| 摘要 |
PURPOSE:To provide a highly accurate water level sensing device by computing the water level in the water level computing section from the difference between the signal from a pressure sensor and the stored reference value by detecting that portion of pressure which has leveled after the hot water delivery was started, said pressure being stored in the reference pressure memory section, and detecting the pressure build-up thereafter. CONSTITUTION:Upon reception of command for starting hot water delivery through a control button, a three-way valve 13 is switched to the (b) side by a water level control section 22 to start the hot water delivery to a bath tub 11 through a hot water supply passage 14, a pump 15 and a supply pipe 16, and one end of a return pipe 12 si closed at the same time by the three-way valve 13. While the water level remains in the (c) range after the start of hot water delivery, the signal from a pressure sensor 17 maintains a constant level as shown by (d), and the leveling sensing section detects a lack of change in pressure over a certain time interval (t) and transmits it to the reference pressure memory section. When the water level enters the (e) range thereafter, the signal from a pressure sensor 17 increase with the increase of the water level, and the pressure build-up sensing section picks up the rising water level at the moment (g). The water level computation section 21 determines the difference between the signal from the pressure sensor 17 and the stored value in the reference value memory section 20, and the water level signal is transmitted to the water level section. Therefore, the water level in the bath tub can be accurately detected.
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