A Chiller Technician installs, maintains, and repairs large-scale HVAC and industrial refrigeration systems, ensuring efficient temperature control in buildings or factories by performing diagnostics, preventive maintenance (filter changes, lubrication), troubleshooting breakdowns, managing refrigerant levels, and ensuring compliance with safety standards, often working with building automation systems and requiring strong mechanical and electrical skills for air-cooled/water-cooled chillers, pumps, and cooling towers.