Boom then a puff of smoke?

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BXTF

Member
Hearth Supporter
Aug 30, 2008
64
Rock Tavern, New York
Loaded up my Jotul F400 this morning, waited about 30 minutes for it to get going. Not much was happening so I open the door to take a peak. After I closed the door about 15 seconds later I heard a boom, then a puff of smoke came out the back. Fire started to burn and the stove was burning normal. This is the first time this has happen (scared the **** out of me at 3 AM :bug: ). Can anyone please explain what happen.
 
You had a small explosion of wood gas (smoke) + air inside the stove. Probably not dangerous. By opening the door you probably let in enough extra air for most/all of the accumulated wood gas to ignite at once. To avoid this, make sure you have active flame before closing the door.
 
You may have failed to achieve a draft up the chimney, cold air pushing down, and not enough heat to start the draft. Hence, the result explained in the prior post. You may want to pay more attention to getting a draft started before closing the door if this happens more frequently, or it may happen only in certain unique circumstances of outside wind, temp and humidity and inside temp.
 
This happened to me when I was new to the Castine. Scared the crap out of me. From that point on, I always left the door open about 1/4" until strong flames were visible and the fire had a good start. It never happened again following that procedure.

It's called backpuffing. The firebox was filled with either too large pieces and not enough small pieces to ignite right away. These pieces probably didn't have enough hot coals to start them, so they smoldered instead of igniting into flame. Opening the door gave a rapid shot of air. Closing it again, started the smoldering, but this time a flame finally started. As soon as it did it ignited the firebox full of hot wood gases. Poof! or more like KaWhumph! Now you know why there are 3 screws per pipe joint. ;-)

For restarting, move the coals to the front center. Put a little kindling on them, then put two short 2" splits, North/South about 4" apart. Put the rest of the splits East/West on top of the two short splits. If the kindling hasn't ignited, blow on it to start. Then close the door, but leave it ajar 1/4-1/2" until the fire is burning well.
 
You have just experienced a "backdraft". A situation where the temp was high enough but the oxygen was low enough to not ignite the volatiles. Oxygen was introduced and POOF.

To avoid this in the future, make sure you have a good draft or a cracked door or open primary air or a combination of these, so that a dangerously low oxygen environment is not created. This will typically only happen on start up. Once the fire is established, you really shouldn't have any problems.

By accident, I created this situation ONCE....and it was a good one. Scared the heck out of me and rattled my 600 pound cast iron stove.

Edit: BG must have been looking over my shoulder when I was typing. ;-P
 
Thank you. just learned a whole lot. BeGreen you were right the noise did sound like KaWhumph. Not a nice sound at 3 AM. :lol:
 
Mr Crabs,

Could it have been a split or a round just falling lower and settling in the fire-box?

Noises are always louder in a quiet house.
 
I start work at 4 AM. I'm reloading before I leave at 3:45. And it diffidently wasn't a split falling. I made all the mistakes that folks are talking about. I packed the stove tight with large splits and they never caught, just sat there smoldering. When I open the door I gave it just the right amount of draft to heat things up and when I close the door everything was just right, then BOOM and the puff of smoke! Now I know small splits and keep the door open 1/4 inch and let the draft and flames start up, then close the door. Again thank you. I never stop learning on Hearth.com.
 
I heard one of these from my flue one day, and yes, I concur with the "scared the *(^#&$ out of me" as emoted by others...
 
I get some backpuffing but most of the stuff I've read here doesn't explain it.
I'm burning pretty much 24/7. I reload onto a really good bed of coals and get the new splits going by giving them plenty of primary air.
They catch quick and I lower the primary in a couple stages. All is well and cruising at 400-650F stovetop for 2-3 hrs.
At this time, during what looks to be the "heart" of the burn, it'll start to backpuff. Usually it's just a rolling ball of flame but sometimes it's enough to lift the topload door and send a puff of smoke into the room. What I've read suggests that it's starving for air but it looks like a good fire and if I give it more air it'll head for 700F+ in no time so I've been just accepting it. I kinda like a little smoke smell anyway. :coolsmirk: It usually only does it for 10-15 minutes and then seems to settle back in to it's normal burn. So...is this normal or should I be looking for a solution to prevent it ?
 
Brian VT said:
I get some backpuffing but most of the stuff I've read here doesn't explain it.
I'm burning pretty much 24/7. I reload onto a really good bed of coals and get the new splits going by giving them plenty of primary air.
They catch quick and I lower the primary in a couple stages. All is well and cruising at 400-650F stovetop for 2-3 hrs.
At this time, during what looks to be the "heart" of the burn, it'll start to backpuff. Usually it's just a rolling ball of flame but sometimes it's enough to lift the topload door and send a puff of smoke into the room. What I've read suggests that it's starving for air but it looks like a good fire and if I give it more air it'll head for 700F+ in no time so I've been just accepting it. I kinda like a little smoke smell anyway. :coolsmirk: It usually only does it for 10-15 minutes and then seems to settle back in to it's normal burn. So...is this normal or should I be looking for a solution to prevent it ?

Is your rig set up in your basement?
 
I have had one of those explosions since I got the new stoves. What was really exciting was with the older big firebox "airtight" inserts. They would be damped down tight and the load would smolder and starve for oxygen and on occasion the load would grab for air the only place it could find it. It would pull it back down the masonry chimney and there would be a huge explosion in the firebox. Well, that was when you found out they were not exactly airtight and the room would fill with thick smoke when it blew out of every leak and seam.

And things would depart your body through every leak and seam too. :lol:
 
Brian VT said:
mikepinto65 said:
Is your rig set up in your basement?

Yup.

Whatcha thinking might be the issue ? Stack effect for just a short period during the burn ?
 
Brian VT said:
Brian VT said:
mikepinto65 said:
Is your rig set up in your basement?

Yup.

Whatcha thinking might be the issue ? Stack effect for just a short period during the burn ?

Me thinks it might be a cold air pocket in the stack- when you start it, run outside and see what is or is not coming out of the chimney.
 
Wildsourdough said:
Brian VT said:
Whatcha thinking might be the issue ? Stack effect for just a short period during the burn ?

Me thinks it might be a cold air pocket in the stack- when you start it, run outside and see what is or is not coming out of the chimney.

I'm not starting it. It runs 24/7 and it happens during a normal hot burn with the secondary engaged.
I will look outside next time during the puffing session.
 
Brian VT said:
Brian VT said:
mikepinto65 said:
Is your rig set up in your basement?

Yup.

Whatcha thinking might be the issue ? Stack effect for just a short period during the burn ?

Could be, my stove is set up in the basement and it's happend to me once or twice as well. I've been looking into draft inducers but im not sure if it'd be worth the hassle. I think i might try and oak first but I cant seem to find one for my stove. I know I can make one but Im having troubles figuring out a way around the flap intake.
 
I should probably clarify; Im not getting regular puffs of smoke, but occasional "booms" only twice with smoke released from the secondary air intake opening.
 
Wildsourdough said:
Brian VT said:
Brian VT said:
mikepinto65 said:
Is your rig set up in your basement?

Yup.

Whatcha thinking might be the issue ? Stack effect for just a short period during the burn ?

Me thinks it might be a cold air pocket in the stack- when you start it, run outside and see what is or is not coming out of the chimney.

When it happend to me I went outside and saw a large amount of smoke that was released from the chimney....its like it got hung up on something
 
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