Maintain and repair motors, fans, compressors, condensers, evaporators, actuators, piping, valves, electronic controls, make-up air units, ducting, dampers, boilers, chillers, cooling towers, water treatment system, pneumatic, electric and electronic controls, air handler units, make-up air units, fan coils and variable air volume boxes. Triangle Environmental is a 40-year-old open shop commercial HVAC and refrigeration service, repair, and maintenance contractor with a stellar stable of repeat customers.