| 摘要 |
PURPOSE:To prevent water from overflowing from a heating tank, and also, to suppress the variance of the extraction quantity of hot water to the minimum by detecting the water level of a somewhat upper level then the level in which the upper electrode part starts a siphon effect, before a prescribed time of a timer circuit elapses, when feed water pressure is high, and executing the closing valve control of a feed water solenoid valve. CONSTITUTION:In the case feed water pressure is normal or low, the water level of a heating tank 2 ascends by feed water, and when it reaches a somewhat lower level than the level for starting a siphon effect, it is detected by the lower electrode part 13, and a control circuit 17 closes a relay switch 15. As a result, a timer circuit 21 starts, and when a prescribed time (for instance, three seconds) elapses, a time switch 21A is closed and a second relay 22 is excited. In the case the feed water pressure is high, before the timer circuit 21 becomes time-up, an electric conduction to a feed water solenoid valve 10 is disconnected forcibly by the upper electrode part 14, therefore, water overflow from a detecting tube 12 of the heating tank 2 can be prevented, and also, the increase of the extraction is suppressed, and an excessive variance of the extraction quantity can be prevented. |
