| 摘要 |
PROBLEM TO BE SOLVED: To avoid supply of high temperature hot water upon starting of hot water supply even when mixing means such as a mixing valve has a trouble in the state where it is opened on the side of a hot water supply heat exchanger by controlling the mixing means and a bypass valve such that upon the starting of hot water supply water is supplied to a hot water supply passage through a bypass passage and an auxiliary bypass passage. SOLUTION: During waiting of hot water supply prior to hot water supply operation, a water proportional valve 18 on a hot water supply passage 9 is kept at an open state, and a solenoid valve 16 of an auxiliary bypass passage 14 is kept at an open state, and further an opening of a mixing valve 15 is kept to a previously set opening. To be concrete, a valve disk of the mixing valve 15 is kept at a predetermined position such that a mixing ratio represented by hot water amount/(hot water amount + water amount) becomes about 0.5. Thus, even when a hot water supply plug is opened in the state where high temperature hot water is existent in a heat transfer pipe 3 of a hot water supply heat exchanger 1, water is supplied to the hot water supply passage 9 through a bypass passage 13 and the auxiliary bypass passage 14 and hence high temperature hot water from the hot water supply cock is prevented from being discharged. |
