There is a float (a floating ball) inside your Philips Humidifier’s tank. When the water level becomes low, the float activates a water level switch, and this will activate the indication.

This floating ball can be stuck and fail to activate the water level switch. When this happens, your humidifier will not display a low water indicator. 

Also, the stuck floating ball may not float up and cause indicator light to be on constantly after refilling. You can solve this by moving this floating ball with your hand. 


If the above did not help solve the issue, please contact us for further assistance.