A Caution message in AFT Fathom

Full message is:

"Pump X has no efficiency curve or nominal efficiency data. An efficiency of 80% was assumed in viscosity correction calculations."

This message displays for centrifugal pumps which use viscosity corrections to the performance curves. Typical corrections depend on efficiency data which typically depends on flowrate. No such data was provided by the user. Further, the user did not provide nominal efficiency either. In order to perform the viscosity correction an efficiency of 80% was assumed. Viscosity correction results are less certain in this case.