Levoit Core 300S Check Filter light: correct reset

The Core 300S Check Filter light is a maintenance reminder. Replace the due filter, then reset the indicator with the correct control. Read the exact indicator before resetting anything: filter, air-quality, network and motor warnings do not mean the same thing. Keep the unit upright with its inlets clear and use only the controls and removable items named in the manual. What the alert means: Levoit estimates filter use over time; the light does not by itself prove that the motor or air-quality sensor has failed. What to distinguish first: Inspect the filter for dirt and odour, and distinguish this maintenance light from the coloured air-quality ring. 1. Confirm the exact symptom — Levoit estimates filter use over time; the light does not by itself prove that the motor or air-quality sensor has failed. 2. Prepare safely — Turn the purifier off and unplug it before opening a cover, cleaning a sensor or touching a filter. 3. Apply the official check — Fit the specified dry replacement filter, close the cover and hold the Sleep Mode button for three seconds to reset the light. 4. Interpret one retest — Confirm the light goes out and airflow sounds normal. If it returns immediately, reseat the cover and contact Levoit. The official Levoit procedure identifies this exact symptom and supports the checks above. Do not wash a non-washable HEPA or carbon filter and keep liquids away from the fan and sensor electronics. Stop and contact support if a motor code remains, the fan does not start or there is heat, smoke or an electrical smell.