I recently completed a job replacing an evaporator coil in a customer's home's heating and cooling system. The evaporator coil was defective, so I ordered a new one and installed it. I also recovered any refrigerant that was in the system, removed the old coil, and installed the new one. I nitrogen purged the line during the soldering process and pressure-tested the new joints. I evacuated the system and recharged it with new R410A refrigerant. I cleared any alarms on the thermostat and restarted the system. The system is now operating properly.