Whuffing Every Time!

[Eightball1313]

I have an old Kodiak Stove with double doors and an air inlet on each door. Ever since ive owned the thing ive noticed that with the air inlets open all the way or most of the way that it "whuffs" very rapidly. Once in a blue moon it will back puff smoke but that rarely happens, i just hate the whuffing sound and am wondering how to stop it or why it does that. Once i get the fire ripping its usually whuffing pretty hard but as i dial it down to cruise for a long burn the whuffing will go away, it just kind of makes me nervous when im building the temps up and the stove is whuffing so rapidly. It will do it after cleaning the chimney and it will do it after burning a few months and not cleaning the chimney so i dont think it has anything to do with the chimney being gunked up or anything.

i will point out that i have an 8 inch outlet on the stove and reduce it down to the 6 inch right away to go into my thimble. Yes i know this is frowned upon, could that be the issue?

Looking for opinions!

 

[bholler]

I have an old Kodiak Stove with double doors and an air inlet on each door. Ever since ive owned the thing ive noticed that with the air inlets open all the way or most of the way that it "whuffs" very rapidly. Once in a blue moon it will back puff smoke but that rarely happens, i just hate the whuffing sound and am wondering how to stop it or why it does that. Once i get the fire ripping its usually whuffing pretty hard but as i dial it down to cruise for a long burn the whuffing will go away, it just kind of makes me nervous when im building the temps up and the stove is whuffing so rapidly. It will do it after cleaning the chimney and it will do it after burning a few months and not cleaning the chimney so i dont think it has anything to do with the chimney being gunked up or anything.

i will point out that i have an 8 inch outlet on the stove and reduce it down to the 6 inch right away to go into my thimble. Yes i know this is frowned upon, could that be the issue?

Looking for opinions!

It is pretty normal with old stoves like yours. Don't open the draft caps as far

 

[BIGChrisNH]

My father-in-law's old Ashley does that sometimes. My guess always was that gas builds up in the firebox and then finally gets hot enough to ignite so "POOF"

 

[Corey]

The continual 'whuffing' / chugging sound I suspect the big fire burns up all the oxygen and backs up the flue with smoke - both of which cause the fire to die down. In the 'die down' state the flue can empty the smoke and fresh oxygen comes through the vents which causes a flare-up, consuming all the oxygen and backing the flue up with smoke... the cycle repeats. Depending on several factors, this cycle could repeat anywhere from several times a second - making a low rumble sound to once every few seconds which could be distinct 'puffs'. Search for 'pulse jet' or 'buzz bomb' for more in-depth details.

Generally 'all the way open' isn't the hottest burning stove. Generally you need to look at it like a carburetor - you need 'just the right mix' of fuel/wood and air for best operation. So as mentioned, the simple fix is simply don't open the air that far.

If it only goes 'whoof' once - that's typically more of a 'backdraft' situation... usually a bed of hot coals and you add a mass of new wood which starts to smoke but doesn't light. This can fill the whole firebox and flue with volatile wood gas, then finally a spark lights it. Sometimes this is reported as being a fairly violent 'boom'.