Low Refrigerant from a Leak
Low refrigerant fujitsu ac is the most common cause of a fujitsu ac running but not cooling fault after mode and filter issues are ruled out. When a leak reduces the refrigerant charge, the evaporator coil cannot absorb enough heat from the room air to produce meaningful cooling. The fujitsu ac blowing warm air symptom develops gradually as the charge drops, then becomes complete once the pressure falls below the minimum operating threshold. Low refrigerant always indicates a leak that must be found and repaired before recharging.
Requires a technician