Ac repair call. I arrived on-site to replace the evaporator coil for the upstairs system. I pumped the system down and removed the faulty evaporator coil and replaced it with a new aluminum coil. Brazed in a new unit and replaced filter dryer, pressure tested with nitrogen and pulled vacuum to <500 microns. I charged the system to manufacturer specs at 7degrees subcooling. The system is operating normally at this time. Replace evaporator coil under parts warranty.