Checked the operation of the A.C units.Cleared the condensate drain and trap. Checked and tightened the electrical connection. Took amp readings on the fan motors and compressor. Took a temperature split across the coils. Checked the filters and found them to be clean. Washed the condenser coils. Checked the refrigerant levels found the downstairs unit #2 low on refrigerant. Leak checked the system and did not find a leak at this time.charged the unit with R22 refrigerant