Abstract: An air blowing fan supplies an amount of air corresponding to a fan rotation speed to a burner during operation. A check valve has a biasing force that closes an exhaust vent, and is opened and closed in accordance with a relationship between a gas pressure in an exhaust passage and the biasing force. A controller performs a failure diagnosis for detecting an open failure of the check valve when a phenomenon in which the gas pressure is lower than a predetermined normal pressure range is detected in a case where the fan rotation speed is within a predetermined diagnosis rotation speed region. The diagnosis rotation speed region is set within a rotation speed range in which a degree of opening of the check valve changes with an increase in the fan rotation speed when the check valve is normally opened and closed.

Abstract: In an immediate hot water supply operation mode in which a circulation pump is activated while a hot water supply faucet is closed, a water heating apparatus forms an immediate hot water supply circulation path by an inner path including a water entry path, a heat exchanger, and a hot water output path and an outer path bypassing the hot water supply faucet, as being combined. A controller stores as an actual flow rate value for each immediate hot water supply operation mode, a flow rate detection value by a flow rate sensor at predetermined timing, and calculates a flow rate learning value based on a plurality of stored actual flow rate values. When the flow rate detection value becomes larger than a criterion value set in accordance with the flow rate learning value, use of the hot water supply faucet is detected and the circulation pump is deactivated.

Abstract: An exhaust adapter includes a cylindrical part for connecting an exhaust pipe of a combustion device to a collective exhaust duct; and a backflow prevention structure for preventing backflow of the exhaust from the collective exhaust duct side to the exhaust pipe side. The backflow prevention structure includes: a damper receiving part formed with an opening through which the exhaust from the exhaust pipe passes; an exhaust damper plate that opens the opening by pressure of the exhaust from the exhaust pipe and closes the opening by its own weight when there is no exhaust from the exhaust pipe; a support shaft that rotatably supports the exhaust damper plate; and a bearing part that supports the support shaft. A pair of shaft hole parts of the exhaust damper plate for inserting the support shaft is formed in a long hole shape.

Abstract: The disclosure provides a collective exhaust system capable of safely detecting a closing failure of a check valve of the collective exhaust system. The collective exhaust system includes: multiple combustion devices including blowing parts and exhaust pipes; a collective exhaust duct to which the exhaust pipes of the multiple combustion devices are respectively connected; and check valves respectively provided between the exhaust pipes and the collective exhaust duct. The collective exhaust system is configured to detect a closing failure of the check valves by performing, in a state where one of the blowing parts of the multiple combustion devices is stopped and all the other blowing parts are driven with a predetermined blower capacity, a backflow determination from the collective exhaust duct to the combustion device with the stopped blowing part, and by performing the backflow determination for the multiple combustion devices.

Abstract: As a circulation pump is activated while a hot water supply faucet is closed, an immediate hot water supply circulation path is formed to bypass the hot water supply faucet on the outside of a water heating apparatus and to pass through a heat exchanger in the inside of the water heating apparatus. A controller determines in a test mode, whether or not the immediate hot water supply circulation path has been formed by connection of a thermal water stop bypass valve, based on whether or not a temperature detector senses increase in temperature to a predetermined criterion temperature while the circulation pump and a heat source apparatus are active.

Abstract: A hot-water supply device includes a hot-water dispenser supplying hot-water, a hot-water supply path supplying the hot-water to a hot-water supply tap, a circulation path carrying out instant hot-water operation which circulates and heats the hot-water remaining in the hot-water supply path, a first clock repeatedly measuring unit times in which a pattern of hot-water usage of a user makes a round, and a flow rate sensor detecting the supply of the hot-water from the hot-water supply tap. The control portion detects, for each of the unit times and based on detection signals of the flow rate sensor, a time zone in which hot-water supply operation is carried out, and reserves, based on a time zone in a first unit time in which the hot-water supply operation is carried out, a time zone in a second unit time following the first unit time for carrying out the instant hot-water operation.

Abstract: A scale adhesion prevention operation of a circulation pump operated in an instant hot water operation is efficiently and appropriately performed. An instant hot water circulation path is formed to bypass a hot water tap outside a hot water supply device and to pass through a heat exchanger inside the hot water supply device by operating a circulation pump when the hot water tap is closed. A controller performs a protection operation which operates the circulation pump when a first condition in which stop of the circulation pump is continued for a first time is satisfied and a second condition related to stop of a hot water supply operation is further satisfied.

Abstract: A hot-water supply device includes a hot-water dispenser supplying hot-water, a hot-water supply path supplying the hot-water to a hot-water supply tap, a circulation path carrying out instant hot-water operation which circulates and heats the hot-water remaining in the hot-water supply path, a first clock repeatedly measuring unit times in which a pattern of hot-water usage of a user makes a round, and a flow rate sensor detecting the supply of the hot-water from the hot-water supply tap. The control portion detects, for each of the unit times and based on detection signals of the flow rate sensor, a time zone in which hot-water supply operation is carried out, and reserves, based on a time zone in a first unit time in which the hot-water supply operation is carried out, a time zone in a second unit time following the first unit time for carrying out the instant hot-water operation.

Abstract: An air blowing fan supplies an amount of air corresponding to a fan rotation speed to a burner during operation. A check valve has a biasing force that closes an exhaust vent, and is opened and closed in accordance with a relationship between a gas pressure in an exhaust passage and the biasing force. A controller performs a failure diagnosis for detecting an open failure of the check valve when a phenomenon in which the gas pressure is lower than a predetermined normal pressure range is detected in a case where the fan rotation speed is within a predetermined diagnosis rotation speed region. The diagnosis rotation speed region is set within a rotation speed range in which a degree of opening of the check valve changes with an increase in the fan rotation speed when the check valve is normally opened and closed.

