Troubleshoots and take necessary corrective action for major malfunctions and breakdowns of heating/refrigeration and air-conditioning systems, pumps, air heating/refrigeration and air conditioning units, coils, fans, subsystems and component parts, steam systems, etc. Exposed to any number of elements and may be required to work in conditions including cold, heat, temperature swings, noise, outdoors and indoors, in trenches, and around mechanical, electrical, explosive, fume/odor, dust/mites, chemical, and toxic waste hazards.