I'm wondering what the best size as far as a width and depth would be for creating my exhaust flue area on my oil tank evaporator I'm building now?
I put a 6-inch ledge 4 a preheater pan 9 in above the other level I'll include a picture to show what I'm talking about, so I'm wanting to put a rectangular exhaust out of the top of my oil tank so that the flame get spread out along more of the pan to create a more efficient boil as I've seen this in commercially made evaporators ( wondering what's best size to create this opening in top of my oil tank?)
I can go as wide as 24 in which is the width of My preheater Pan and as deep front to back on the evaporator length of the oil tank 3 in...
Thanks MattIMG_20180817_145326562.jpg