| 摘要 |
PROBLEM TO BE SOLVED: To prevent a phenomenon in which impurities such as magnesium or the like is adhered to a sidewall, piping or the like of a heating tank due to a precipitation of the impurities from a remaining water in the tank. SOLUTION: A scale storage chamber 5 having a filter 8 for communicating with the heating tank 2 via a drain tube 10 having an opening/closing valve 11 is attached to a body 1. When a cumulative value of an operating time arrives at a previously set time, the valve 11 is opened, and the remaining water in which a concentration of the impurities remaining in the tank 2 becomes high is drained to the chamber 5 via the tube 10. |
