Originally Posted by inspectorD
Look at the plaster pressed through the wire mesh
I guess it's against Code to use a plumbing vent pipe as a range hood vent pipe.
Why not run a vertical 3-1/4" duct between the studs, up or down, until you can go horizontally, with maybe a 24vac booster fan at the distant end?
If Broan won't help with this, ask them for the Fan Curve
for this hood blower and use the Engineering Toolbox to calc. the duct airflow resistance.