| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a storage water heater capable of more securely reducing shortage of hot water. <P>SOLUTION: Remaining hot water amount detection means 71-75 for detecting the amount of remaining hot water within a hot water storage tank 100 are provided in the hot water storage tank 100. A midnight operation mode for performing boiling up operation only in the midnight time zone is programmed in a control device E beforehand. The control device E calculates remaining usable time which is time until hot water is run short of, based on predicted hot water supply amount calculated from supplied hot water use conditions of a user and the hot water remaining amount, when the amount of remaining hot water detected by the remaining hot water amount detection means 71-75 is below first predetermined amount in the midnight operation mode, and issues hot water shortage prior warning with respect to the user when the remaining usable time is below predetermined reference time. After the hot water shortage prior warning is issued, when the amount of remaining hot water within the hot water storage tank 100 detected by the remaining hot water amount detection means 71-75 is below second predetermined amount smaller than the first predetermined amount, the control device E issues hot water shortage imminent warning with respect to the user. <P>COPYRIGHT: (C)2010,JPO&INPIT |
