Practice Test GeeksCPM - Certified Plant Mechanic Practice Test
← All CPM Flashcard Decks

Plant Equipment Maintenance & Troubleshooting Flashcards

7 cards from real CPM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Plant Equipment Maintenance & Troubleshooting flashcards as text

  1. A centrifugal pump makes a crackling, gravel-like noise and its discharge pressure fluctuates. What is the most likely cause?

    Answer: Cavitation from insufficient NPSH available

    Cavitation occurs when vapor bubbles form and collapse because NPSH available falls below NPSH required, producing gravel-like noise and unstable pressure.

  2. Which action would most directly increase NPSH available to a centrifugal pump?

    Answer: Raising the liquid level in the suction tank

    Raising the suction liquid level increases static head on the suction side, which increases NPSH available.

  3. A new mechanical seal leaks steadily right after installation. Which is the most likely cause?

    Answer: Seal faces were damaged or contaminated during installation

    Immediate leakage on a new mechanical seal usually means chipped, scratched, or dirty faces, or a damaged O-ring from installation.

  4. Why should packing on a centrifugal pump be allowed to leak slightly during operation?

    Answer: To lubricate and cool the packing and shaft sleeve

    A small controlled leakage lubricates and cools the packing, preventing it from burning and scoring the shaft sleeve.

  5. A centrifugal pump runs but delivers no flow after a rebuild. Which should be checked first?

    Answer: Whether the pump is primed and rotating in the correct direction

    Loss of prime and reversed rotation are the most common reasons a rebuilt centrifugal pump produces no flow.

  6. Operating a centrifugal pump for extended periods against a closed discharge valve will most likely cause what?

    Answer: Overheating of the liquid in the casing and possible seal damage

    At shutoff, nearly all input energy becomes heat in the trapped liquid, which can flash, damage seals, and overload bearings radially.

  7. On a positive displacement pump, what is the primary purpose of a relief valve on the discharge side?

    Answer: To protect the pump and piping from overpressure if discharge is blocked

    Positive displacement pumps keep delivering flow against a closed outlet, so a relief valve prevents dangerous pressure buildup.