Minor Explosion In Coal Stove

I honestly don't know why I never switched earlier.

Same here!

Hi all; Puff Backs.... got up on the roof and placed three bricks on end around the flue collar, then set a flat rock on top, end of problem. Next year bought a fancy topper for the chimney. It promptly rotted away, put the bricks and rock back. Thats how it is today.

Just a reminder 3 screws in those Baro's...
Forgot to replace mine...
Blew the baro across the room during startup...

I had an impressive puff back during the first couple of days I had the stove fired up this year. I was running the stove at idle and forgot that I needed more over the fire air to disperse the built up combustible gases that gathered due to the weak draft. I had just closed my ash door after having it open for a few minutes to revive the fire after 12 hours of burning. The new flames set it off. POOF! Thankfully, I had used 3 screws at each joint when I put it together. I had just moved to the front of the stove to open the load door and watched the whole thing develop; it was an out of body type thing. The whole stove jumped and flyash come out the door gaskets. My husband was impressed but I knew immediately what I'd done wrong. It wasn't a good thing. The goal is no puff backs. Be safe, Lisa

Had two small ones tonight. I could see the flashes through the air inlet on the ash door. Thought I was doing good, no puff backs since September. Oh well, can't win them all.

IOF, how was the stove set up when you got the puff back? This year I have been leaving one side top air vent open all the time and when I load it up I shut the ash door right away and open the bottom air vent for a while till the stove temp comes back up to 350* then set the damper back down for a 12 hour burn. Last year I had a few puff backs and it seemed it was always after loading and the ash door was left open to bring it back up to temp.

I haven't had one yet this year. I have noticed that some coal produces more gases then others, in the past after refilling the stove and waiting for the coal to catch I could see flames in the smoke pipe through the baro, I haven't seen it yet with the coal I'm currently burning.

JB Sparks wrote:IOF, how was the stove set up when you got the puff back? This year I have been leaving one side top air vent open all the time and when I load it up I shut the ash door right away and open the bottom air vent for a while till the stove temp comes back up to 350* then set the damper back down for a 12 hour burn. Last year I had a few puff backs and it seemed it was always after loading and the ash door was left open to bring it back up to temp.

I just had the air inlet on the ash door open about 1/2 way. I don't generally do anything with the secondaries on the side of the stove. For a while I was opening both sides up as well as the damper but I found it was burning up my coal. So now I just leave them closed.

When I filled up this evening I had thought about opening one side but forgot about it when my daughter started to cry.

Hmmm, I'm for sure no expert but I don't see why leaving the side top air open will cause the stove to burn the coal any faster. I'd like to hear what others think about this. I do know it has helped prevent the puff backs.

JB Sparks wrote:Hmmm, I'm for sure no expert but I don't see why leaving the side top air open will cause the stove to burn the coal any faster. I'd like to hear what others think about this. I do know it has helped prevent the puff backs.

Secondary air actually slows down the rate of combustion AND, when you put on a fresh batch of coal it increases your combustion efficiency by quite a bit. I can throw an entire scuttle of coal on the Glenwood and it will not puff back because it gets controlled secondary air to ignite the gas before it builds up enough to puff back. Leaving the ash pit door open to allow the fire to get very hot is probably the most common cause of back puffs. When you throw on a bunch of fresh coal on an overly hot fire a whole lot of gas gets cooked off of the new coal really fast as the new coal is cooling off the fire under it. This sets the stage for a back puff when the air, heat and gas mixture hits that ignition point and boom. There you go.

Thanks William, I was hoping to hear your views on this subject. From what i have learned so far running the Chubby, I believe you are exactly right on.

So, I'm assuming I should possibly start using my secondaries? How do I know when I should use 1 or both? And for how long should they be left open? Do I still follow SOP and close the MPD after 2-3 minutes? Or leave it open for as long as I leave the secondaries open?

I'm On Fire wrote:So, I'm assuming I should possibly start using my secondaries? How do I know when I should use 1 or both? And for how long should they be left open? Do I still follow SOP and close the MPD after 2-3 minutes? Or leave it open for as long as I leave the secondaries open?

You leave the secondary air supply open until you get those nice blue flames going strong. I would open both of them after loading the coal. Also don't let the fire get too hot just before you put on some fresh coal. Let the coal ignite slowly. You can go ahead and close the pipe damper the same as you did before. Once you get the blue flames then you can set your ash door damper for the long term burn and close the secondary air.

and just tonight my Chubby did a mild puffback

these things come in threes so there is one more to go

Did you have the side air vents open when you had the puff back?