Installed a Daikin FIT air conditioning unit. On the installation day, removed the old equipment and air handler deck support. Fabricated an insulated return air plenum and installed it in the return air box. Installed the air handler, media filter, heater, float switch, hurricane pad, heat pump condenser, copper line set, surge protector/hi-lo line protector, and thermostat. Ran a new control wire from the condenser to the air handler. Purged the line set with nitrogen while brazing. Tested the joints and evacuated the system. Opened the isolation valves and programmed the thermostat. Once the thermostat was programmed, Started the system and checked its operation. The system was operating properly.