Display shows F0; unit may not cool properly or may shut down intermittently.

Safety warning: Refrigerant systems are sealed and under pressure. Do not attempt to cut or open refrigerant lines yourself.

User-level checks:

• Clean filters and coils: Dirty filters and coils can mimic low refrigerant symptoms. Clean the air filter, evaporator, and condenser coils thoroughly.
• Check for icing: Inspect the evaporator coil for ice buildup. Persistent icing after cleaning may indicate low refrigerant or airflow issues.
• Listen for compressor: Confirm the compressor runs when cooling is requested. If it cycles rapidly with F0, the system may be protecting against abnormal pressures.

Professional service required: If F0 persists after cleaning and ensuring good airflow, a licensed HVAC technician must check refrigerant pressures, locate leaks, and recharge the system if appropriate. They may also test and replace any pressure or temperature sensors associated with the protection circuit.