Which outcome arises when a multi-stage centrifugal pump experiences excessive clearance between its impeller and diffuser rings?

💡 Explanation

When clearance increases, fluid recirculation occurs because higher pressure fluid leaks back into the lower pressure stages, reducing net pressure increase and decreasing the pump head. Therefore, reduced pump head results, rather than motor overload, overheating, or bearing damage which don't arise primarily from internal recirculation.

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