I completed a detailed maintenance check on a York HVAC system, model YCE48B21SA. The service involved deep cleaning of the evaporator and condenser coils to optimize thermal efficiency. I also checked and adjusted the refrigerant levels according to York's specifications to ensure maximum cooling capacity. The electrical connections and capacitors were thoroughly inspected for any potential issues. I replaced the existing air filters with new, high-performance filters to improve air quality. The unit's functionality was fully tested to confirm efficient operation.