I am trying to place a pipe starting at a sprinkler head and then continuing downward. But with ACS Plane Snap disabled and regardless of how I set the orientation of the Accudraw compass, I can only go sideways.
The reason for this behavior is that the Apply Slope option is enabled in the ribbon bar:
As outlined in the Help, this option places pipe at an angle relative to horizontal dependent on the Method, Value and Direction defined. If you disable Apply Slope you should be able to route the pipe downward from the sprinkler head as desired.