Holmes Intake/Exhaust Dual Fan - House/Shop/Paint Booth

It is the timer/comfort control knob. All the way to right fan runs continuously.
To set run fan until your desired area temp is reached. Turn dial to left, until fan shuts off. Fan will then turn on & off automatically to maintain that temp.
Here is manual.
https://www.holmesproducts.com/on/d...ruction-manuals/HAWF2041_15EM1 Window Fan.pdf