Adding AOF on Smoky Lake 2x6 Evaporator

Hello All,

I have been researching AOF all over this website and got great information! My evaporator is a Smoky Lake Corsair 2x6 drop flue. Currently it has factory AUF and burns HOT! Boil rates are around 55 GPH when running all out. The only thing is, it chews through wood. There is never any smoke that comes out of the chimney, just lots of hot embers.

I did lots of reading on how adding AOF can increase load times and keep the fire burning hot. I pretty much have all my parts selected regarding blowers and have a good game plan of how I’m going to bring the air tubes under the greats and up the front of the firebox.

My question is, do I need to protect the steel tubing that I am going to use from the heat of the firebox? I’ve read that people pour refractory cement over their steel tubing to protect it from heat and use nozzles to direct the air. My issue is I am already limited on space in the firebox since it is only a 2x6 evaporator and I only have enough room to fit the AOF manifold without protecting it.

Part of me is wondering if it is even worth doing AOF as the evaporator already burns HOT. I was just itching to see if I could somehow burn less wood.

I bought a used maple pro 2x6 raised flue a few years ago. I put my AOF manifolds on the outside of the arch, right under the pan rails. I can't seem to load photos, but if you message me I can email you some. I have 6 pipe nipples on each side of the fire box, angled down 10 degrees. I haven't measured air speed, but my firing time is between 8-12 min now vs 5 to 7 min. I'm burning soft maple. low btu wood and I'm getting 40-45 gph. Working on my preheater now, hopin to get her up to 50!!.

I'd been boiling on a home made arch with AUF a few years before getting this one, and like you said, it really ate a lot of wood. When I bought the MP, I put both AUF/AOF on it as soon as I got it home. The previous owner claimed 25 gph. He just laid fire brick in, no mortar, and had rebar for grates. I closed in the bottom, lined it with ceramic blanket, bottom and sides, and mortared the brick in. We welded up some 1 1/2" angle for grates VVVVVV style. I'm using a 650 cfm wood shop dust collector for a blower. It worked great when I had it right behind the evaporator. The year before last, I plumbed up abotu 40' of 3" schedule 40 pvc and moved the blower right outside the sugar house to cut down on the noise. I lost alot of air pressure due to the extra resistance. This year I'm bumping it up to a 1350 cfm blower. My arch front is the regular ol cast iron, I can fire without having to shut the blower down. She really roars. My pans are 20 ga, I guess that's where SL gets their improved boil rate with the thinner pans. Anyways i also split my wood a little bigger this summer. I experimented a little last year and the larger wood 3 1/2-4 1/4 diameter didn't slow the boil compared to the 2 1/2 -3" wood I'd been burning for several years.

I get a little long winded, but hopefully something you can use here. I read maple trader for four years before i finally got to move home and start tapping. Sure have learned a lot here. Here's one of the many threads I used for my project. Good luck!!http://mapletrader.com/community/sho...ht=windy+acres

Not a Smoky Lake, but I added AOF on my 2001 arch 3x8 after buying that one in about 2007 and using it for 1 season without AOF. I removed the bricks down to leave 6" below the pan to place the AOF manifold. Directions said to use a 3" mainline, I only used a 2x2 sq tube because I had lots of it. I placed a nozzle every 6" starting at one side of the fill door,all the way around to the other door, each angled about 12 degrees downward. I then feed the air from a 100+ yr old high pressure blower, converted from 3 phase to belt drive 120V AC. Never did test to get pressure but if performed great. My boil went from every 7 minutes to every 9, and my boil went from about 55 gph to 70+ gph, while my stack temp went from 1200-1500F to 800-950F (the heat was being used under the pans).
My wood use dropped about 60-70%.

Thanks for the feedback. I haven't even thought of routing the AOF Manifolds outside of the arch. That will definitely save me alot of space in the firebox. Even better is I won't have to cut my cast iron grates on the bottom to route the manifold through.

How far down below the pans should my nozzles be located?