Ive been doing a lot of searching lately and i think i have figured out the basic concept of what i aim to do to get more efficency and heat out of my addon furnace ,it is th englander 28-3500 .First let me say I love the furnace lots of heat burns nice for us good economical choice ,but i have since got a englander nc13 for my shop and i am realizing theres lots of advantages on it .id like to apply that new secondary burn technology to my furnace to improve burn times and reduce my wood consumption .I have heard reports of people who have seen 15-25% less wood use by adding these on various non epa models .that could mean 1-2 cords less sawing splitting stacking etc..trust me I have reservations of cutting a hole in the back of my new air tight stove but as an experianced tool and die maker for the last 13+ years and my tinkering ocd i cant help but have these insane thoughts roam in my head .my plan is to use black pipe mainly 3/4 inner diameter ,I know stainless is better for heat transfer but im on a budget and i feel that changing 30$ worth of steel pipe every few years wont be a big deal .the stove is already pretty well setup so my idea is to run the tubes dow nthe angled baffle support rails and make a square loop at the baffle edge approx 14 inch wide and 25 inch long and have it tee into one pipe in back of the stove and out the back using washer and nut principle and on bot hsides to tighten and the use of chimeny cement .i plan to use staggered size and locations for the exit holes ranging from.125-187 in diameter approx 1 inch apart and pitched toward the center of the firebox,if routed right and from what ive seen others do this should give me enough freeair space to heat before it exits the holes int ofirey flames ..my first plan was to cut another hole i nthe air jacket sheet metal and run it through and out the back maybe 6 inches leading to a gate valve for adjustment ,then i read most people have them wide open anyways and if a chimney fire broke out i think the extingusher in the box would kill the secondary gassifcation immediatly anyhow .so i get the idea to angle the exit pipe 90 out the firebox in to the jacket and seal it back up wit hscrews this way it can get a good jump on heating the air due ot the air jacket being 50 degrees hotter than outside air and the advantage of the blower will push a draft into it onyl when the box temps are at 190 degrees and it will kick off once it cools which will stop the secondaries air over the coals resulting in better burntimes i think using the furnace's existing blower setup would be an advantage for this.any opinions guys ?
