| 摘要 |
PROBLEM TO BE SOLVED: To provide a water heater capable of contributing to energy saving while supplying hot water at the timing a user desires, and to provide a cogeneration system, and a method for operating a water heater.SOLUTION: A water heater 2 includes: a hot water storage tank 10; an outlet hot water temperature detector 14; a hot water temperature adjustment unit 12; an operation device 15; and a control device 13. The control device 13 calculates a reference hot water supply temperature Tr based on an outlet hot water temperature, and controls, based a first mode in which a temperature closest to the reference hot water supply temperature Tr serves as a target hot water supply temperature, a hot water temperature adjustment unit within a permissible set temperature range in which a first set temperature T1 is set as an upper limit, and a set temperature obtained by subtracting a predetermined balance &Dgr;T from the first set temperature T1 is set as a lower limit. |
