Pump & Fluid Handling Troubleshooting

Pumps and compressors are usually blamed for problems that are not theirs. A pump that loses flow is often responding to a suction-side change. A compressor that trips on temperature is often doing so because an intercooler is fouled, not because the compressor is sick. Read the system, then the machine.

The NPSH conversation

If a centrifugal pump is cavitating, you will hear it (gravel in the volute), see it (vibration rising), and measure it (amps bouncing, flow inconsistent). The fix is almost never in the pump. It is in the suction line. Low level in the tank. A clogged strainer. A partially-closed valve someone forgot to open after a PM. Temperature climbing and pushing vapor pressure up. The NPSH-available has to exceed the NPSH-required at the pump inlet. Everything else is downstream of that math.

Seal failures tell you what the process did

Mechanical seals do not fail for no reason. They fail because something upset the environment they were chosen for. Dry-run. Contamination. Thermal shock. Process fluid that changed composition. Before you replace the seal, figure out what changed. Otherwise the new seal will fail the same way.

Compressor fault patterns

Reciprocating, rotary screw, and centrifugal compressors each have their own tells.

Reciprocating: valve issues dominate. Broken reeds, sticky plates, contaminated oil emulsion in the crankcase.
Rotary screw: oil carryover and separator element saturation. Unloader valves that stop loading.
Centrifugal: surge. Anti-surge controls that are no longer well-tuned for a new operating point.
All of them: intercooler fouling makes them run hot and draw amps. Clean the intercoolers on a schedule.

Safety the usual reminders skip

Never stand in front of a pump discharge on first start-up. Trapped air can eject bolts at lethal velocity. On compressed air receivers, 150 psi in a 1000-gallon tank holds enough energy to level a building if it ruptures. Relieve pressure before breaking any flange, and verify zero at the point of work.

2 machines covered in this category

Goulds Pumps

3196

ANSI Process Pump (ITT Goulds)

7 guides

Atlas Copco

GA VSD+

Variable-speed rotary screw air compressor

8 guides

Related learning

Deeper explainers and background reading for technicians working in fluid handling.

Pump Failure: 8 Common Causes and How to Prevent Them

Pumps fail for predictable reasons: cavitation, dry running, seal wear, misalignment, and a handful of others. Once you know the eight patterns, you can set up monitoring and PM tasks that catch each one early. This guide covers every common failure mode with prevention steps.

Vibration Analysis Basics: What Your Equipment is Telling You

Every rotating machine vibrates. The pattern of that vibration tells you whether bearings are wearing, shafts are misaligned, or components are out of balance. Learning to read vibration data catches 90% of rotating equipment failures weeks before they happen.

Compressed Air Leak Detection: Save 20-30% on Energy Costs

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Shaft Alignment Fundamentals: Precision That Prevents Failure

Misalignment is the second leading cause of rotating equipment failure after lubrication problems. Laser alignment takes 30 minutes and prevents months of accelerated wear on bearings, seals, and couplings. This guide covers the basics of angular and offset misalignment correction.

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