No Loss Defined

[wsjsxn]

Hello,

I try to use the sizing function to size the ductworks. The duct has the certain CFM in the element properties. However, when I chose to use friction, I got the error message "NO LOSS DEFINED". DOES ANYONE KNOW HOW TO FIX THIS PROBLEM?

thanks

Shaojie

[KyleB_Autodesk]

Shaojie,
That method requires the determination of pressure drops along the connected duct networks. That cannot be determined if there is a fitting that does not know it's pressure drop.

Try using the System Inspector to determine the fitting that does not have a pressure drop defined.

Hope that Helps,
Kyle B
Revit MEP Product Manager
http://inside-the-system.typepad.com/