| 摘要 |
<p>PURPOSE:To eliminate the generation of gas caused by the electrolysis of water and prevent the heating low level water by inhibiting an electric power supply to a heater in a case where strain detected by a strain sensor for detecting the expansion strain of a tank shows that a water level in the tank has been lowered. CONSTITUTION:A temperature control means 18 outputs an on- and off-signal for the supply of power to a heater 12 on the basis of a hot-water temperature in a tank 11. The base of a transistor 19 receives an output signal from the temperature control means 18 via the contact of a strain sensor 14, and a relay coil 20 is actuated by the transistor 19, and the relay contact of the relay coil 20 switches on and off the supply of power to the heater 12. According to an increase in the volume of water in the tank 11, the strain sensor 14 detects strain caused by the expansion of the tank 11 to close its contact being an output unit, and when water in the tank 11 is decreased, the strain sensor 14 opens the contact because the amount of strain of the tank 11 is small. In a case where a water level in the tank 11 is lower than H2, the signal from the temperature control means 18 is not inputted into the transistor 19 because the contact of the strain sensor 14 is opened. Accordingly, the electric power supply to the heater 12 is inhibited, and the heating low level water can be prevented.</p> |
