Portable Arctic King air conditioner displays F0 and stops cooling; fan may continue to run.

Safety: Unplug the unit. Refrigerant systems are sealed; do not attempt to cut lines or add refrigerant without proper EPA certification.

Steps to respond to F0:

• Clean condenser and filter: Remove and clean the air filter. Access the rear or side condenser coil and gently clean dust and lint from the fins.
• Check exhaust (portable units): Ensure the exhaust hose is properly connected, not kinked, and the window kit is sealed. Poor exhaust can cause high pressures and trigger F0.
• Restart after cooling: Allow the unit to sit unplugged for 30 minutes, then restart. If F0 returns quickly, a refrigerant or sensor issue is likely.
• Professional diagnosis: F0 often indicates a refrigerant-side problem. A licensed HVAC technician should check system pressures, inspect for leaks, and test the pressure sensor. They may need to repair leaks, evacuate, and recharge the system or replace the main control board if the sensor circuit is faulty.