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. - S; ~0 j' V. O8 R
) z3 e% H# W8 J6 q5 kSolution: turn off water supply and take the humidifier apart and clean it will stop the leaking.; t4 V$ f8 y+ V6 S3 I' ]( A* e
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Otherwise, find a professional or change a new set.