| 摘要 |
<p>PURPOSE:To reduce the consumption of power and a corrosion-proof device by providing detection means for detecting the time of using or unusing, and changing over a corrosion proof device to reduce its corrosion output when detection means for detecting the unusing time has detected the unusing time. CONSTITUTION:Hot water stored in a water heater is set at a volume sufficient for not causing runout of hot water under normal using condition, and hot water constantly remains at the upper part of a tank 2. By detecting the temperature of hot water by means of a thermostat or a heat sensitive element 10, where it reaches more than a predetermined temperature (atmospheric temperature and feed water temperature), it is discriminated that power is supplied to a heating unit 5 and is heated and used. On the other hand, when the temperature of hot water is less than a predetermined temperature, it is detected that it is the unusing time, and the power source of a corrosion proof electrode 3 is opened by the heat sensitive element 10. Accordingly, since the corrosion resistance at the time of unusing becomes a corrosion resistance only by a corrosion resistance due to a corrosion proof rod 9, it is possible to rationalize the corrosion resistance at the time of unusing. Since the corrosion proof rod 9 does not require a power source separately, the corrosion proof effect can be maintained even if the corrosion resistance power source is turned 'cut' erroneously.</p> |
