heat exchange with the first heat transfer fluid, defined in the casing coaxially and internally with respect to the heat exchanger; a first chamber for collecting the second heat transfer fluid externally defined with respect to the heat exchanger between a radially outer wall thereof and the peripheral side wall of the containment casing; and a second chamber for collecting the second heat transfer fluid at least partially delimited by at least one separating element.