It is possible that the shut-off valve was blocked by the cumulated white stuff. As a result, water supply can not be stopped even when water level is high. ; X4 z& k; i& A- I. @/ V; h: D( K0 h: i! A9 H/ b: R7 H
Solution: turn off water supply and take the humidifier apart and clean it will stop the leaking.& ]8 F2 \ ]2 o
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Otherwise, find a professional or change a new set.