Performed AC Diagnostic on 2017 Lennox condensing unit. Client stated that house is in escrow right now inspector noticed that temperature split was not in the proper range. 1. System Was slightly low on R410a refrigerant charge 2. Charged approximately 3 pounds of refrigerant into the system and Home is now cooling with a 20° temperature split. 3. Recommend filters are swapped every one to three months 4. Recommend that system is maintenance at least twice a year during the winter and summer season. System was fully charged up and is cooling with 21 degree temp split upon departure.