| 摘要 |
PROBLEM TO BE SOLVED: To prevent remaining water in a drain tank from being frozen, and surely execute drain by providing means for draining the remaining water in the tank on the drain tank when internal temperature in the tank has become a predetermined temperature or lower. SOLUTION: A hopper 45 includes a water injection solenoid valve 47 for leading hot water from a hot water supply pipe 34b, a drain tank 48 for collecting remaining water when air is separated, a drain tank valve 49, and a negative pressure closing valve 50 and a check valve 51. The drain tank 48 is connected with a circulation pipe line 35 through a drain pipe line 52, on which pipe line 52 there are provided a check valve 53 and a drain solenoid valve 54. The drain tank 48 includes a drain hole 55 for restricting the maximum amount of water and a water level switch 56 for opening/closing the drain solenoid valve 54. Particularly, the drain tank 48 includes drain means 57 which discharges remaining water by opening part of the tank when internal temperature in the drain tank 48 has become a predetermined temperature or lower. |
