Smoke "Puff back" from Air Vent in Boiler

president · Dec 31, 2015

Marshy said:
Same thing happens to my Shenandoah except I don't get a light show. It pisses me off pretty good because it blows some stinky smoke into the house, generally a little fluf. It will happen in my stove in two different occasions. 1st, low burning coals or fire and I fill the firebox to the gills. 2nd, really hot bed of coals and I fill the firebox to the gills. In both cases what I found is happening is the firebox gets fill with combustible gases and they deflagrate. The best solution I found was to keep the drafts open to keep that build up of gas minimal. Also, push the hot coals to one end of the firebox (if practical) so only one end of the splits catch fire, this will reduce the amount of smoke generated initially and will gradually increase as the rest catches. Things that exacerbate the issue is poor draft due to weather conditions or stove pipe\chimney buildup. If I decide that I have to stuff it to the gills I keep my door cracked and watch to see if the firebox box gets filled with gas and if it does I light my hnd held tortch and stick it in the door opening. The extra heat fro! The torch promotes draft in the firebox and helps this gasses ignite without deflagrating.

Nice name for combustion,(Deflagrating) would that be a stove fart?

Oldman47 · Dec 31, 2015

That is a high speed burn just shy of a detonation. Detonation is explosion.

Marshy · Dec 31, 2015

president said:
Nice name for combustion,(Deflagrating) would that be a stove fart?

Basically any subsonic explosion. Here's a good example of the difference between defligrate and detonate.

Defligrate is that woof sound when you light 5 galons of gas on fire.

brenndatomu · Dec 31, 2015

svk said:
The most certain time it happens is if I fill the box completely full then as it burns down, the first time the air opens and hour or so later is when the blow back occurs.

Yup, I agree with the rest, needs more air. The paper clip trick has worked for many. When you load 'er up and then it just sits there smoldering away, you have firebox and possibly a chimney full of wood gas, the air opens up, the fire takes off and WOOF! smoke in the house. If I load the Yukon up on a ton of hot coals it will puff back sometimes. An outside air source can help if you have even the slightest negative pressure in the basement. Crack a window open and then try to make it poof...

svk · Dec 31, 2015

brenndatomu said:
Yup, I agree with the rest, needs more air. The paper clip trick has worked for many. When you load 'er up and then it just sits there smoldering away, you have firebox and possibly a chimney full of wood gas, the air opens up, the fire takes off and WOOF! smoke in the house. If I load the Yukon up on a ton of hot coals it will puff back sometimes. An outside air source can help if you have even the slightest negative pressure in the basement. Crack a window open and then try to make it poof...

But it only does it after the air vent has been open for a while. And I can leave the wood access door open to the outside so it's not a draft issue in the house.

Are we thinking that the air vent should actually be larger and this is just a design flaw?

It appears that this only happens when first firing up or when loading full. I can load it less and not have a problem. But it sure is nice to know I can wake up and not need to feed it right away.