RogueRose
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Woodstove "puffing" (flashing?) when full of wood and closed
I've noticed that my wood stove will "puff" - meaning it blows smoke out of the air inlet and sometimes the flue pipe off the chimney mantle. This
happens when wood is put in the stove and it is closed up for some time. It usually happens when there is a nice bed of coals for the new wood to sit
on when it is closed up. The wood that is used is quite dry (not kiln dried but close). I saw this happen for the first time the other day and was
startled at the velocity of the gases escaping the air inlet valve. I've been told that once in a while there is a slight flash immediately
afterwards.
I'm trying to figure out exactly what is happening and if it is potentially dangerous. This has happened many times and it never has seemed
dangerous as there is nothing around it that can be damaged or burnt. Is this similar or the same as when fire fighters deal with a "backflash".?
I'm guessing the wood is heated by the coals, not really burning, basically turning the wood to charcoal. In this process it seems that both CO and
CO2 are produced with the CO being flammable. I'm just wondering what initiates the ignition/flash to make the stove puff?
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violet sin
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The wood is starting to char and releases flamable vapors, which rise up the chimney pulling in more oxygen. So you have a nice flamable char gas and
oxygen but no flame, drafting faster. Coals finaly ignite the mix and a "poof"is heard. Ive seen a smoke ring puff out before, prety cool. Open air
version is after sweeping the yard of pine needles, burn them. A huge bunch will dowse the flame, thick smoke will creep out and woof finally pop
off.
If you have sparks belched out or too violent of a pop, may be a little problem. Be a shame to puff sparks out of chimney sections in a dry attic
though. The geometry has never made for explosive or violent ignition in my experience, worst was a nice strong whoosh. But still a push not pop
scenario. I would think about doing a sweep if this is new issue, maybe 20 min of work for some peace of mind.
If your'e still worried steel tape can be purchased for the joint in stove pipe sections. No fun crawling up into the attic to do it. Especially if
there was a recent fire made. We have always had wood stoves, so you get use to the quirks n what is not right.
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Morgan
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As an aside, sometimes a stove will build up feedback.
https://www.youtube.com/watch?v=GeQ931v2shQ#t=1m47s
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