This problem is not what it might seem at first glance. While it is true that the water supply block may not be at the end of a pipe, it is more likely that the riser nipples somewhere in the grid (it is usually seen in a grid) are set to User Specified when they should be set to Computer Generated.
Elevating the system to 3D resulted in the following piping configuration:
Something is obviously wrong, here.
The grid that had this problem had branch lines that run with the slope of the building. Both mains were tied into the branch lines with User Specified riser nipples. The problem with doing that is that is it extremely difficult to calculate the exact length that the riser nipples will be to meet the differing elevations. The solution is to make the riser nipples on one side of the grid Computer Generated. The quickest way to change these is to use the Edit Riser Nipple command on the Riser Nipple flyout of the Piping toolbar. Or type in ERN.
Pick the first button – Change to Comp Gen/User Spec. Then Pick Computer Generated and pick Apply.
Select the riser nipples to change. You will see a magenta circle around the selected riser nipples. This tells you that those riser nipples will have their length Computer Generated.
The H-Factor 
Leave a comment