Flow rate is not transferring from pipe to pipe

[RJK42]

I am currently designing a hydronic cooling and heating system.  I created a family similar to the FCU family that is included in Revit.  I added some extra connectors and shared "Flow" parameter so that when I connect pipe to it, Revit will add GPM's Associated with the units and pipe, so that I can size my pump accordingly.  The problem that I am having is that as I give a GPM value to either a family or fitting,  I should see the sum of the GPM as I'm connecting it to my pipe runs.  I am not seeing this.  I though that Revit will add my GPM's for me.  I am working in a model that was created using the Architectural template.  That model is set as the central model, and I collaborate my mechanical discipline to it.  I thought that there may be some missing parameters on the MEP side so I open a new project from a mechanical and system template and transfer those parameters into the original Architectural model.  Nothing seems to work.

Thanks

[dtiemeyer]

It has been my experience that the calculations only work when there is one open end. Perhaps you are drawing in such a way that there are many possible 'routes' for the fluid to take, which will result in a 0 for any calculations. This is how it works with the plumbing piping anyways.

[RJK42]

--That makes sense--

I haven't connected it to the chiller yet.  I am working from the longes run so I can get my total head lost.  So when I get through hooking all my valances to the chilled water line and then completeing the loop to the chiller, it may give me my values I'm looking for??

I will keep you posted.

Thanks!!