🔍 Key Concepts
• Centrifugal pump performance when the discharge valve is throttled or closed
• Difference between mechanical issues (coupling, speed) and hydraulic performance issues (head/pressure, flow)
• How system symptoms (overheating equipment) relate back to the pump’s actual condition
💭 Think About
• Which choice directly tells you something about the internal hydraulic condition of the pump itself (impeller, clearances, wear ring), rather than something external in the system?
• When you close a centrifugal pump’s discharge valve, what should normally happen to the discharge pressure/head, and what would it mean if that expected change does NOT occur?
• Which symptom could be caused by several different system problems (fouling, low seawater temperature, scaling), and which one is a more direct diagnostic test of the pump’s own performance?
✅ Before You Answer
• Identify which option is a direct test of pump head vs. flow (a standard way to judge centrifugal pump health).
• Separate maintenance nuisance issues (like coupling attention) from true indicators of internal pump wear or damage.
• Ask yourself: if I saw this single symptom during watchstanding, which one would most strongly point to required overhaul of the pump itself, not just system troubleshooting?