Question: What do the terms 'suction mode' and 'suction lift' refer to?


The term "suction mode" refers to a suction state with negative inlet pressure at which the pumped medium is supplied from a point located below the pump's suction port and which is in contact with the atmosphere (open system). This means that the pressure applied at the pump's suction port is less than or equal to atmospheric pressure. Centrifugal pumps always require sufficient inlet pressure in order to ensure that pump output is in accordance with the performance curve.

The available NPSH is crucial to proper operation. This is a system parameter that must be greater than the pump's required NPSH value plus a safety margin of at least 0.5 m:

NPSHA > NPSHR + 0.5 m safety margin

Additional information:

Enhance your knowledge

Find out how to get reduced energy consumption, increased comfort and unsurpassed operational reliability for your application. Read our customers' stories about how they benefit from the Grundfos approach to intelligence, water and energy, or search Grundfos research & insights for more learning materials, articles, white papers, videos and much more that benefit your solution.