According to my (limited) knowledge, and in absence of an answer by
the experts, phenomena causing air flow in COMIS include

- wind pressure (meteo data in global cards)
- temperature differences (zone/zone, zone/external)
- Thermal buoyancy (stack effect)
- mechanical ventilation (fans)

You can also make air flow by introducing coonstant pressure points
somewhere in the network (and thereby create a pressure difference).

If you have none of these defined, you should send us your project to
look at.

Werner

--- In comis@yahoogroups.com, "justindhy" <justindhy@...> wrote:
>
> Dear all,
> I was confused that there were still flow rate and pressure in
zones
> even if I set wind speed zero and no temperature difference between
> inside and outside. Could anyone explain the possible reasons?
>
> Best regards
>
> Justin
>