How You know you have negative or positive pressure.

[Sage Connel]

I can say I know I have negative pressure. I unplugged one fan while the rest were spinning, and it slowed down then reversed direction as the air came down through it and was being pulled out by the other fans.

 

[Gam3r01]

Just for future advice, dont move/remove any connections while the power is on.
As for the pressure the easiest way to know is just to count intake v exhaust. More intake, more positive and so on.

 

[i7Baby]

Or use a Static Pressure gauge

 

[thespaceduck]

If anyone in your proiximity smokes just ask them to blow a bit of smoke in the direction of the fans. Just make sure you dont get too much smoke in there 😀

 

[Sage Connel]

yeah I know it wasn't the smartest.....but I still thought it was cool xD