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. - w9 z7 t# s' ]( a4 l6 R
3 e7 `! n; F( i. @Solution: turn off water supply and take the humidifier apart and clean it will stop the leaking. " ? `2 m0 u+ b9 t0 T- ?; i3 X! d6 S2 W; C: G, n
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Otherwise, find a professional or change a new set.