Secondary burn achieved on Hot Blast 1500

[TdiDave]

I had a some of the black iron fittings and nipples laying around but I did have to buy about $50 worth of stuff.
I have a total of 35 3/64" holes (10 down each edge pipe and 3 on each ladder pipe)
I fired it up tonight and to seem to get a lot of flames bouncing around the pipes and some occasional blow tourch from the holes. Any recomendationa on the direction the holes should face (strait down, forwar, rear word ?)
I don't have a strong suction on the 2 inlet pipes, should I? Is that a sign of not enuf holes?

 

[Bushmans]

Nothing man, nothing! So sorry, I'm way into this stuff, done some myself, I must have moused over "dislike" inadvertently! I dislike the dislike button! BTW, I fixed it.

No problem! I kinda figured that's what it was just wanted to make sure. On my tablet it is almost impossible to hit the right button. I've done it enough times myself.
They really should do away with it. Seems kinda like a cheap shot. You should have to back it up with real words! Heaven forbid there might be an argument on AS. LOL

 

[Bushmans]

Holes should point towards the flames (down and slightly in) is what I've read on other re-fabs. I've also heard that black pipe won't last very long but some use it to perfect the system before copying it to Stainless.
I was going to run my pre-heat along the bottom, up the front and then just under the baffle with holes drilled in the last section under the baffle. I would think your pre-heat on top of the baffle wouldn't get as hot as being in the main box where all the fire is. The hotter the air in the tube the better. Keep us posted! Burn times too?
I'm still under the impression that while secondaries burn better and cleaner it speeds up burn time.
Can't wait to get a first hand on a re-fab!

 

[brenndatomu]

I don't have a strong suction on the 2 inlet pipes, should I? Is that a sign of not enuf holes?

Any idea what your draft reading is? I have a tall chimney, so I have a baro to control the draft, once the secondaries were installed I had to reset the baro for a bit higher draft. Drilling larger holes will help though. Do you have a way of seeing the fire?

I'm still under the impression that while secondaries burn better and cleaner it speeds up burn time.

I didn't find that, especially if the primary air can be cut way back after the stove (furnace) is in "cruise" mode. That is why I think it would be hard to do this without being able to see the fire, because it makes it easy to see if the secondarys are running rich or lean and then adjust the primary or secondary air flow accordingly. It can make things "fiddly" until you figure out the new normal.

 

[laynes69]

The holes in my burn tubes point forward to the door. They run parallel to the baffle, where the last tube shoots in both directions. You don't want too much air, especially if you have a tall chimney. I would see how it works before modifying anything else. Like mentioned, the wood doesn't burn up as fast because of secondary combustion. As the primary closes, the secondary air will produce more pull. The majority of the fire will occur under the baffle, where the smoke is consumed. If I plug my secondary air ports, the fire will almost go out, the chimney will smoke and heat output will drop. There's a significant difference with secondary combustion. There's been a few people modify their furnaces just like that one, and they ended up more than impressed. I was going to do ours, before I bought our new furnace.

 

[TdiDave]

Draft is 0.05 a 0.06
I have the holes in the center pipes facing slightly forward now.
Only way I can see the fire is thru the slots in load door draft control. I am getting some nice blue flames covering most of the underside of the baffle, never had that before.
Flu temps 250, stove front holding about 400

Not sure why the pictures post upside down.

 

[brenndatomu]

Draft sounds perfect. NICE WORK!
If pics are from a phone, they will be upside down for some reason. Take them upside down they they will be right when posted

 

[Chris-PA]

Nice job!

 

[blades]

If you copy pics to a file then use an editor to rotate them and re-save problem solved, then up load from the new file.

 

[KindredSpiritzz]

I been pondering doing this to my Norseman 2500. Just can't bring myself to actually drill holes in my furnace. Gotta work up the courage for that i guess.
Be interesting to see how long those pipes hold up to the heat. Another popular mod seems to be putting another row of fire brick along the top of the existing ones in the fire box, held up by a length of angle iron.
After looking at your pipes you may be able to tuck yours in behind your pipe on top, looks liek there might be enough room there.

 

[TdiDave]

I been pondering doing this to my Norseman 2500. Just can't bring myself to actually drill holes in my furnace. Gotta work up the courage for that i guess.
Be interesting to see how long those pipes hold up to the heat. Another popular mod seems to be putting another row of fire brick along the top of the existing ones in the fire box, held up by a length of angle iron.
After looking at your pipes you may be able to tuck yours in behind your pipe on top, looks liek there might be enough room there.

