Draft door opening?

[randomseeker]

I have an 18x60 Lapierre Junior. I read somewhere else in the forum that opening the draft door too wide may not be optimal. I leave mine open full. Can anybody suggest the science behind draft doors? Thanks.

[johnallin]

There's a fine line and depending on wood and other conditions, it changes often..open it too much, and you are introducing cold air into the fire box. Not enough and you may not get enough air for your fire. A lot of it depends on the draft you have in your system. On my Leader 2x6 with 16' of 12" stack - going straight up! - I keep it open about 1-1½" to start and then close up to 1/4" if we have good wood and a good boil going. Sometimes I crack it wide open if the wood's not the best or the boil is in need of a good kick in the pants. We also monitor stack temps, if they drop we crack it open a bit.

[Ausable]

John already answered the question. Remember the Fire Triangle? Heat, Fuel and Oxygen. For the event called Fire - these three things have to be in place. We can help them as we do in say - an Electric Generating Plant Boiler. The Fuel is Ground or atomized - preheated - and blown into the boiler ready to combust aided by hot combustion air. At the start - combustion is aided with spark gas igniters and possibly fuel oil torches if using pulverized coal. Once up to temperature the fire can sustain itself. My point is - everything possible is done to make an efficient fire. We - on the other hand - do what we can - as cheaply as we can. Actually - We do pretty good with what we have. I play with my draft door too. Kinda fun.

[Super Sapper]

Even with a fully open draft door there will be less air than using AUF so I would think leaving it open is your best bet.

[11-Nick]

Even with a fully open draft door there will be less air than using AUF so I would think leaving it open is your best bet.
I was thinking this, too. Using a fan to blow air into the firebox vs leaving the draft open.... can anyone explain the difference?

[Sugarmaker]

Most folks boil as fast as the rig will run. Good natural draft will boil right along. Your doing good!
Regards,
Chris

[wnybassman]

My 18x60 Lapierre has a blower mounted below the grates on the back side, and far out performs anything I do with the draft door with the fan off.

[WESTMAPLES]

im with wnybassman, when i added a blower to my 2x6 what a difference i made my AUF like the wood saver units in bascoms catalog i used a small pressure fan and 3 in grain auger pipe, welded it up, capped the pipe ends, took the plasma cutter and made 1 in long x 1/4 inch wide opens pointing up toward the bottom of the grates boy what a difference with a flip of the switch, before it was play with the draft door and get nothing else done between firings and yes the blower gave me a hotter fire and help reduce the wasting of wood from over firing to keep it rolling