What are the advantages and disadvantages of blocking the air booster hole on modern wood-burning stoves?
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Air booster hole,
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Some folks do it for more control, as EPA stoves tend to allow more air in so they “burn cleaner” (read; less smoke, shorter burn time). So if you like to run your stove long and low, you may find it advantageous to block at least part of the air bypass inlet.
If you have a tall chimney leaving the holes open can cause overdrafting.
Yeah height of your chimney can make all the difference wether you will see an advantage or not. I found blocking my boost air on my F45 did make a difference slowing the stove down on my 22’ straight up 6” chimney. I also blocked some secondary air to help out as well.
My previous Jotul 602 was on this same chimney and now it’s on a 14’ straight up chimney in my workshop. It likes this shorter chimney much better.
My new Fireview has no secondary or boost air and is much more controllable.
A pipe damper is also a good thing to consider for more control. I never tried one on my Jotul’s but I did install one for the Fireview but don’t think I’ll use it much.
My previous Jotul 602 was on this same chimney and now it’s on a 14’ straight up chimney in my workshop. It likes this shorter chimney much better.
My new Fireview has no secondary or boost air and is much more controllable.
A pipe damper is also a good thing to consider for more control. I never tried one on my Jotul’s but I did install one for the Fireview but don’t think I’ll use it much.
MongoMongoson
Feeling the Heat
We have a high draft. Shutting the boost air down helps us not have a runaway fire. Additionally, the coaling stage lasts a lot longer with no boost.
The downside is that it does not start a fire quite as well from coals. I used to add fuel to weak coals, close the door and have a raging fire quickly. Now I will have more coals left when it is time to reload, but I might have to use my bellows and keep the door cracked for a bit after reloading.
Also, with the boost shut down completely, we can now have "pure secondary" burns with all the flames between the baffle and wood. With the boost open, we would have a firebox where everything was consumed with wild flames. It put out a lot of heat but went through wood faster.
The downside is that it does not start a fire quite as well from coals. I used to add fuel to weak coals, close the door and have a raging fire quickly. Now I will have more coals left when it is time to reload, but I might have to use my bellows and keep the door cracked for a bit after reloading.
Also, with the boost shut down completely, we can now have "pure secondary" burns with all the flames between the baffle and wood. With the boost open, we would have a firebox where everything was consumed with wild flames. It put out a lot of heat but went through wood faster.
I'll second (or third) the comment about helping control the draft and extend the burn. I have a Woodstock Keystone with a 27' tall chimney, tamed a little bit using the back exhaust, but still has quite the draft. The catalytic converter resistance to airflow tames the draft some, and I also have a pipe damper. But when it is really cold (near 0 degrees F or below), I'll slide the magnet on the back of the ash pan over the tiny hole for "extra air" and it is the magic adjustment that helps the stove burn normally along with primary air shut to 0 and pipe damper at 30%.
In shoulder seasons, I'll also use it to extend the "warming" time when the wood is in the coaling stove, and if is warm enough outside I'll get a small load of biochar out of my stove at then end of a 24 hour burn - biochar is great for the garden, so I don't mind producing 10 or so gallons of it every year.
In shoulder seasons, I'll also use it to extend the "warming" time when the wood is in the coaling stove, and if is warm enough outside I'll get a small load of biochar out of my stove at then end of a 24 hour burn - biochar is great for the garden, so I don't mind producing 10 or so gallons of it every year.
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