HOT WATER SUPPLY DEVICE

PROBLEM TO BE SOLVED: To further improve heat efficiency of a hot water supply device without generating dew condensation inside of a can body. SOLUTION: When a hot water supply set temperature is a control switch temperature or less, a can body target temperature to achieve a prescribed flow rate ratio of a can body-side flow rate and a bypass-side flow rate is determined on the basis of the hot water supply set temperature and a water inflow temperature, in a case when the can body target temperature is higher than a lower limit value of a can body temperature, combustion of a gas burner 31 is controlled so that the detected can body temperature reaches the can body target temperature, and an opening of a bypass water amount adjusting valve 18 is adjusted so that a hot water supply temperature reaches the hot water supply set temperature, and in a case when the can body target temperature is the lower limit value of the can body temperature or less, the combustion of the gas burner 31 is controlled so that the can body temperature reaches the lower limit value, and the opening of the bypass water amount adjusting valve 18 is adjusted so that the hot water supply temperature reaches the hot water supply set temperature. The lower limit value of the can body temperature is set by each stage of heating capacity of the gas burner 31 under consideration of a can body dew condensation temperature in each stage of heating capacity of the gas burner 31. COPYRIGHT: (C)2010,JPO&INPIT