Hello,
I have problem with HVAC Systems in OpenStudio. In my model i created simple loop of water and air system but i can't make correctly simulation. I have errors like in the picture - "Sizing Zone". I tried to change software properties (simulation control), but it doesn't help. Thermal Zones, all properties of system element are OK (I think).
This system is only example. I didn't put there real values and elements. After correct simulation of this simple loop i will edit it according to my project.