Question 190General Subjects - 1st Asst/Chief

The correct answer is A) The shaft o-ring was not installed. The mechanical seal on a centrifugal pump is a critical component that prevents water from leaking out of the pump casing. If the shaft o-ring that seals the mechanical seal was not properly installed during the reassembly, it would allow water to leak from the seal area, as observed during testing. The other options are incorrect because: B) Starting the pump with the discharge valve closed would not cause leakage from the mechanical seal, C) starting with the suction valve closed would not affect the mechanical seal, and D) air binding would not directly lead to a mechanical seal leak.