I completed the scheduled maintenance agreement cooling tune up on a Five Star 19 SEER 4 Ton Variable Speed Air Conditioner. I visually inspected the unit. Checked voltages, amps and pressures. I inspected the evaporator coil. I checked the temperature difference across the coil. Inspected heat pump. Checked refrigerant charge, voltages and amps. I rinsed the condenser coils with water. Cycled and monitored system. All operating normally at this time.