🔍 Key Concepts

• Fuel oil service system flow path from storage/settling tank → service pump → heaters/filters → engine • Purpose of a relief valve (protecting pumps/lines from overpressure by sending excess oil back somewhere safe) • Where in the system pressure is lower and safe to return excess fuel oil

💭 Think About

• When a relief valve opens, do you want the fuel to go to a high-pressure or a low-pressure part of the system? Why? • Think about what would happen to engine supply if the relief valve dumped oil all the way back to a tank far away versus somewhere very close in the circuit. • Which option provides a short, controlled path that keeps the pump protected without interrupting fuel supply to the engines?

✅ Before You Answer

• Confirm which option is on the low-pressure side of the service system circuit. • Eliminate choices that would unnecessarily lengthen the return path or create risk of aeration/temperature loss. • Check your mental diagram of the fuel system: storage/settling → service → filters/heaters → engines, and locate where a pump relief valve is normally piped.