Adding Air Control on Fixed Burn Rate Stove

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jbart

Member
Oct 17, 2022
35
Michigan
I am thinking of adding an air control to my MF Fire Nova 2 fixed burn rate stove. The air inlet to the stove is in the rear so the plan would be to hook up a make up air kit hose to the inlet and attach the other end to an hvac damper. The whole set up should be about two feet long to go from the back of the stove to the side so that the damper can be accessed. With that being said is this a bad plan to damper with a homemade air control? I figured worst case I could turn the air down too low and get some smoke back into the house. This stove can really get warm with stove top temps up around 800F at times. By slowing it down I would like to think I could control heat output and improve burn times. Has anyone tried something similar to this before?
 
How tall is the flue system on the stove? If the draft is very strong, would a key damper on the stove pipe be out of the question?
 
I see. 17' is a normal height. That should not be an issue. Another option is to mix in thicker splits.
 
Just an update but I added an air control to the Nova 2 and am seeing longer burn times now. It was a worth while investment. It cost me around $40 in parts.
 
That is interesting, is your glass getting black and are you seeing more smoke out the chimney?
The glass does not stay as clean and does blacken but a hot fire will clean it. I have not noticed an increase in smoke. I think the cat does a good job burning most of it. I should have a better idea as the burning season progresses. Attached is a photo of the damper.
[Hearth.com] Adding Air Control on Fixed Burn Rate Stove
 
That is interesting, is your glass getting black and are you seeing more smoke out the chimney?
After spending more time buring with the air control I have found my stove does produce more smoke out the chimney. Even when the cat is glowing red and stove top temps are around 600 there are still times I notice it. I am not entirley sure what this means. I would assume the cat would burn most everything.
 
After spending more time buring with the air control I have found my stove does produce more smoke out the chimney. Even when the cat is glowing red and stove top temps are around 600 there are still times I notice it. I am not entirley sure what this means. I would assume the cat would burn most everything.
Do you have a moisture meter?

The cat is not big enough to “burn” the amount of smoke you are sending through it. Black glass means the firebox isn’t hot enough. This was designed to run hot fast and clean with a fixed burn rate. Everything was designed to operate together for that narrow sweet spot.

Things to check/explore
MC of wood on a room temp fresh split face
Optimal split size
Loading arrangement

your experience is somewhat common to fix burn rate stoves.
 
Do you have a moisture meter?

The cat is not big enough to “burn” the amount of smoke you are sending through it. Black glass means the firebox isn’t hot enough. This was designed to run hot fast and clean with a fixed burn rate. Everything was designed to operate together for that narrow sweet spot.

Things to check/explore
MC of wood on a room temp fresh split face
Optimal split size
Loading arrangement

your experience is somewhat common to fix burn rate stoves.
Yes, I am burning ash that is always below 20%. The glass will get partially black but never any worse that other stoves ive seen burning low and slow. It clears up mostly if I leave the air control open. I will check my stove pipe in the next month or so to see what type of build up I am getting in it. Currently, I only have about 1 facecord through it for the year burning mostly nonstop since the end of October.
 
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can you post a photo of that damper, inside? IIRC inside has a restriction even when is full open which causes turbulence above all ( bad )
 
This is the damper in the open and mostly closed position.

I agree Mellow. No complaints on burn time.
View attachment 319327 View attachment 319328
It's not what I thought, It's a good damper. Said this, I advise you to open the damper completely at each recharge and not to close it too much even if you have the cat, I use a damper similar to that one, another stove, another story, in any case, to avoid finding the stove cold after 10 hours, I close the damper up to a certain point mainly after the first hour of flames, in that phase it is counterproductive to reduce oxygen if there is a lot of wood inside, just minor adjustments at that stage. Then when the stove is full of coals I close it almost completely, and those coals will last up to 24 hours.
 
It's not what I thought, It's a good damper. Said this, I advise you to open the damper completely at each recharge and not to close it too much even if you have the cat, I use a damper similar to that one, another stove, another story, in any case, to avoid finding the stove cold after 10 hours, I close the damper up to a certain point mainly after the first hour of flames, in that phase it is counterproductive to reduce oxygen if there is a lot of wood inside, just minor adjustments at that stage. Then when the stove is full of coals I close it almost completely, and those coals will last up to 24 hours.

Just think, you could do all that with a twist of a dial on a Blaze King at the beginning of the burn ;lol