Today I conducted the annual preventative maintenance service on a Lennox Elite Series central air conditioning system. I began by thoroughly cleaning the outdoor condenser unit, removing any debris and ensuring proper airflow around the coil. I then checked the refrigerant charge, adding 6 ounces of R-410A to bring it up to the manufacturer's specification. Next, I replaced the 1-inch MERV 8 air filter and inspected the blower assembly. Finally, I cycled the system through all modes to verify efficient cooling operation and airflow balance throughout the home. The AC is now prepared for the summer season.