A water heater includes a plurality of stages of burners, a water supply pipe, a hot water outlet pipe, a heat exchanger, a passing water quantity control unit, a temperature detection unit, and an operation control unit. The operation control unit, upon confirmation that a predetermined start condition of a passing water restriction is satisfied at a start of a hot water supply, performs the output hot water temperature control by calculating a target flow rate that causes no switching or a minimum count of switching of the combustion stages of the burners and configuring the passing water quantity control unit to have the target flow rate. The operation control unit, upon confirmation that a predetermined release condition of the passing water restriction is satisfied, executes the passing water control in which the passing water quantity is returned to the predetermined water quantity by gradually releasing the passing water restriction.

A water heater includes a plurality of stages of burners, a water supply pipe, a hot water outlet pipe, a heat exchanger, a passing water quantity control unit, a temperature detection unit, and an operation control unit. The operation control unit, upon confirmation that a predetermined start condition of a passing water restriction is satisfied at a start of a hot water supply, performs the output hot water temperature control by calculating a target flow rate that causes no switching or a minimum count of switching of the combustion stages of the burners and configuring the passing water quantity control unit to have the target flow rate. The operation control unit, upon confirmation that a predetermined release condition of the passing water restriction is satisfied, executes the passing water control in which the passing water quantity is returned to the predetermined water quantity by gradually releasing the passing water restriction.

The present disclosure is directed to a tankless water heater and systems and methods of using the same. The tankless water heater embodiments of the present disclosure can be configured to have a plurality of independently operable heat exchangers that can be used individually or collectively, in any combination, to heat water based on the level of demand for hot water. Embodiments can be configured for randomly selecting which heat exchangers are used to heat the incoming water. Embodiments of the present disclosure can also be configured to flow water through heat exchangers that are not being used to heat water and direct such water to a recirculation loop.

A fired heater has two cells segregated by an insulative wall. A first plurality of burners are located in the first cell and a second plurality of burners are located in the second cell. A radiant tube extends from the first cell to the second cell for carrying a fluid material through the heater to heat the fluid material. The flow of fuel to the burners in either the first cell or the second cell can be terminated to accommodate lower heater duty when demand is lower.

A combustion device includes a combustion control section which controls combustion in the combustion device; a setting section operated to set information indicating whether or not a plurality of combustion devices are in a common vent discharge state; and a memory section which stores therein connection configurations with the other combustion control sections to which the combustion control section is communicatively connected, and the combustion control section determines whether or not the combustion control section can communicate with a linkage control section or the other combustion control sections, and inhibits combustion in the combustion device to which the combustion control section belongs, in a case where the combustion control section determines that the combustion control section cannot communicate with the linkage control section or at least one of the other combustion control sections and the common vent discharge state is set by the setting section.

An integrated pressure condensing boiler is provided which relates to the technical field of boilers. The integrated pressure condensing boiler includes a pressure-bearing housing, a heat-exchange furnace arranged in the pressure-bearing housing, a combustion chamber communicating with the heat-exchange furnace and cooling tube groups fixed in the heat-exchange furnace. Heat-exchange medium flows from bottom to top in the pressure-bearing housing and in the cooling tube groups, and exchanges heat with high-temperature flue gas flowing from top to bottom in the heat-exchange furnace, thus achieving a counterflow heat exchanging. The heat-exchange furnace includes a multi-stage heat-exchange chamber with each heat-exchange chamber being cylindrical. The heat-exchange chambers are arranged in sequence from top to bottom to achieve a flue gas diffusing manner that high-temperature flue gas diffuses from center part to periphery and then gathers from periphery to center part.

An integrated pressure condensing boiler is provided which relates to the technical field of boilers. The integrated pressure condensing boiler includes a pressure-bearing housing, a heat-exchange furnace arranged in the pressure-bearing housing, a combustion chamber communicating with the heat-exchange furnace and cooling tube groups fixed in the heat-exchange furnace. Heat-exchange medium flows from bottom to top in the pressure-bearing housing and in the cooling tube groups, and exchanges heat with high-temperature flue gas flowing from top to bottom in the heat-exchange furnace, thus achieving a counterflow heat exchanging. The heat-exchange furnace includes a multi-stage heat-exchange chamber with each heat-exchange chamber being cylindrical. The heat-exchange chambers are arranged in sequence from top to bottom to achieve a flue gas diffusing manner that high-temperature flue gas diffuses from center part to periphery and then gathers from periphery to center part.

A scalable pulse combustor that can be deployed as the heat exchanger in high efficiency, low NOx condensing boilers, water heaters and steam generators is provided. The combustor generally comprises an annular burner coil with a burner flange for accommodating the nozzle of a conventional burner/blower fitted into the central aperture thereof; a spaced-apart opposite annular spreader coil with a heat exchange hub fitted into the central aperture thereof; and a plurality of annular intermediate coils. Each of the burner, spreader and intermediate coils are preferably formed of spiral wound stainless steel tubing, with each winding directly abutting the preceding winding so as to create an annular wall. The heat exchange hub functions as a secondary heat exchanger with its own independently controllable coolant flow.

A scalable pulse combustor that can be deployed as the heat exchanger in high efficiency, low NOx condensing boilers, water heaters and steam generators is provided. The combustor generally comprises an annular burner coil with a burner flange for accommodating the nozzle of a conventional burner/blower fitted into the central aperture thereof; a spaced-apart opposite annular spreader coil with a heat exchange hub fitted into the central aperture thereof; and a plurality of annular intermediate coils. Each of the burner, spreader and intermediate coils are preferably formed of spiral wound stainless steel tubing, with each winding directly abutting the preceding winding so as to create an annular wall. The heat exchange hub functions as a secondary heat exchanger with its own independently controllable coolant flow.

A water heater includes a plurality of stages of burners, a water supply pipe, a hot water outlet pipe, a heat exchanger, a passing water quantity control unit, a temperature detection unit, and an operation control unit. The operation control unit, upon confirmation that a predetermined start condition of a passing water restriction is satisfied at a start of a hot water supply, performs the output hot water temperature control by calculating a target flow rate that causes no switching or a minimum count of switching of the combustion stages of the burners and configuring the passing water quantity control unit to have the target flow rate. The operation control unit, upon confirmation that a predetermined release condition of the passing water restriction is satisfied, executes the passing water control in which the passing water quantity is returned to the predetermined water quantity by gradually releasing the passing water restriction.