Question 268General Subjects - QMED

The correct answer is B) Replace the wearing rings. As a centrifugal pump ages, the clearance between the impeller and the pump casing (known as the wearing rings) increases, resulting in reduced pump efficiency and discharge pressure. Replacing the wearing rings will restore the proper clearance and improve the pump's performance. The other options are incorrect because: A) Throttling the discharge valve will only further restrict flow and reduce pressure, which is the opposite of the desired corrective action. C) Replacing the lantern rings, which are part of the mechanical seal, would not address the issue of increased clearance between the impeller and casing. D) Throttling the suction valve would also reduce flow and pressure, which is not the appropriate solution.