| 摘要 |
PURPOSE:To certainly and automatically prevent water from freezing in a water circulation pipe line, by sensing the water temperature in the part of a pipe line where the temperature is the lowest by a temperature sensor, and by replacing the water in the pipe line by hot water by driving a water circulation pump by a signal from a controller. CONSTITUTION:The temperature in water in a pipe line between the suction port of a water circulation pump 4 and the connecting part 8a of a pipe line with a water feed pipe line 8 is the lowest in the pipe lines 3a and 3b. The lowest temperature is sensed by a temperature sensor 16, by which a signal is fed into a controller 12. The controller 12 drives the water circulation pump 4 when the sensed temperature is under the predetermined value. Driving of the circulation pump 4 flows out cold water remaining in the pipe lines 3a and 3b into a hot water tank 2 or both into the hot water tank 2 and a heat pump unit 1, replacing cold water in the pipe lines 3a and 3b by hot water. After about an hour, the water temperature in the neighborhood of the inlet port of a hot water tank 2 is heightened up above a set value for a temperature sensor 17 to stop water, which feeds a signal into the controller 12. Receiving a signal from the temperature sensor 17, the controller 12 stops driving of the water circulation pump 4. |
