Main duct take not the quantity of air of Air Terminals

[marco.defina]

Hello,

i connected a Air Terminal with two flexible ducts, why the main duct take not the quantity of air?

[Keith.Brown]

I believe that AutoCAD MEP will not automatically fill in flow values without first analyzing your system and sizing your ductwork.

Duct System Size Calculator

[Keith.Brown]

I was 100% wrong in my last post.

I created two air terminals and a main run of duct.  I then assigned 250 cfm to each terminal and connected them to the ductwork and the ductwork was assigned a flow of 500 cfm.

So I am not sure why you do not have flow assigned to your duct.

Does it have an endcap on one end and another piece of equipment on the other?

[Keith.Brown]

I was able to reproduce your issue and selecting the air terminals and opening and closing the equipment properties dialog fixed it for me.  This appears to recalculate the values for the ductwork.

[marco.defina]

Try my file...The problem is the two flexible, with one work fine. I think MEP cannot calculate the flowrate divided between 2 duct from one Air Terminal.

[Keith.Brown]

An easy way to tell would be to just delete one of the flex duct sections tap to tap and see. What I think probably is causing the issue is the circular nature of the route.

** EDIT **. I reread what you wrote and noticed that you already did this. Not sure of where to go from here unless you create dummy mvparts that you use to break your duct up so that it looks correct but functions so that there is only a single route for air to flow. A lot more work to use that method.

[marco.defina]

I tried to use a plenum with 2 connection IN and one connection OUT but didn't work...Loose the air flow...

For example 500 m3/h on the big connection, in the three little 0 m3/h