I've got an air loop with an outside air system that has no economizer, for which I've set the minimum flow to be 3000 CFM. The sum of my zones Design Specification Outside Air objects is 500 CFM. My fan is hardsized to 12000 CFM.
I've got AirTerminal:SingleDuctVAVNoReheat terminals serving my zones.
I ran the simulation for one week, and I had a lot of unmet hours. Upon investigation I was surprised to see that the actual Air System Outdoor Air Flow Fraction was always 1, while the Air System Outdoor Air Minimum Flow Fraction is 0.25 (and the zones don't matter like I explained above).
I then noticed looking at the Loop Supply Outlet Mass Flow rate, that the actual amount of air going to the zones was 1300 CFM, which is less than the Minimum OA Flow rate I specified!
How is this possible? And how can I force the system to deliver at least the min OA?
Is this related to the "Control for outdoor air" option I see in the GUI when I click on the air terminal unit?
