DIAGNOSIS The unit is running but not removing heat. The most likely cause is a refrigerant leak or the compressor has failed. Check for a P1 or E8 error code on the display first.
FIX First, verify the exhaust hose is connected correctly and vented outdoors. A blocked or kinked hose causes overheating. Next, check the air filter. Remove it, clean it with warm water, and let it dry completely before reinstalling. If the filter was dirty, run the unit again. If cooling does not resume, the issue is mechanical.
IF THAT DIDN'T WORK The unit may have lost refrigerant. Listen for the compressor attempting to start. A click followed by no hum indicates a failed compressor or a protection lockout from a previous overheat. Unplug the unit for 30 minutes to reset the internal thermal protector. Plug it back in and set to Cool at 60°F. If it still blows air only, professional service is required.
HEADS UP Portable AC units cannot be recharged with refrigerant by users. Attempting to do so will void the warranty and likely damage the system. The repair cost often approaches the price of a new unit.