Positive or Negative Pressure

[Coleus]

Hi to engineer or controller out there that can help me with my question about the air switch above my hood range. What happened was i unplugged my air switch to install the new hood range but forgot to mark if i connect the air probe to positive or negative pressure of the unit.

This is link to manual http://www.emersonclimate.com/Docume.../0037-4898.pdf


From reading manual, i think i should connect to negative pressure but if it sits in front of blowing fan, should it be positive pressure. This hurts my brain

Thanks