Troubleshoot and Repair: Diagnose and repair heating, cooling, and ventilation issues in residential HVAC systems, including furnaces, boilers, combi-boilers, air conditioners, heat pumps, and ductless systems. Maintenance and Service: Perform routine preventive maintenance (PM) tasks on residential HVAC systems, including cleaning coils, changing filters, checking refrigerant levels, inspecting electrical components, and ensuring all system parts are functioning optimally.