A water heating system includes a plurality of water heaters of which exhaust paths are connected in common to an exhaust path assembly, a control device configured for centralized control of the plurality of water heaters, and a non-volatile storage unit. The plurality of water heaters include control units configured to control hot water supply operations based on communication with the control device, respectively. The storage unit is configured to store information on the water heater of which control unit is recorded to have established communication with the control device. The control device turns off all of the plurality of water heaters when information on the water heater of which control unit has currently established communication with the control device does not match with the information stored in the storage unit.

A water heating system having a system inlet pipe (1.002), a hot water delivery pipe (1.003) and a hot water return pipe (1.006) connected to a building hot water distribution network (1.024); the water heating system including one or more water heaters (1.001), the or each water heater having a heater inlet (1.022) and a heater outlet (1.023), a hot water return pipe (1.006) connected between the system inlet and delivery outlet via the building hot water distribution network to form a close loop hot water supply-return circuit; a pump (1.005) connected to circulate water through the hot water supply-return circuit whereby the pump can circulate water through one or more of the water heaters; a valve means (1.007) a first non-return valve adapted to prevent inlet water (water delivered to the system inlet) from flowing into the hot water return pipe or the building hot water distribution network.

A hot water supply system provided on a water pipeline, which includes a water inflow side and a water outlet side. The hot water supply system includes a plurality of water heaters; each includes a conduit, a heating device, a calculating unit, and a control unit. The conduit includes an inlet section, an outlet section, and a heating section in sequence, wherein the inlet section and the outlet section are connected with the water inflow side and the water outflow side respectively; the heating device heats the heating section; the calculating unit estimates a heating workload needed. If the heating workload of any water heater exceeds a predetermined upper limit workload thereof, the control unit of one water heater controls the other idle heating device to heat water, which ensures that water temperature of water provided to the water outflow side would reach a demanded water temperature.

A combined combustion device comprises: a plurality of combustion units (2) each having a burner (4) and an air supply fan (5); an exhaust collecting pipe (10) connecting the plurality of the combustion units (2) to each other; and a check valve (7) which opens by rotation of the air supply fan (5) and prevents backflow of combustion exhaust gas from the exhaust collecting pipe (10) into each of the combustion units (2), wherein when one or more of the combustion units (2) among the plurality of the combustion units (2) are in a combustion operation state and the other one or more of the combustion units (2) are continuously maintained in a non-combustion operation state for a predetermined reference stoppage time or longer, the air supply fans (5) of the other one or more of the combustion units (2) are rotated for a certain time.

An energy exchange system employing a hot water loop, a chilled water loop, an energy exchanger, a boiler plant for heating water flowing through the hot water loop and for heating water flowing through the chilled water loop via the energy exchanger, a chiller plant for chilling the water flowing through the chilled water loop and for chilling the water flowing through the hot water loop via the energy exchanger, and a control for calculating a hot energy load for operating the at least one boiler to heat the water flowing through the hot water loop and for heating the water flowing through the chilled water loop via the energy exchanger, and for calculating a chilled water energy load for operating the at least one chiller to chill the water flowing through the chilled water loop and for chilling the water flowing through the hot water loop via the energy exchanger.

A multi-pipe-switching heat exchange apparatus has a heating module, an auxiliary module, a buffering module, and an operation module. The heating module has at least one heating boiler. The auxiliary module is deposited beside the heating module and has at least one spare boiler. The buffering module is connected to and communicates with the heating module and the auxiliary module, and has a buffering body connected to and communicating with the at least one heating boiler and the at least one spare boiler, a first pipeline set deposited between the buffering body and the heating module, and a second pipeline set deposited between the buffering body and the auxiliary module. The operation module is connected to and communicates with the buffering module and has an operation end and a third pipeline set connected to and communicating with the buffering body and the operation end.

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 immediate hot-water supplying system 1 includes a P hot water supply device 10 configured to heat water flowing through a first supply pipe 2, an N hot water supply device 30 configured to heat water flowing through a second supply pipe 3, a check valve 6, and a coupled controller 60 configured to, when the flow amount detected by a second flow amount sensor 34 is equal to or more than a hot-water-supply detection flow amount, perform a hot-water supply operation in which a first burner 12 or a second burner 32 is burned with a circulation pump 16 stopped, and when the flow amount detected by the second flow amount sensor 34 is less than the hot-water-supply detection flow amount, perform a circulation heat keeping operation in which the first burner 12 is burned with the circulation pump 16 activated.

A hydronic heating system employing comprises a water line, two or more boilers, and a control. In operation, the water line facilitates a circulation of water through a building and the boilers heat the water as the water flows through the water line. The control calculates a system energy load for operating boilers. The calculation of the system energy load is a function of a set-point water temperature for the hydronic heating system, a supply water temperature of water flowing relative to a supply point of the water line, a return water temperature of water flowing relative to return point of the water line and a flow rate of water flowing relative to a flow sense point of the water line.

A combined heating system comprising a first heating subsystem including a first fluid conductor, a first heating unit adapted to heat a first fluid and output the first fluid at the outlet of the first fluid conductor, and a fluid mover adapted to move the first fluid through the first heating unit, a second heating subsystem including a second fluid conductor adapted to receive a second fluid, a third fluid conductor, a second heating unit adapted to heat the second fluid and output the heated second fluid in the third fluid conductor, a fluid mover adapted to move the second fluid from the outlet of the third fluid conductor to the inlet of the second fluid conductor, at least one heat exchanger operably connected to a downstream location of the first heating unit and a fourth fluid conductor connecting the second fluid conductor and the third fluid conductor.