| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a water heater securely filling a lower part of a first hot water storage tank 11 with hot water and storing hot water of temperature as high as possible in a second hot water storage tank 12. <P>SOLUTION: The lower part of the first hot water storage tank 11 and an upper part of the second hot water storage tank 12 are directly interconnected by a connection line 13. Water taken out of the lower part of the hot water storage tank 12 is boiled up by a heat pump unit 14, and the boiled hot water is returned to the upper part of the first hot water storage tank 11 by a four-way valve 20. The temperatures detected by a remaining hot water detection sensor S3 provided in the lower part of the first hot water storage tank 11 and by a remaining hot water detection sensor S4 provided in the upper part of the second hot water storage tank 12 exceed a predetermined detection temperature, respectively, a route for returning boiled hot water is switched to the upper part of the second hot water storage tank 12 by the four-way valve 20. After switching the route, no hot water flows in the connection line 13, to reduce thermal loss of the hot water due to heat release in the connection line 13. <P>COPYRIGHT: (C)2010,JPO&INPIT |
