| 摘要 |
<p>PURPOSE:To improve the economical property of the water heater much more by a method wherein the time of conduction of a daytime electric heater is permitted to set so as to conform with the actual using condition of an user. CONSTITUTION:When midnight electric power is stopped, a midnight electric power detecting circuit 10 outputs midnight electric power stopping signal. A midnight electric heater control circuit 19 opens a relay 20 to stop the conduction of a night electric heater 4 and, at the same time, a timer circuit 16 starts the operation of a timer. A daytime electric heater control circuit 17 controls the conduction of a daytime electric heater 5 as far as the midnight electric power stopping signal from the detecting circuit 10 and the timer operating signal from the timer circuit 16 are existing. When the timer circuit 16 outputs the timer stopping signal, a control circuit 17 holds the relay 18 in an opened condition and stops the conduction of the daytime electric heater 5. The conduction time of the daytime electric heater 4 may be elongated by increasing the operating volume of a time setting unit 21 while it may be shortened by decreasing the same.</p> |