Funny you mention that as I just picked up 12 more bricks to do that exact thing. They will fit just behind the pipes, I may not get all 6 in as the elbow at the from an back stick out a bit further and I don't think I can squeeze it in.
I pipe has been glowing red so time will tell how long it will hold up.
First over night burn seemed better as I awoke to 74 and still a good bed of coals, usually temp will drop into mid 60's by morning. It was only one night so who knows but it seems to maintain 400-450 on stove front easier than before.

 

[brenndatomu]

Shades of red, it's all about shades of red. I have seen black iron pipes red hot and be fine, but then a lil bit more toward the orange range and they will start to droop pretty quick. B.I. pipes have worked about 6 months or so at a time for me. I suppose it depends on how well they are supported too. I am gonna order some stainless pipe next time. I think I'm gonna order from these guys, they seem to have pretty good prices for small quantitys...http://www.onlinemetals.com/merchant.cfm?id=58&step=2&top_cat=1 Also, someone else here recommended these guys, they seem a bit higher to me, but still not bad http://www.metalsdepot.com/

 

[KindredSpiritzz]

I'd like to see some pictures of where your pipes go through the jacket of the furnace in the front. How did you make it air tight? weld?? And i dont quite understand how/where you came through the back with your preheat air pipes. I'd think you'd either come in thru the front or the back, not both. Just having trouble picturing it.

 

[TdiDave]

I'd like to see some pictures of where your pipes go through the jacket of the furnace in the front. How did you make it air tight? weld?? And i dont quite understand how/where you came through the back with your preheat air pipes. I'd think you'd either come in thru the front or the back, not both. Just having trouble picturing it.

I came in thru the back not the front, I dint like the idea of coming in low in front, stuffing with wood would possibly damage the pipes.
I cut about 4" of threads on the pipe then double nut with washers to the fire box, then thru air jacket I installed a bushing to seal air leak, then the nipple that I can cap.

 

[brenndatomu]

I'm still under the impression that while secondaries burn better and cleaner it speeds up burn time.

Sorry about the photo quality, I only have a 1.5" viewing port and I couldn't spend too much time in photo position for fear of melting the camera. Anyways, you can see the single Oak split in the 7-8:00 position that I threw in 10-15 minutes earlier, is not really burning much, it is actually just smoldering on a hot coal bed with just a bit of lazy orange smoky flame due to the primary air being set to the minimum "over night" mode. The fireball that you see from 9-2:00, is secondary burn, and that, is a ton of heat being made off that small smoldering fire below, heat that would have been "up in smoke" before the baffle and air tube install, not to mention the side effect of a cleaner chimney!
Point is, since the primary fire is turned down low, the wood does not seem to be "consumed" any faster. Now, once the secondary flames die down after an hour or two, I suppose that that extra air could make its way down to fuel the primary fire, but by that time the wood is pretty much charred and in the beginning coal stage, and doesn't seem to be affected by air from above that much by that point.

 

[TdiDave]

At what stove front temp would be need to get good secondary combustion ?
Would it be possible to have to few holes that push air to fast or hard out of the tube, my flames up under the baffle seem to move around rather violently.

 

[redfin]

Can anyone point me to a good thread to explain this concept?

 

[brenndatomu]

At what stove front temp would be need to get good secondary combustion ?
Would it be possible to have to few holes that push air to fast or hard out of the tube, my flames up under the baffle seem to move around rather violently.

How far are you cutting the primary and secondary back? I think I would want to put a key damper in the flue pipe and see what cutting the draft back a bit would do...
As far as stove front temps...who knows, depends on the exact model you have. I see 4-500, but that is through a heat shield, so...?
I have read that secondary combustion occurs at 11-1200*
EDIT, I just seen you already have a damper...

 

[brenndatomu]

Can anyone point me to a good thread to explain this concept?

If you do a search, you will find a boatload of secondary combustion content here on AS. Also, that other big hearth site would have a bunch too.
Do you have specific questions?

 

[redfin]

Well I have mostly passed over a lot of the threads regarding "secondary burns" due to the fact we were planning on moving and I didn't want to dork with the energymate box we use.

Looks like we will be here longer than we thought and after reading this thread it seems I could get better effieciency if I had somewhere to really start reading.

My box eats the wood. It has an ash pan and vent on the door that is all manual. I do not mind at all regulating manually just looking to get some longer burns overnite.

I willl search for some more threads.