Extending burn times with secondary air control

[pgmr]

A few months back I posted about adding a secondary air control to my Morso stove.

I'd be interested in reading your prior post, but couldn't find it via search. Would you mind posting a link to it? Thanks.

 

[precaud]

Just out of interest - when you speak of primary air, do you mean air from below (which is used for smokeless coal briquettes and provides air from below the riddling grate) or do you mean the airwash which comes in from the top of the glass (which I refer to as secondary).

In your case, it would mean both... most wood-only stoves don't have an actual under-fire air source...

The Owl also has a (fixed) tertiary air supply which takes heated air and provides air through little holes at the rear of the stove.
So, in summary: two adjustable levers - left (pri) and right (sec) - and one at the back (tert., fixed).
john

The tertiary source should give your coals enough to keep them alive overnight. On the 2110, this air enters the firebox through two holes in the middle of the log fence, in front. The USA Owls are the same way. Are you sure yours are in the rear?

The basic concept is to proveide just enough air to the bed of coals to keep them alive (and by 'alive' I don't mean glowing red), and close off all other sources of air.

 

[precaud]

I'd be interested in reading your prior post, but couldn't find it via search. Would you mind posting a link to it? Thanks.

https://www.hearth.com/econtent/index.php/forums/viewthread/2756/

It has a link to the article posted in the Wiki section too.

 

[jtcedinburgh]

On the 2110, this air enters the firebox through two holes in the middle of the log fence, in front. The USA Owls are the same way. Are you sure yours are in the rear?

Yes - at the back of the stove, above the low level firebricks, there are two rows of small holes which provide the heated air for tertiary combustion. I shall try to remember to take a picture (might be tricky).

When you say 'don't mean glowing red' - do you mean not glowing at all, or something else?

 

[precaud]

Yes - at the back of the stove, above the low level firebricks, there are two rows of small holes which provide the heated air for tertiary combustion. I shall try to remember to take a picture (might be tricky).

OK, then the Euro Owl is different from the US one.

When you say 'don't mean glowing red' - do you mean not glowing at all, or something else?

Not glowing at all would be close to correct... it's a 'controlled starvation' you're trying to orchestrate with this method... enough ambient oxygen to keep them alive, but not enough to set up strong air currents which would accelerate their burnoff.

You can also use the 'banking' technique, just shove everything into a pile at the back of the stove after the last flame of the night dies. Rake it out in the morning and you'll find live coals to start up with.

 

[jtcedinburgh]

Tried it last night - with stove-pipe surface temps of around 350F, and the last of the flames dying, I closed down both the primary and secondary air (leaving the tertiary air at the back as I can't get to it to adjust it, and even if I could it's fixed in place). This was around 2230hrs.

By 0600hrs there was precisely no heat. It was stone cold. There wasn't much of anything left, other than some fine ash - the coals had been completely consumed.

Pity, as I'd have liked the extended burn...

 

[precaud]

Hmmm... too bad, indeed. That third air source is obviously the killer.

 

[sbk12rs]

So , on my Quadra fire 3100 to extend my burn at night , completely close the primary on the bottom and crack the start up lever open ?

Just making sure I'm reading this thread right .


Getting more familiar with this stove as the cord slips away ................ TIA , Steven

 

[firefighterjake]

So , on my Quadra fire 3100 to extend my burn at night , completely close the primary on the bottom and crack the start up lever open ?

Just making sure I'm reading this thread right .


Getting more familiar with this stove as the cord slips away ................ TIA , Steven

Wow-zers . . . very old thread.

However, in the interest of passing on the knowledge . . . yes . . . in general once youv'e got a modern EPA stove up to hot enough temps you want to start closing down the air . . . what this does is two things: 1) more heat is kept in the firebox vs. going up the chimney which is good since you want more heat coming off the firebox and 2) it helps the secondary burning process . . . if temps are good you should see the secondary burn fireworks.

OK, I lied . . . actually closing down the air does a third thing . . . the thing you asked about . . . it also helps extend the burn time since less air flowing through the stove and up the chimney means the burning process is slowed up.

 

[sbk12rs]

With this last cord of "seasoned " HA ! I need to run with the primary damn near wide open just make it warm enough to keep running .

I'll be mixing in pallet wood for the remained of this season with this last load .

We'll have to wait to next season to give this tip a better try