🔍 Key Concepts

• Fuel oil service system booster pump operation and purpose • How a duplex suction strainer works and why it has two baskets/elements • Meaning of pressure differential (pressure drop) across a filter/strainer as it becomes dirty or clogged

💭 Think About

• Think about what happens to flow resistance as the strainer gets more and more clogged: does it get easier or harder for fuel to pass? • If resistance increases in the strainer, how will the inlet and outlet pressures of the strainer compare to each other? • Which of the listed indications would most directly tell you about the cleanliness of the strainer element itself, rather than a change in pump performance?

✅ Before You Answer

• Identify which answer choices refer specifically to pressure drop (differential pressure) across the strainer, not just pump behavior • Recall whether a clogged strainer causes more or less differential pressure between inlet and outlet • Verify which indication you would actually monitor on the strainer body on a real system (e.g., differential pressure gauge or two pressure gauges).