Unit runs but does not cool the room effectively; air from outlet is only slightly cooler than room air.

Safety: Unplug the unit before cleaning or opening panels. Refrigerant work must be done by a licensed technician.

• Check mode and setpoint: Ensure the unit is in COOL mode and the set temperature is at least 5°F (3°C) below room temperature.
• Clean air filter: Remove and wash the filter with mild soap and water. Let it dry completely before reinstalling.
• Clean coils: Access the evaporator (indoor) and condenser (outdoor/exhaust) coils. Use a soft brush and vacuum to remove dust and lint. For heavy buildup, use a non‑corrosive coil cleaner following label directions.
• Verify exhaust (portable): Ensure the exhaust hose is properly connected, not leaking hot air back into the room, and vented outdoors with minimal bends.
• Check room size: Confirm the BTU rating of the Whynter unit is appropriate for the room size and heat load.
• Refrigerant diagnosis: If coils are clean, airflow is good, and the air from the outlet is not at least 10–15°F (6–8°C) cooler than intake after several minutes, the system may be low on refrigerant or the compressor may be weak. Contact a licensed HVAC technician to check pressures, locate leaks, and recharge or replace the compressor as needed.