| 摘要 |
<p>PURPOSE:To permit to obtain hot-water having a desired temperature within preset objective time economically with good heating efficiency by switching fist heating means to second heating means at a proper time. CONSTITUTION:In the water heater provided with the heating source having the first heating means, whose heating capacity is fluctuated, and the second heating means, whose heating capacity is stabilized, and switching control of said heating means is effected. The switching control is effected by a method wherein heating is effected by the first heating means after setting the objective time and temperature of finish of heating previously and subtracting process of the temperature of water in a hot-water reserving tank, which is detected by a water temperature detecting unit 1, and the objective temperature is effected in a subtracting circuit 3. On the other hand, a remaining time until the objective time is operated in an operating unit 4 while this remaining time and the second heating capacity are processed by integrating in a circuit 5. The temperature, obtained by this process, and the temperature difference, obtaind by the circuit 3, are compared and decided in a comparator 6, and the first heating means is switched to the second heating means by a switching unit 7 when the temperature difference, obtaind by the circuit 3, has become larger.</p> |
