Is it possible to have one way flow VC dampers?

[iggleton]

I am trying to model an underfloor air distribution system which has underfloor ducts, the flow rate to the underfloor air distributors is controlled by volume control dampers in every duct to determine the flow rate to each distributor in l/s. The air is returned at the ceiling, so it does not get recirculated into the underfloor ductwork. The current mixing damper set in IES seems to force the return air to be recirculated to the supply air unit. Is there a way around this?

[farahghanem]

The air that goes through the ceiling is being exhausted? or is it returned to the main supply?

It is not possible to have one way flow systems as that would create negative pressure in the network, so the air in the room needs to either be exhausted out or recirculated. You can determine the recirculation path by editing the prototype system (if that's what you're using).