Manometric suction lift
The manometric suction lift is the apparent suction lift indicated by the pressure gauge of a centrifugal pump . It is calculated from the geodetic suction height and the friction losses of the suction hoses .
When bleeding (suction) of the pump, the Eingangsmanometer showing venting means a negative input pressure ( relative pressure ). Multiplying this value in bar by –10 results in the manometric suction height in meters.
Example: If the inlet pressure gauge of the pump shows an inlet pressure of -0.4 bar, then this corresponds to a pressure height of 4 m.
source
Presentation of the state fire brigade schools of Lower Saxony