HVAC 3 builds on prior coursework and includes modules on Fasteners, Hardware, and Wiring Terminations, Troubleshooting (Control Circuit and Motors, Cooling, Heat Pumps, Gas Heating, Oil Heating, Accessories), Zoning, Ductless and Variable Refrigerant Flow Systems, Commercial Hydronic Systems, Steam Systems, Retail Refrigeration Systems, and Customer Relations. HVAC 3 is part of a comprehensive four-level HVAC curriculum that complies with DOLI standards for apprenticeship and is recognized by North American Technician Excellence (NATE).