The unit is likely overheating due to a clogged filter or blocked air intake.
- First, check the filters. A severely dirty True HEPA or carbon pre-filter restricts airflow, causing the motor to overheat and the safety shut-off to engage. Replace them if they look dark or clogged.
- Clear all vents. Ensure there's at least 6 inches of clearance on all sides, especially the rear intake and top exhaust. Never place it in a corner, under a shelf, or against curtains.
- Check the environment. Operating in a very hot room (above 104°F/40°C) can trigger thermal protection. Move it to a cooler location.
IF THAT DIDN'T WORK: The internal thermal fuse may have been tripped. Unplug the unit for at least 60 minutes to let it cool down and reset completely, then try again in a well-ventilated area.