| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a water heater for reconciling maximal size reduction in a hot water storage tank and security of use of supply hot water in a required quantity and a hot water temperature while using natural energy having high energy consumption efficiency by a heat pump circuit. <P>SOLUTION: The hot water storage tank 12 stores the supply hot water heated by heat exchange by heat in a condensing process of the heat pump circuit 13. A switching valve 17a is interposed in a hot water supply passage 17, and a hot water supply source can be switched to the hot water storage tank side or the hot water introducing passage 18 side. Connecting terminals 112 and 212 detect the connection by whether or not an external hot water supply passage 8 of a backup water heater 2 being an instantaneous water heater is connected to a hot water introducing passage. When the connection is not detected, hot water is supplied to a hot water supply plug 4 or a bathtub 7 only from the hot water storage tank. While, when the connection is detected, the hot water is supplied from the hot water storage tank as far as suppliable hot water exists on the basis of a hot water temperature sensor 123. When the hot water runs out, the switching valve is switched to the hot water introducing side, and the hot water is supplied after introducing the hot water from the backup water heater. <P>COPYRIGHT: (C)2004,JPO |
