Conducted a full preventative maintenance service on a Ruud RA1630AJ2 3-ton air conditioning system for our client in Scotch Plains. Used a Fieldpiece SDMN6 Manifold to check refrigerant charge via subcooling method. Noted a 4°F subcooling delta, so removed 6oz of R-410A refrigerant. Flushed condenser coil with Nu-Calgon CalClean and straightened bent fins. Replaced air filters and lubricated fan motors. Cycled unit through heating and cooling modes, documenting operating pressures and temperatures. System operating within Ruud specifications upon departure.