Diagnosis
You're talking about the main rear air filter. It's a washable foam filter that gets clogged with dust, reducing airflow and efficiency.
How to Fix It
Clean it monthly during peak use. Here's the fastest method:
- Unplug the unit. The filter cover is the entire large plastic grille on the back.
- Press the two plastic release tabs at the top of the grille inward and pull the top of the grille toward you. It will hinge downward.
- Lift the foam filter out.
- Rinse it under lukewarm tap water until the water runs clear. Gently squeeze out excess water—don't wring or twist it.
- Let it air dry completely for 24 hours before reinstalling. Never run the unit without the filter.
If That Didn't Work
If the foam filter is torn or degraded (common after a few years), you need a replacement (part number is usually on the filter frame). Search for "De'Longhi PACEL290HLWKC replacement filter."
Heads Up
Do not use detergents or brushes on the foam filter. It can dissolve the adhesive that holds the foam layers together. Just water.