| 摘要 |
<p>PROBLEM TO BE SOLVED: To block the useless execution of freezing prevention control in a drained state, in a water boiler comprising: a water circuit 3 for running water through the circuit by opening a water valve 33; a water heating part 4 for heating the water flowing through the water circuit; and control means 5, using a battery 51 as an electric power supply, in which the control means is started, when the temperature of the water circuit is reduced lower than a prescribed freezing dangerous temperature, so as to execute the freezing prevention control.SOLUTION: The control means 5, even when the temperature of the water circuit 33 is reduced lower than a prescribed freezing dangerous temperature so that the control means 5 is started, if draining operation is performed, does not execute the freezing prevention control so as to cutoff the electric power supply.</p> |
