Performed a 3 system spring maintenance ( gas). Tasks performed. 1. Visually inspected condenser coil for debris/ dirty. 2. Inspected condenser fan motors. 3. Inspected condenser fan blades. 4. Inspected/ cleaned wiring connections. 5. Tested compressor/ condenser fan motor capacitor. 6. Checked refrigerant pressure,,, downstairs unit is frozen ,,we need to come back and check again, issue might be caused by extremely dirty filter or low on refrigerant. 7. Checked compressors amp draw. 8. Checked condenser fan motors amp draw. 9. Inspected / replaced return filters,,, all 3 systems had extremely dirty filter . 10. Inspected return plenums for debris/ dirty,,,upstairs/ downstairs units are very dusty, highly recommend a duct cleaning. 11. Inspected evaporator coils. 12. Inspected blower motor/ blower wheels,,, downstairs/ upstairs are very dusty, highly recommend a blower cleaning. 13. Checked blower amp draw. 14. Measured temperature differential ,, temperature differential on the ups