3 L top-fill ultrasonic cool-mist humidifier with a control knob, refill indicator, automatic low-water stop, 360° nozzle, and user-serviceable water filter sponge.
Choose the observed symptom, light, code, app state, or output problem.
On the Dual 150, turn the mist knob higher and then check the water path before assuming the ultrasonic element failed. The manual separates an empty tank from excess water in the base chamber, and also calls out a blocked bottom air inlet, nozzle obstruction, an unlevel surface, very cold water, detergent residue, and a dirty water filter assembly.
Dry the Dual 150 and identify where new water first appears before treating every wet surface as a tank leak. The manual points to the silicone sealing ring around the water outlet valve, high room humidity, water left around the base, shaking or moving a full unit, an unlevel surface, and a leaking tank.
If the Dual 150 refill light stays on after the tank is filled, reseat the tank and then check the user-serviceable water filter assembly. The manual does not call for bypassing or manually holding the water-level sensor down.