Alaska Kodiak-Secondary air over fire?

Alaska Kodiak-Secondary air over fire?

PostBy: 63roundbadge On: Sun Dec 16, 2012 4:18 pm

I keep reading posts about varying secondary air over the fire. I don't believe I have that option w/my hopper fed Alaska Kodiak? All I have is primary air via the front ash door shutter.

I'm having no problems, virtually idiot-proof operation (fortunately); I'm just curious what necessitates air over the fire?

Is this only w/chubby style stoves?
63roundbadge
 
Stove/Furnace Make: Alaska
Stove/Furnace Model: Kodiak

Re: Alaska Kodiak-Secondary air over fire?

PostBy: Boots On: Sun Dec 16, 2012 6:42 pm

i have a hand fire boiler,it has aver fire air. I just recently started using over fire air to help me eliminate a "puffback" issue i was having. In my case it allows enough oxygen into the firebox to continually burn the gasses released by the fresh coal, rather than them being ignited all at once AKA BIG BOOM!!!
Boots
 
Stoker Coal Boiler: Keystoker KA-6
Hand Fed Coal Boiler: Burnham SFB 101 (sold)

Re: Alaska Kodiak-Secondary air over fire?

PostBy: mkline On: Sun Dec 16, 2012 7:30 pm

If you open the front door and look straight down you'll see a space between your firebrick and the body of the stove.The Kodiak gets it's overfire air from the ashpan door.It's also a good idea to keep that area free of ash.I just use a shopvac to clean that area.

Mike
mkline
 
Hand Fed Coal Stove: Alaska Kodiak x 2...Old and New
Coal Size/Type: Nut and Stove/Anthracite

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Re: Alaska Kodiak-Secondary air over fire?

PostBy: Lightning On: Sun Dec 16, 2012 8:19 pm

I have a Clayton, which also had these passages for ash pan air (primary combustion air) to come up over the fire. I found that thru my 12 burn as ash would accumulate on the grates, my combustion air would bypass the grates, and my fire would slowly starve. Sometimes resulting in loosing the fire or just not having a steady heat output. But, my grates are handicapped by their design and you may not have this problem.

So, what I did was close off these passages so combustion air is forced to come up thru the grates, and cannot re route up over the fire, carrying heat out the chimney with it. For secondary air, I have a flap valve on the back of the fire box on a port that would otherwise be used for a motorized draft inducer.. I've found that having independent control of primary and secondary air has given me the ability to fine tune the burn and keep my burn much more efficient with less heat going up the chimney, more heat making it into the house.
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Alaska Kodiak-Secondary air over fire?

PostBy: 63roundbadge On: Sun Dec 16, 2012 9:05 pm

mkline wrote:If you open the front door and look straight down you'll see a space between your firebrick and the body of the stove.The Kodiak gets it's overfire air from the ashpan door.It's also a good idea to keep that area free of ash.I just use a shopvac to clean that area.

Mike


THANKS SO MUCH MIKE! That makes sense. I thought the slots there were only to keep the window clean. When shaking, I can see the air coming up and washing over the glass.

I never tied the blocking of the slots to the puffbacks I get after shaking. Now I know why.

There's so much knowledge and experience on this forum!

Thanks,
John
63roundbadge
 
Stove/Furnace Make: Alaska
Stove/Furnace Model: Kodiak

Re: Alaska Kodiak-Secondary air over fire?

PostBy: rberq On: Sun Dec 16, 2012 9:51 pm

When there is new coal giving off gas, air above the coal is needed to burn the gas. But after an hour or two, and the firebox is full of red coal with no flames, is that extra air needed? Or does it just carry more heat up the chimney?
rberq
 
Hand Fed Coal Stove: DS Machine 1300
Coal Size/Type: Nut -- Kimmel/Blaschak/Reading
Other Heating: Oil hot water radiators, propane

Re: Alaska Kodiak-Secondary air over fire?

PostBy: Poconoeagle On: Sun Dec 16, 2012 10:04 pm

the slot on the back side of the hopper near the top is to allow circulation of air also.
the 4 glass wash do give air over but are designed as a glass wash.

i can get some nice WOOOSSSHHHH and blue flames when opening the hopper lid :D seems draft related


bit coal and wood burners need air over fire...mostly

the amount of air going in is fixed via your adjustment and the glass wash air dosnt affect the end result of draft at the breech. watching the rear adjustment/air inlet does change
Poconoeagle
 
Stove/Furnace Make: Buckwalter & Co. , EFM520
Stove/Furnace Model: No. 28 Glenwood 1880, Alaska

Re: Alaska Kodiak-Secondary air over fire?

PostBy: buck24 On: Sun Dec 16, 2012 11:30 pm

I see it that a lot of the stoves that burn coal/wood have these secondary air ports for over the fire air when burning wood. Most of the box style stoves made to burn coal do not have secondary openings over the fire. Some stove manufacturers state that thier glass windows in the door has an air wash system which allows air to come in by eliminating a strip of gasket on the window. Personally, I want my window sealed on all 4 sides. If I want air to mix with the gases I keep the feed door open a crack (1/4) when reloading the Buck Model 24 Stove and she does just fine. I really don't think there are that many stoves out there with the secondary ports built into the stoves that are intended to burn coal.
buck24
 
Hand Fed Coal Stove: New Buck Corp. / MODEL 24 COAL
Coal Size/Type: Pea, Nut / Anthracite

Re: Alaska Kodiak-Secondary air over fire?

PostBy: Lightning On: Mon Dec 17, 2012 4:14 am

rberq wrote:When there is new coal giving off gas, air above the coal is needed to burn the gas. But after an hour or two, and the firebox is full of red coal with no flames, is that extra air needed? Or does it just carry more heat up the chimney?

Here is what I've learned about the secondary air issue:

Importance of Over Fire Air & Blue Flames
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Alaska Kodiak-Secondary air over fire?

PostBy: 63roundbadge On: Mon Dec 17, 2012 12:59 pm

Poconoeagle wrote:the slot on the back side of the hopper near the top is to allow circulation of air also.



Yeah, I looked at that slot and wondered how many times the engineers burned the hair off their hands and eyebrows before they caught on to that need! Otherwise all that gas would be looking for the first chance to unite with air...
63roundbadge
 
Stove/Furnace Make: Alaska
Stove/Furnace Model: Kodiak

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