An assembly for a water heater having a burner includes a tube extending longitudinally along a centerline from a first end adjacent the burner to a second end. The first end includes a flared portion extending away from the centerline. A partition is provided downstream of the burner and includes an opening having a curved flange defining an opening for receiving the flared portion of the tube.

A fire tube with three hollow tube sections, two of which are parallel to each other and one of which is perpendicular to and connects the ends of the first two tube sections. The bottom-most tube section, which contains the burner, has an inner ceramic liner that is made up of one or more separate ceramic tubular sections. An upper set of cooling funs surrounds the top part of the bottom-most tube section, and a lower set of cooling fins surrounds the bottom part of the bottom-most tube section.

A fire tube with three hollow tube sections, two of which are parallel to each other and one of which is perpendicular to and connects the ends of the first two tube sections. The bottom-most tube section, which contains the burner, has an inner ceramic liner that is made up of one or more separate ceramic tubular sections. An upper set of cooling funs surrounds the top part of the bottom-most tube section, and a lower set of cooling fins surrounds the bottom part of the bottom-most tube section.

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 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.

Disclosed is an air heating apparatus including a burner configured to cause a combustion reaction, a main passage, through which water flows while circulating, a heat exchanging device configured to receive heat from combustion gas generated by the combustion reaction and heat the water flowing along the main passage, a heating heat exchanger configured to receive the water heated by the heat exchanging device and exchange heat with the air for heating, a fan configured to send the air to the heating heat exchanger, and a hot water discharge port connected to the main passage such that the water heated by the heat exchanging device is discharged to an outside of the main passage.

Disclosed is an air heating apparatus including a burner configured to cause a combustion reaction, a main passage, through which water flows while circulating, a heat exchanging device configured to receive heat from combustion gas generated by the combustion reaction and heat the water flowing along the main passage, a heating heat exchanger configured to receive the water heated by the heat exchanging device and exchange heat with the air for heating, a fan configured to send the air to the heating heat exchanger, and a hot water discharge port connected to the main passage such that the water heated by the heat exchanging device is discharged to an outside of the main passage.

Disclosed is an air heating apparatus including a burner that causes a combustion reaction, a main passage, through which water flows while circulating, a heat exchanging device that receives heat from combustion gas generated by the combustion reaction and heats the water flowing along the main passage, a heating heat exchanger that receives the water heated by the heat exchanging device and exchanges heat with the air for heating, a fan that blows the air to the heating heat exchanger, and an expansion tank disposed in the main passage to accommodate a change in a volume of the water and having an expansion opening opened to an outside.

Disclosed is an air heating apparatus including a burner that causes a combustion reaction, a main passage, through which water flows while circulating, a heat exchanging device that receives heat from combustion gas generated by the combustion reaction and heats the water flowing along the main passage, a heating heat exchanger that receives the water heated by the heat exchanging device and exchanges heat with the air for heating, a fan that blows the air to the heating heat exchanger, and an expansion tank disposed in the main passage to accommodate a change in a volume of the water and having an expansion opening opened to an outside.

A conduit fitting for an exhaust duct includes a conduit and a condensate trap. The conduit fitting defines an interior space partitioned into an upper conduit and a lower condensate reservoir. The condensate reservoir can be configured to contain a neutralizing agent for neutralizing acidic condensate prior to it exiting the reservoir.