An HVAC technician installs, maintains, and repairs heating, ventilation, air conditioning, and refrigeration (HVACR) systems in residential, commercial, and industrial settings. Key responsibilities include inspecting equipment, diagnosing malfunctions, performing preventative maintenance like cleaning and lubricating, repairing or replacing parts, installing new units according to blueprints, and ensuring systems comply with safety standards and building codes. Technicians also communicate with clients to explain issues and provide maintenance tips, and they maintain accurate records of their work.