| 摘要 |
PURPOSE:To disable from delivering hot water out of a hot water storage tank when heat transfer medium mixes in service hot water and consequently prevent from drinking accidentally and ensure safety and improve the heat transfer performance by removing the thermal contact resistance at a heat exchanger for hot water supply by a structure wherein an automatic shut-off valve is arranged in a feed water pipe communicating to the hot water storage tank and an automatic drain valve is arranged in a drain pipe. CONSTITUTION:If the leakage of flon refrigerant (such as F-12, F-22) acting as the heat transfer medium in a heat pump cycle occurs, the pressure in a low pressure circuit drops during the operation on heat pump cycle. A pressure detector 20 senses said abnormal low pressure and not only closes an automatic shut-off valve 16 so as to stop the inflowing of feed water through a feed water pipe 10 and check the outflowing of hot water through a hot water delivery pipe 11 but also opens an automatic drain valve 17 so as to drain the water in a hot water storage tank 7. In this case, said drainage is smoothly performed, because a vacuum breaker 18 is brought into actuation so as to flow the air in the hot water storage tank 7. On the other hand, when a pressure detector 21 provided on the hot water storage tank 7 senses an abnormal pressure rise in the tank 7, the similar action as done by the pressure detector 20 is also performed. |
