The present description discloses a combustion type water heater that heats water by burning fuel. The combustion type water heater includes: a burner that generates combustion gas by burning the fuel; a heat exchanger that exchanges heat between the water passing through on an inside of the heat exchanger and the combustion gas flowing on an outside of the heat exchanger, an exhaust pipe that discharges the combustion gas after the heat exchange in the heat exchanger as exhaust gas; an exhaust gas temperature detector that detects a temperature of the exhaust gas flowing in the exhaust pipe as an exhaust gas temperature; a clog degree detector that detects a degree of clog in the exhaust pipe; and a scale buildup determiner that determines whether or not scale has built up inside the heat exchanger based on the exhaust gas temperature and the degree of clog in the exhaust pipe.

Provided is a hot water supply apparatus. Processing executed by the hot water supply apparatus includes the following. A hot water supply set temperature is read from a memory. A maximum temperature of a housing is set by combustion level (combustion stage number) in accordance with a setting pattern predetermined according to the hot water supply set temperature. When it is intended to detect an end of operation of the hot water supply apparatus in the case of detecting no change in the hot water supply set temperature, a combustion operation is continued. The maximum temperature of the housing is set again by combustion level (combustion stage number) in the case of detecting a change in the hot water supply set temperature.

The present invention provides a hot water supply device. When a hot water supply operation is started in response to an instruction for checking a heat exchange state, a heat exchange state determiner 12 measures a post-boiling temperature Tup, which indicates the rise width of a temperature detected by a heat exchange outlet temperature sensor 26 from the point when the hot water supply operation stopped, and outputs a heat exchange success report if the post-boiling temperature Tup is lower than a first threshold temperature. Further, when the hot water supply operation is started independently of the instruction for checking a heat exchange state, the heat exchange state determiner 12 outputs a report of clogging of a heat exchanger if the post-boiling temperature Tup is higher than a second threshold temperature Bth, which is higher than the first threshold temperature Ath.

A door with a gas burner on an inner surface and a system for carrying a combustible gas to the burner on the outer surface thereof. The door comprises a pair of metal sheets rigidly connected to one another at the edges thereof, each sheet having input and output openings for the gas mixture that are mutually separated in order to leave an inner space receiving a deflector plate serving as a thermal shield to be swept over on either side by the flow of the gas mixture supplying the burner. This arrangement reduces heat loss through the door; thus, keeping the outer surface cold, avoiding the risk of burns, and preheating the gas mixture. The invention can be used in heating appliances.

The disclosed technology includes a water heater system having a blower, an igniter, a burner, a heat exchanger, and a refractory configured to attach to the burner and the heat exchanger. The refractory can include a unitary ceramic housing having a top and a plurality of sidewalls and be configured to retain heat from combustion gases. The top can have a burner aperture configured to receive at least a portion of the burner and the plurality of sidewalls can form a cavity configured to receive at least a portion of the heat exchanger. One or more of the sidewalls can additionally have a protrusion extending laterally along an inside surface of the sidewall that is configured to contact the heat exchanger to form a seal between the heat exchanger and the refractory. A sealing material can substantially create a seal between the refractory and the heat exchanger.

A hot water supply device including an inlet pipe, an outlet pipe, a burner unit, a heat exchanger, an exhaust aperture, a first temperature sensor detecting a measured exhaust temperature of the exhaust gas, a second temperature sensor detecting a water temperature of water entering the inlet pipe, and a processor. The processor is configured to obtain an error between the measured exhaust temperature and an estimated exhaust temperature, and detects that scale clogging has occurred inside the heat exchange tubing based on an index which is generated using the error between the measured exhaust temperature and the estimated exhaust temperature. The estimated exhaust temperature is a first predetermined value that is determined using a numerical equation which has at least the water temperature of water entering the inlet pipe and a scale number of the hot water supply device as variables of the numerical equation.

A combustion device including a chamber, a burner, a fan case, and a fan is provided. The chamber has a top wall. On the top wall, an inflow port penetrating through the top wall along a first direction and in communication with an internal space of the chamber is formed. The burner is attached to the chamber, so as to be spaced apart from and face the top wall in the first direction. In the fan case, a discharge port and an intake port penetrating through the fan case along the first direction and in communication with an internal space of the fan case are formed. The discharge port is connected with the inflow port. The fan is provided in the internal space of the fan case. A rotation axis of the fan is along the first direction.

A hot water appliance includes a housing defining an inner space; a heat source arranged in the inner space of the housing and comprising at least one burner; a flue gas discharge arranged in the inner space of the housing and configured to discharge combustion gases of the at least one burner therethrough; and a heat exchanger arranged in the inner space of the housing and associated with the flue gas discharge. The combustion gases of the at least one burner form a first heat exchanging fluid of the heat exchanger associated with the flue gas discharge. A flue gas discharge for a hot water appliance and a method for heating a fluid are also described.

A heat exchanger includes a tube expansion portion formed by expanding a heat transfer tube so that an outer peripheral surface of the heat transfer tube is pressed against an inner peripheral surface of a hole provided in a side wall portion of a case. The tube expansion portion includes first and second bulge portions positioned respectively on the inside and the outside of the side wall portion so as to sandwich the side wall portion in an axial length direction of the heat transfer tube and configured such that respective outer peripheral surfaces thereof partially bulge outward in a radial direction of the heat transfer tube, an end portion tip end of the heat transfer tube is positioned apart from the second bulge portion, and the end portion tip end and a part in the vicinity thereof are expanded so as to be included in a part of the tube expansion portion. Thus, effects such as improving the precision with which the side wall portion of the case, the heat transfer tube, and a connecting tube are fitted to each other can be achieved, and as a result, the respective parts can be brazed easily and appropriately.

A heat exchanger having a first heat exchanger tube and a second heat exchanger tube is disclosed. The first heat exchanger tube can have a first leg, a second leg, and a bend section, and the bend section of the first heat exchanger tube can include three or more bends, each of the three or more bends having a corresponding bend angle that is less than or equal to approximately 90 degrees. The second heat exchanger tube can have a first leg, a second leg, and a bend section, and the bend section of the second heat exchanger tube can include three or more bends, each of the three or more bends having a corresponding bend angle that is less than or equal to approximately 90 degrees.