① Has the filter replacement period elapsed?
→ The service life of the filter is reached in about half year to a year, depending on the operating environment.
② Is the unit used in a room that is larger than its rated capacity?
→ The service life of the filter may be reached earlier if the unit is used in a room that is larger than the rated capacity of the unit.
③ Is the air inlet or outlet of the base unit, or the pre-filter contaminated?
→ Clean the unit to clean contamination from the air inlet or outlet, as well as the pre-filter. If the conditions do not improve even after cleaning the unit, replace the filter with a new one.
④ Is the unit operating in a room with strong odor?
→ Operating the unit in a room with strong odor from cigarette smoke or cooked meat for long hours can lead to short life and earlier replacement of filters. When operating the unit in such an environment, periodical ventilation of the room is recommended.
If it is difficult to resolve the problem through means such as the one described above, dry the filter for a day under the sun. (This is not a promise of performance recovery.)