Performed preventative maintenance for air conditioning system. Replaced the standard air filter (18x20x1). Inspected all the electrical components. Confirmed proper high and low voltages. Tested the gravity drain that goes from the attic to the ground level. Drain is clear of restrictions and working properly. Tested the temperature split between the supply and return. System is operating at a 20° differential on a 60° day. Tested the amp draw for the blower, compressor and fan motor. All are operating within manufacturers spec. System is operating properly at this time and is ready for the summer season. No charge due to free with install maintenance.