Volatiles-Based Chimney Fire

I had one heckuva scare this morning.

Last night, I finished the movie I was watching around 2am. I chucked a hod of bit in the 400 degree stove and left a corner uncovered. Waited for new fire to sprout and went to bed.

My alarm clock goes off at 6 and I noticed the house was a bit cool. After checking the thermometer and seeing 275,I figured the load from last night had smothered the coal bed. I was wrong. When I opened the load door, the back half of the bed had burned/collapsed. The front had bridged tight and left about 2 inches of unburnt coal. I poked it and suddenly was staring into the center of a nuclear reactor.

The stove top temp shot past 500 and, like the idiot I am, I threw im an entire hod of cold bit from outside in an effort to slow the draft. It worked but thick, yellow smoke started billowing out of the coal pile. Within seconds, the coal gas started igniting in the pipe.

The baro flew open and the draft flapper slammed shut as I watched the lazy red flames in the pipe mature to an angry orange/yellow.

I opened the load door and turned the thermostat down to kill primary air. I started piling on ashes. I shut the baro with a gloved hand. Still it burned.

Finally, it seemed to have lost enough draft to start cooling below the self-sustaining ignition point and the fire went out. Within 20 minutes, everything calmed down and the stove was operating normally with the new charge starting to catch.

I know I did a lot of wrong things. I also know that I didn't have a clue what the right things to do would have been.

What should I have done differently? I figure the problem started with the load at 2am.

voodoochylde wrote:
The stove top temp shot past 500 and, like the idiot I am, I threw im an entire hod of cold bit from outside in an effort to slow the draft. It worked but thick, yellow smoke started billowing out of the coal pile. Within seconds, the coal gas started igniting in the pipe.

Seems like here is where you went wrong with adding fresh fuel to the out of control coal bed. Perhaps just shutting the stove and turning down the air would have been a better choice?

For that quick a flair-up, I'd have used ashes to slow it down, not more fuel. Once it's back under control, then you can shake 'em out and slowly add more fuel.

I think the "cool it with more coal" trick only works well with anthracite ?

Paul

I had some bit fires go nuclear too. My strategy was to cut the primary air completely and crack the load door open so the gases could burn instead of letting them accumulate and flash. It worked, but there are a few minutes that it seems out of control until the bottom of the coal bed cools down some.

Sunny Boy wrote:
I think the "cool it with more coal" trick only works well with anthracite ?

Paul

Seems to make sense, a fuel that doesnt release nearly as many volatiles as bit when you are trying to cool the fire. Perhaps the higher density of anthracite absorbs more thermal energy from the fire as well.

As long as your stove is airtight, and your smoke pipe well-fitted and screwed together, shut down the primary air entirely and close down the secondary air almost entirely ~ 98%. Don't add fresh fuel and don't open the stove to shovel ashes, coal, or anything else on it. leave it closed up and wait a few minutes for the fuel bed to cool down and settle.

Berlin wrote:As long as your stove is airtight, and your smoke pipe well-fitted and screwed together, shut down the primary air entirely and close down the secondary air almost entirely ~ 98%. Don't add fresh fuel and don't open the stove to shovel ashes, coal, or anything else on it. leave it closed up and wait a few minutes for the fuel bed to cool down and settle.

It's a Locke Stove Company Warm Morning 818. There are no gaskets on the stove aside from the high temp silicone I laid in at the mouth of the ash pan door and the extra thermostatically controlled air intake.

I've always been told to never shut off the primary air completely with a hot coal fire, because that's one of the ways grates can get warped/cracked.

I have seen old stove operating instructions (non-air tight stoves) that say to put ashes on top of a too-hot coal fire to slow it down.

Paul

Every stove and setup is different. My recommendations only reflect what actions I would have taken on a stove in that situation (provided the stove and smoke pipe clearances to combustibles are all adequate).