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. 9 g0 _- W ?/ F! M$ J, v
/ L* u3 _* R+ v0 y1 cSolution: turn off water supply and take the humidifier apart and clean it will stop the leaking. : X8 c1 B( d1 a" F1 t$ u; F& _4 P4 ~4 [5 u# Z
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Otherwise, find a professional or change a new set.