050100150010203040506070pump headNPSH requiredsystem, valve open121 m3/h38 msystem, valve throttled97 m3/h47 mflow rate Q (m3/h)head (m)The operating point belongs to the system, not to the pumpefficiency (%)020406080100efficiency (right axis)BEPpump headNPSH requiredstatic liftsystem, valve opensystem, valve throttledefficiency (right axis)