Troubleshooting is a systematic approach to identifying and resolving engineering problems. These guides provide step-by-step diagnostic procedures for common equipment failures, process upsets, and system malfunctions across engineering disciplines.

## Electrical Troubleshooting **Motor won't start:** Check power supply voltage (measure L1-L2-L3), verify control circuit fuse/breaker, test motor winding resistance (insulation resistance > 1MΩ), check thermal overload settings, verify starter contactor operation. **Breaker trips repeatedly:** Identify trip type (overload vs short circuit vs ground fault), measure load current with clamp meter, check for harmonic content, verify breaker rating matches load, inspect for insulation degradation. **High motor temperature:** Measure running current (should not exceed FLA), verify cooling fan operation, check bearing condition, measure supply voltage balance (should be within 3%), check for overloading. ## Mechanical Troubleshooting **Pump vibration:** Measure vibration amplitude (ISO 10816), check bearing temperature, verify alignment (laser alignment to 0.002'), check impeller balance, verify foundation rigidity, check for cavitation noise. **Pump low flow:** Check suction strainer for blockage, verify NPSH available > required, check impeller clearance, measure discharge pressure, verify check valve operation, test pump speed. **Compressor high discharge temperature:** Check suction temperature and pressure, verify intercooler performance, check valve condition, measure oil temperature, verify cooling water flow. ## Piping Troubleshooting **Pipe vibration:** Identify frequency (VFD vs mechanical), check support spacing per code, verify pipe clamp condition, check for slug flow, measure stress at supports, consider acoustic pulsation analysis. **Flange leak:** Check bolt torque (tighten to mfr spec), verify gasket selection (material + thickness), measure flange face parallelism, check pipe support alignment, consider torque sequence. ## Process Troubleshooting **Control valve sticking:** Check actuator air supply (80-100 psi), verify positioner calibration, check stem packing adjustment, inspect for seat erosion, test I/P transducer output. **Flow measurement error:** Verify flow meter type matches process conditions, check upstream straight run (10D min), verify sensor calibration, check for gas/liquid in wrong phase, test signal cable integrity.