Which of the following is NOT a possible cause of a centrifugal pump not delivering enough liquid?

A centrifugal pump relies on specific conditions to function effectively and deliver an adequate amount of liquid. While high suction head can indeed negatively impact pump performance, it is essential to understand the various factors contributing to inadequate liquid delivery.

Worn wearing rings can create excess clearance between the impeller and the casing, which leads to a reduction in efficiency and loss of pressure, impairing the pump's ability to deliver sufficient flow. Additionally, a damaged impeller disrupts the movement of fluid, causing inefficiencies and potentially resulting in lower flow rates.

An undersized foot valve can also limit liquid delivery by restricting the volume of fluid that can enter the pump, creating air pockets or cavitation, further impeding the pumping process.

In contrast, while a high suction head might present challenges, it isn't a direct cause of insufficient liquid delivery like the other options listed. It's important to remember that many centrifugal pumps are designed to handle certain elevations as long as they are within the specified operational limits. Therefore, high suction head does not inherently prevent a centrifugal pump from operating effectively in the same way that physical damage or design limitations from the other factors can.