Ac start up. Checked wiring from furnace to condenser unit. Found communicating wire not hooked up indoor and outdoor. Hooked up. Hooked up gauges and checked pressures and temps. Found 400psig of nitrogen on system. Dropped nitrogen from system. Hooked up and pulled a vacuum. Dropped to under 300 microns. Dropped charge. Cycled system. Checked pressures and temps. Found system low on charge. Added 8oz of refrigerant. Subcooling and split good. System operating normal at this time. Job complete.