| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a water heater 11 capable of defrosting a heat pump unit 75 and enabling antifreeze in a boiling-up circulation passage 70a. <P>SOLUTION: The water heater is equipped with a reheating circuit 53 for circulating hot water of a hot water storage tank 17 in a reheating circulation passage 53a and reheating bath water by a reheating heat exchanger 44, and a boiling-up circuit 70 for circulating the water of the hot water storage tank 17 in the boiling-up circulation passage 70a and boiling up the hot water by the heat pump unit 75. The reheating circuit 53 and the boiling-up circuit 70 merge at a merging part 73, and hot water is returned to the hot water storage tank 17 from one of a plurality of intake passages 52 via a switching valve 48. During a defrosting operation or an anti-freezing operation, the inlet side of the switching valve 48 is closed, and the hot water of the hot water storage tank 17 taken into the reheating circuit 53 is returned to the hot water storage tank 17 through the confluence 73 and the boiling-up circuit 70. The heat pump unit 75 is defrosted by using heat of the hot water in the hot water storage tank 17. The hot water in the hot water storage tank 17 is replaced with water in the boiling-up circulation passage 70a, and freezing in the boiling-up circulation passage 70a is prevented. <P>COPYRIGHT: (C)2009,JPO&INPIT |
