| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a hot water storage type water heater capable of preventing rapid fluctuation of a hot water supply temperature when freezing prevention operation of a boiling water circulation passage is carried out during hot water supply action. <P>SOLUTION: When carrying out the freezing prevention operation of the boiling water circulation passage during the hot water supply action, a four way valve 32 is controlled such that a valve element 32h rotates from a position (a valve element position of 90°) communicating a boiling heat exchanger 62 with tank return piping 44 via the boiling water circulation passage, through a position (a valve element position A°) communicating the boiling heat exchanger 62 with a hot water storage tank 10 via the boiling water circulation passage, to the position (the valve element position 90°) communicating the boiling heat exchanger 62 with the tank return piping 44 via the boiling water circulation passage. Hereat, the time required for rotating the valve element 32h from a start position to an end position is prolonged in comparison with when freezing prevention operation of the boiling water circulation passage is requested during non-execution of the hot water supply action. <P>COPYRIGHT: (C)2013,JPO&INPIT |
