Low Flow


Usually called minimum flow; it is a condition that can cause excessive heat inside the pump volute.

A temperature rise of 10°C (18°F) across the operating pump is considered excessive. High heat is often caused by:

  • Excessive clearance between the open impeller and volute or back plate depending upon how the impeller is adjusted. This clearance will cause the fluid to recirculate inside the pump.
  • Excessive wear-ring clearance if you are using closed impellers.
  • Throttling a pump discharge valve because the pump was originally oversized as a result of safety factors that were introduced during the selection process.


  • On February 16, 2018