Abstract: In an immediate hot water supply operation mode in which a circulation pump is activated while a hot water supply faucet is closed, a water heating apparatus forms an immediate hot water supply circulation path by an inner path and an outer path as being combined, the inner path including a heating mechanism including a combustion mechanism and a heat exchanger, the outer path bypassing the hot water supply faucet outside the water heating apparatus. The outer path includes a crossover valve. In the immediate hot water supply operation mode, a controller introduces intermittent combustion to control a detection temperature detected by the temperature sensor to a set temperature. In intermittent combustion, a minimum combustion state and a combustion stop state are alternately provided. In the minimum combustion state, a quantity of heat output from the combustion mechanism is reduced to a minimum value.

Abstract: In an immediate hot water supply operation mode in which a circulation pump is activated while a hot water supply faucet is closed, a water heating apparatus forms an immediate hot water supply circulation path by an inner path including a water entry path, a heat exchanger, and a hot water output path and an outer path bypassing the hot water supply faucet, as being combined. A controller stores as an actual flow rate value for each immediate hot water supply operation mode, a flow rate detection value by a flow rate sensor at predetermined timing, and calculates a flow rate learning value based on a plurality of stored actual flow rate values. When the flow rate detection value becomes larger than a criterion value set in accordance with the flow rate learning value, use of the hot water supply faucet is detected and the circulation pump is deactivated.

Abstract: A scale adhesion prevention operation of a circulation pump operated in an instant hot water operation is efficiently and appropriately performed. An instant hot water circulation path is formed to bypass a hot water tap outside a hot water supply device and to pass through a heat exchanger inside the hot water supply device by operating a circulation pump when the hot water tap is closed. A controller performs a protection operation which operates the circulation pump when a first condition in which stop of the circulation pump is continued for a first time is satisfied and a second condition related to stop of a hot water supply operation is further satisfied.

Abstract: As a circulation pump is activated while a hot water supply faucet is closed, an immediate hot water supply circulation path is formed to bypass the hot water supply faucet on the outside of a water heating apparatus and to pass through a heat exchanger in the inside of the water heating apparatus. A controller determines in a test mode, whether or not the immediate hot water supply circulation path has been formed by connection of a thermal water stop bypass valve, based on whether or not a temperature detector senses increase in temperature to a predetermined criterion temperature while the circulation pump and a heat source apparatus are active.

Abstract: A hot-water supply device includes a hot-water dispenser supplying hot-water, a hot-water supply path supplying the hot-water to a hot-water supply tap, a circulation path carrying out instant hot-water operation which circulates and heats the hot-water remaining in the hot-water supply path, a first clock repeatedly measuring unit times in which a pattern of hot-water usage of a user makes a round, and a flow rate sensor detecting the supply of the hot-water from the hot-water supply tap. The control portion detects, for each of the unit times and based on detection signals of the flow rate sensor, a time zone in which hot-water supply operation is carried out, and reserves, based on a time zone in a first unit time in which the hot-water supply operation is carried out, a time zone in a second unit time following the first unit time for carrying out the instant hot-water operation.

Abstract: A conduit made of a synthetic resin, having an inner surface and an outer surface, having concave portions and convex portions alternately and continuously provided in the length direction. The conduit is bendable. The conduit includes outer wall parts extending with a first width in the length direction; inner wall parts positioned radially inside relative to the outer wall parts and extending with a second width in the length direction; and side wall parts joining the outer wall parts and the inner wall parts so that the outer wall parts and the inner wall parts are alternately and continuously provided in the length direction. The outer surfaces of the outer wall parts each have, at both ends in the length direction, protruding parts, which protrude in the radial direction.

Abstract: An exhaust pipe holding member includes an annular portion, an annular outward protruding portion (protruding piece), and a flange portion. The annular portion is formed with a through hole penetrating from one end through the other end. The outward protruding portion protrudes peripherally outward from the outer peripheral surface of the annular portion. The flange portion is disposed closer to one end than to the outward protruding portion, extending peripherally outward from the outer peripheral surface of the annular portion, and is configured to have a thickness greater than that of the outward protruding portion. The flange portion is formed with an annular groove surrounding the through hole.

Abstract: An exhaust connection structure is constructed to connect a combustion apparatus and an exhaust tube having projections and recesses in an outer surface. The exhaust connection structure has a sealing member arranged on an outer circumferential surface of the exhaust tube and an exhaust joint arranged to sandwich the sealing member between the exhaust joint and the outer circumferential surface of the exhaust tube. The exhaust joint includes an engagement member and the engagement member has an annular portion and an engaging portion bent toward an inner circumference of the annular portion. The engaging portion is engaged with the projections and recesses in the exhaust tube.

Abstract: An exhaust tube holding member is supported by an exhaust pipe and holds, on an inner peripheral surface thereof, an exhaust tube to be inserted into the exhaust pipe. The exhaust tube holding member includes a first annular portion, a second annular portion, and an outward protruding portion. The first annular portion is formed with a first through hole. The second annular portion is formed with a second through hole in communication with the first through hole and having an inner diameter larger than that of the first through hole, and is connected to the first annular portion. The outward protruding portion protrudes peripherally outward from an outer peripheral surface of the second annular portion and is supported by the exhaust pipe. The inward protruding portion protrudes peripherally inward from an inner peripheral surface of the second annular portion and is supported by the exhaust pipe.