Musty or moldy odor from the air conditioner when it starts or while running.

Safety first: Unplug the unit. Wear gloves and a mask if you are sensitive to mold.

Steps to remove odors:

• 1. Clean or replace filter: Wash the filter thoroughly or replace it if heavily stained or damaged.
• 2. Access evaporator coil: Remove the front cover and inspect the coil. Spray with a foaming coil cleaner designed for AC units. Allow it to work, then rinse lightly if the product requires.
• 3. Clean drain pan: Wipe out the condensate pan under the coil with a mild bleach solution (1 part bleach to 10 parts water) to kill mold and bacteria. Rinse and dry.
• 4. Clear drain path: Ensure the drain holes and hoses are free of slime and debris so water does not stagnate.
• 5. Run fan-only mode: After cleaning, run the unit in FAN mode for 30–60 minutes to help dry the coil and pan.
• 6. Prevent recurrence: Clean the filter monthly during heavy use and periodically run the fan after cooling to dry out moisture.