Perform scheduled preventive maintenance on a wide range of HVAC and mechanical systems, including air handling units (AHUs), rooftop units (RTUs), variable air volume (VAV) systems, fan coil units (FCUs), exhaust systems, chillers, cooling towers, boilers, pumps and hydronic systems, heat exchangers, and HVAC systems supporting medical facilities. Work with building automation systems (BAS), troubleshooting control devices and field components, verifying sensor calibration and system performance, coordinating with OEM-certified personnel for advanced repairs, and supporting HVAC commissioning and recommissioning activities.