HVAC and Refrigeration Systems: Advanced troubleshooting of RTUs, air handlers, exhaust systems, economizers, dampers, compressors, condenser and evaporator fans, chilled or conditioned spaces, airflow problems, controls, contactors, motors, belts, sheaves, coils, drain systems, and temperature control issues. Measuring and Calibration: Advanced use of multimeters, clamp meters, megohmmeters where authorized, tachometers, infrared thermometers, pressure and vacuum gauges, micrometers, calipers, dial indicators, laser or precision alignment tools, torque tools, and layout equipment.