For this super tune-up I inspected two air handlers and two condensers. Newer system which is for the upstairs was running well, however the downstairs unit I did not achieve a 20° Delta which indicated low refrigerant because the filter was new and the blower was running. When I gauged up the downstairs unit had a saturation temp of below freezing. I leak searched the evaporator coil and found a leak on one of the loops. I inform the customer and he is thinking about replacing and will be awaiting a call from a comfort advisor. The upstairs unit was running well however the capacitor is getting low however is still technically within tolerance.