Diagnosis
Severely restricted airflow. The main particle filter is saturated and clogged, or the pre-filter is excessively dirty.
How to Fix It
Check the filter runtime. The indicator is based on a 12-month timer from last reset, not actual air quality. If it's been over a year, replace the filter. If time remains, perform a visual inspection: remove the filter. Hold it up to a bright light. If little to no light passes through the pleated media, it is clogged and must be replaced.
If That Didn't Work
Remove the fabric pre-filter sleeve and wash it in warm water with mild detergent. Rinse thoroughly and let it air dry completely before reinstalling. A dirty pre-filter blocks airflow before it even reaches the main filter.
Heads Up
Do not vacuum or tap the main filter to clean it. This damages the electrostatic media and releases captured particles. It is not cleanable.