Provides primary response to tenant complaints regarding building automation systems (BAS), which includes HVAC, lighting, and fire alarm/suppression system; operates and interprets building automation systems; performs preventative maintenance; calibrates control components and makes repairs and replacements as needed. Inspects, maintains and performs preventative maintenance on all components of HVAC systems (e.g. changes, rebuilds and services semi-hermetic compressor, replaces piping, replaces rotating equipment component, replaces electric and steam humidifiers, repairs air compressors and related control, replaces belts, pulleys, motors, etc.); pumps down, may excavate and recharge refrigerant systems, calibrates electrical and pneumatic control components and makes repairs as needed; diagnoses malfunctions and repairs or replaces defective systems through modification overhaul if necessary; operates emergency backup equipment as required; performs various semi-skilled and skilled tasks (e.g., plumbing, carpentry, wiring, painting, plastering, glazing, welding, etc.). Operates and maintains domestic hot/cold water systems and water pressure booster system (e.g., semi instantaneous water heaters). Performs chemical treatment of boilers, chillers and closed/open loop piping systems. Performs preventative maintenance and repair to building boiler and chillers systems and support equipment; treats water with rust preventative; greases and oils equipment; checks and replaces release valves; repairs pumps, stoker, air compressors, motors, ductwork, piping, emergency backup system, etc. Maintains records of water usage, fuel consumed, steam, produced, gauge readings, and other related data as required. Demonstrates regular and predictable attendance. Performs other maintenance work as directed by supervisory personnel; serves as lead worker; works with contractors to solve and/or alleviate maintenance problems. Performs duties of co-workers as required or assigned.