| 摘要 |
PURPOSE:To restrict a generation of noise and reduce a charge of fee for consumed electricity by a method wherein a circulation pump is intermittently operated when a low temperature is found under an additional heating of the bath boiler. CONSTITUTION:When a low temperature condition is found under a non- additional heating being performed, a circulation pump 4 is operated if an anti-freezing switch 5 arranged at a return pipe 5a extending from a bath tab 1 is decreased lower than a temperature T2, and the circulation o the water in the bath tab makes the freezing of the water to be prevented. At this time, when the anti-freezing switch 5 is turned ON, a timer 7a assembled in a control device 7 is operated to turn ON or OFF the circulation pump 4 within a range in which freezing can be prevented. Thereby, it is made possible to reduce the operation time of the circulation pump 4 during the ON time of the antifreezing switch 5. |
