| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem wherein hot water shortage easily occurs during the day since boiling operation practically does not progress when dropping of an outside air temperature is detected and hot water flowing out from a water heat exchanger is changed over to a bypass passage for preventing freezing of the bypass passage, and hot water of a quantity filling a hot water storage tank can not be boiled within a predetermined time, particularly at night. <P>SOLUTION: When bath reheating is not used, the outside air temperature drops to almost freezing, and an outside air temperature detecting part 11 detects a predetermined set temperature or less, operation of a tank side bath reheating circulating pump 9 is carried out, and heat-exchanged hot water from a bath reheating heat exchange part 8 and the tank side bath reheating circulating pump 9 is passed through a check valve 19, and connected between a selector valve 18 and a hot water storage tank lower part. By this, piping between the selector valve 18 and the tank lower part is prevented from freezing. <P>COPYRIGHT: (C)2007,JPO&INPIT |
