I have Revit 2016 & Revit 2017. In the 2016 version I can create a plumbing system and when I click on it, and look in the "System properties" it would tell me the flow rate and pressure drop in the system without having to produce a "pressure drop report" However in revit 2017 when I click the "system properties" it says the flow rate is "0.000l/s" and the pressure is "0 Pa" however if I produce a "pressure drop report" it will give me an actual flow rate and pressure drop.

Does anybody know why my calcs in the properties aren't "updating" thanks.