Patent ID: 7058457

Claim:
A hot water supply system operated by linking plural water heaters, comprising: system controllers centralizing controls of a group of water heaters, and host system controllers centralizing controls of a group of system controllers, wherein said host system controllers are disposed hierarchically so that the controllers may be finally centralized in a single highest host system controller, and the highest host system controller controls the operation of individual water heaters through the lower system controllers, wherein said lower system controllers to which water heater are connected are designed to increase or decrease the number of operating units of a group of water heaters under the control depending on the tapping request, while the highest host system controller controls the number of operating units of water heaters in the entire system by increasing or decreasing the number of operating units of lower system controllers and wherein said highest system controller controls to determine the operation stopping timing of the water heaters centralized by one lower system controller, depending on the number of operating units of water heaters centralized by other lower system controllers.