Question 40Steam Plants - QMED

The correct answer is A. The gravity lube oil tank is designed to maintain a constant level of oil in the system. The item labeled "D" in the diagram would be used to verify that the gravity tank is full and overflowing, as it represents the overflow pipe that allows excess oil to return to the sump or drain tank. The other answer choices are incorrect - item "N" is likely the drain valve, and item "O" is likely the filling port. The gravity tank is not designed to normally overflow, so option D is also incorrect.