If you select or troubleshoot a centrifugal pump on a water curve and then run it on a viscous liquid, you can miss duty, trip the motor, and create avoidable downtime.
60-Second Summary (For Maintenance & Operations)
Water curves are not "wrong"; they are just not your fluid.
Viscosity typically reduces flow/head, collapses efficiency, and can push absorbed power into overload.
The only defensible way to predict performance (within limits) is to correct the water curve using ANSI/HI 9.6.7, point-by-point...
