Performed AC cooling tune ups on 3 AC systems checking all electrical components, refrigerant balance unit start up, operation, shutdown, cleaning of indoor and outdoor coils, and treatment of drains. Everything looks and runs great! All 3 systems were installed at the same time around 1999 and all 3 systems use R-22 refrigerant that was phased out in 2016, any issues with the refrigerant system could potentially cause end of life for any of the systems, at this time the refrigerant balance on all systems is within manufacturer's specifications and system is not showing any signs of failure.