York air conditioner runs but does not cool well; supply air only slightly cooler than room

Safety: Turn off power before cleaning coils or opening panels. Refrigerant work must be done by a licensed technician.

• Check filters and vents: Replace dirty filters and open all supply and return registers.
• Clean coils: Clean the outdoor condenser coil and inspect the indoor evaporator coil for dirt. Clean with appropriate coil cleaner.
• Measure temperature drop: With system running, measure return vs. supply air temperature. A typical York system should have about 16–22°F (9–12°C) drop under normal conditions.
• Call a technician for charge check: If airflow is good but cooling is weak, a tech should check superheat/subcooling and correct refrigerant charge after repairing any leaks.