A Caution message in AFT Fathom

This caution alerts you to a possible inconsistency in your input. When this warning occurs, you have defined a pipe with a length that is shorter than the elevation change between its connecting junctions. This may be an input error or a result of a junction which itself has an elevation change. If it is due to the junction having an elevation change, you can use different inlet and outlet elevations at the junction to resolve this.

If the issue is not resolved error may occur in the head/pressure drop calculations.