hi everyone. new to the board, first post.
ok, i've got an overhead hood and need to make this thing work. i'm using a big, old coal-fired forge. i've never used a hood before, just got everything installed and it's not drawing well, at all.
first off, dimensions... the hood is 4ft long x 3'3" wide (nearly exactly the same as the forge) and about 2'3" high, so it's fairly large. attached to it is an 8" duct w/blower. it's a straight shot through the ceiling. the entire duct is only about 3 feet long, sticking only 1.5 feet up out of the roof.
i'm in an outdoor smithy (lean-to by a barn) with the sides tarped off to limit ambient air. when i fired up the forge the smoke was blowing through the chimney at what seemed like a good rate (w/blower going) but the hood quickly filled with smoke and billowed out, into the shop.
my first thought is, the chimney's not tall enough.
my second thought is, where the duct is attached to the top of the hood, it sticks through, into the hood, a couple inches. (causing the smoke to swirl inside hood?)
my third thought is, the duct is fairly small (even with a blower).
any insight? i've read that side-draft hoods are recommended for a better draw but since i've got this one (and put time into it) i'd like to use it, if i can.
thanks a lot, in advance.
mo