Which of the following would not cause a centrifugal pump to fail in delivering water?

Slight leakage of the packing in a centrifugal pump typically does not prevent the pump from delivering water effectively. While packing is intended to provide a seal and reduce leakage, a minor leak may not significantly impact the pump's performance, especially if the pump is otherwise functioning correctly and operating within its design parameters.

In contrast, air leaks in the suction line, clogged inlet strainers, and improperly sized impellers can lead to significant problems in maintaining proper water flow and pressure. Air leaks can introduce air into the system, disrupting the vacuum required for fluid to be drawn into the pump. Clogged inlet strainers can restrict water flow, leading to cavitation or reduced efficiency. Finally, an improperly sized impeller can affect the pump's ability to generate sufficient head, resulting in poor performance or complete failure to deliver water.