| 摘要 |
PURPOSE:To permit to detect the amount of water in the bathtub automatically by providing a micro-computer type control circuit equipped with a thermistor for detecting water temperature, a water amount sensor and a timer. CONSTITUTION:When the operating switch of a remote control box 14 is put ON, a circulating pump 5 is operated and water in the bathtub 13 is circulated, the water temperature (t0) in the bathtub 13 is detected by the thermistor 3 and the amount of circulating water (l/min) is detected by the water amount sensor 4. After T min, the thermistor 3 detects hot-water temperature (t1) and the thermistor 7 detects hot-water temperature (t2). When it is assumed that the water amount in the bathtub is L(l) and the amount of heat, absorbed by a heat exchanger 6, is equal to the amount of heat obtained by water in the bathtub, the initial amount of water in the bathtub 13 can be detected by the micro-computer. As a result, the shortage amount of water to the full capacity of the bathtub can be determined and, therefore, the amount of water to be supplemented from a hot-water supplying unit may be taken out as an electric signal. |
