When selecting a centrifugal pump for bypass work, the first consideration should be NPSHR by the pump. Neglecting the NPSHR of the pump is the single most common mistake when choosing a self-priming or priming assisted pump. A function of the pump design requires part of the 33.9 ft (14.7 in.) available as further defined in this article.
A centrifugal, and in a way submersibles, require part of the “Net Positive Suction Head Available” — NPSHA. The work that can be done therefore, on the suction side of the pump is limited, so NPSH becomes important to the successful operation of the bypass pump operation.
Submersible pumps have their place in bypass work; they commonly come electrically driven, but some are hydraulically driven with a power
pack that can be either diesel or motor driven.