Question 111Steam Plants - Assistant Engineer

The correct answer is D) discharge piping temperature. A leaky fuel oil heater relief valve would cause an increase in the discharge piping temperature. This is because the leaky valve would allow hot fuel oil to bypass the normal heating process and enter the discharge piping, leading to a rise in temperature. The other answer choices are incorrect because they would not be directly affected by a leaky fuel oil heater relief valve. Increases in contaminated drain tank level, fuel oil service pump pressure, or sludge tank level could be caused by other issues, but would not be the primary indication of a leaky relief valve.