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. 4 {1 H( _5 X' t- b% v" s/ l6 g
4 I# \( c7 q! a! S0 XSolution: turn off water supply and take the humidifier apart and clean it will stop the leaking.. j' t: e/ N E) H
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Otherwise, find a professional or change a new set.