Responsibilities for a Hearth Technician include assisting with installations, venting, appliance start-ups, troubleshooting, and maintaining safe, clean job sites while learning manufacturer specifications, NFI standards, and local codes. In order to enjoy this work, you need to be comfortable working at heights, be able to lift 50+ lbs. A NFI certification allows a Hearth Technician apprentice or trainee to advance to becoming a Certified Hearth Technician.