Question 522Steam Plants - Assistant Engineer

The correct answer is B) the gravity tank is overflowing. When oil is observed flowing through the sight glass in the line between the lube oil gravity tank and the main sump, it indicates that the gravity tank is overflowing. This is because the lube oil gravity tank is designed to provide a constant supply of oil to the main sump, and any excess oil will flow back to the sump through this line, which is what is observed in the sight glass. The other options are incorrect because: A) a stopped lube oil pump would not cause oil to flow through the sight glass, C) a clogged suction strainer would restrict oil flow, not cause it to overflow, and D) a full lube oil sump would not cause the gravity tank to overflow.