Field Service Field Service Technician Field Engineer Service Tech Landfill Vapor Flares Boilers Electrical Mechanical Maintenance Turbines Water Treatment Oil and Gas Refining Refinery Troubleshooting I/E I&E Instrumentation Instruments Calibration Aerospace . This equipment includes, but is not limited to pumps, motors, variable frequency drives (VFD), positioners, valves, actuators, transmitters, combustion equipment, emissions monitoring equipment, digital recorders, and Programmable Logic Controllers (PLC).