Minor Explosion In Coal Stove

--------Edit by Richard----------
I will note for those finding this topic through Google this problem is not particular to any manufacturer. The explosion being discussed here is all bark and no bite and it's not necessarily a safety issue unless you have not secured your flue pipe properly. Please read the thread before making any assumptions as this issue can be avoided entirely.
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This morning I shook the stove and added coal, later I filled it up. I probably added too much coal too soon. I went to take I shower and abt. 10 minutes later my wife said there was some kind of loud pop from the stove. We could also smell combustion around the stove. I think I filled it too soon and some gases built up in the firebox and then ignited.

Any comments?

Thanks.

What happens is the fresh coal has an amount of 'volitiles'. Think of this as if the coal had trapped flammable gas inside. These gasses are released when the coal is heated.

If you add a large enough quantity of coal that it covers the whole firebox and covers the entire existing burning coalbed, then there is no open flame to ignite the gasses when they are released from the fresh coal. The gasses build up in the firebox, and eventually a little flame makes it's way up through from the hot coal underneath, and ignites the gasses. A small explosion is the result.

To prevent this from happening, when you add fresh coal, leave a corner or end of the hot coal uncovered. The flame from the hot 'old' fire will act like a 'pilot light' and burn off the fresh gasses slowly, as they are released, instead of explosivly, all at once.

This is 'banking the fire'. Once the new coal has caught, and is burning red, you can rake it level and top off the firebox with additional coal.

Hope this makes sense.

Greg L

If you were to see it happen, you would probably be
more concerned! It is a little exciting, especially
when a poof of ash blows out of the air and
barometric dampers. I'm learning how
to load like LSFarm has mentioned, and it doesn't
happen hardly at all any more, just a couple times
a season when I rush things.

LS, are there any recorded problems or danger
to this happening? Can it ever be too big to
cause a problem?

Has anybody seen what happens at the chimney?
that would be interesting , maybe.

I'm with ya Wood! I had the same thing happen:
http://nepacrossroads.com/viewtopic.php ... kfire#4413

But now I know how to prevent it.[/url]

Hi Dutch, if you open the firebox door at the wrong time, the gasses can ignite right in your face. I think Richard [forum admin.] 's brother singed his eyebrows this way.

The other issue can be that the 'explosion' can push the chimney flue apart at the joints and can damage a baro-damper. If the chimney pipe joints are fastened together with three or four screws per joint, it is unlikely that the pipes can come apart.

I had a rather spectacular gas-ignition in my big boiler. This was when I was hand loading it with bituminous. The firebox volume and the airspace volume of my boiler is quite large, you could put a Harman MarkI inside the firebox.... so the volume of explosive gas was quite large, and the resulting 'explosion' was rather spectacular. A big belch of black soot and smoke [bituminous coal] came out the chimney, then nothing... So I went back into the boiler building to find the chimney flue had blown off and the entire inside of the building was coated with a layer of inky-black soot...
I vacuumed up what I could, even the walls and ceiling. Later the next summer I power-washed the interior of the building. What a mess. I'm really glad it wasn't inside my house.

Greg L

As Greg stated make sure all of the stove pipe joints have 3 to 4 screws
in them I already had the Baro blow off I found it about 6 feet from the
stove on the floor another thing to do is let the loading door crack open
for a few minutes after loading to let air take the gases up the chimney
also open the loading door slowly to fast and it will blow in your face I
have the scars to prove it I had a little piece of hot coal pop out and
stuck to my face last year when I was filling up the stove not to fun hurt
like hell left a little scar so be careful

dutch wrote:LS, are there any recorded problems or danger
to this happening? Can it ever be too big to
cause a problem?

Maybe for your eyebrows, ask my brother.

On a serious note as mentioned by Greg, this why you must make sure you have the flue pipes securely fastened with screws or other fastener. That's the only know danger that I'm aware of, the explosion may be enough to knock the flue off if you don't have it fastened securely.

Welcome to the world of coal heating, you have just passed the level of novice. Next, as others have mentioned, make sure the flue pipes securely fastened with screws or other fastener. You will find that the next adventures are not as exciting.

Thanks for all the replies, that was what I thought had happened. Some of you may remember my first posts earlier this year about all the trouble I was having with the stove, which turned out to be the bad coal I was buying from a local company that delivered. Since I switched to other suppliers I haven't had the problems, but I just added 560 lbs. of Blaschak coal to the top of the pile in the coal bin. This is the first time I've used this brand. I noticed that the stove shakes easier, and this is the first time I've had the gases ignite. I will bank the coals before adding from now on.

Another note: I do have the pipes held together with screws as well as the baro damper.

Thanks again to all.

I'm new and reading through to learn... glad you all went through this one and shared. It sounds like it's going to be fun! (he he?)

peanut369 wrote:I'm new and reading through to learn... glad you all went through this one and shared. It sounds like it's going to be fun! (he he?)

Yea...those were the days.

Sounds like a simple back draft.

coal berner singed his eyebrows here one time checkin out the kenmore in action

My last stove had small doors on the side to let room air across the top of the fire to help burn the natural gas that coal will give off. I have few explosions it seems.

I was just reading the articles about small explosions and itra mentioned low quality anthracite nut coal. I burned coal when I was a young boy until I was a teenager and will be making the change from wood to coal this year (hopefully) and I wasn't aware that anthracite nut coal had low or high quality. I was going to purchase coal from a local Amish who receives his coal from the Pennsylvania coal mines. The price of coal in upstate NY is high $380-400 per ton; the Amish sell it for $225 per ton. What is the best quality coal one can buy. I also see it mentioned about having bad coal. Bad coal? What makes coal bad. When I used coal as a teenager we burned the large stove coal. Did that make a difference? I am quickly trying to get up to speed; I don't need or want these small explosions. I will have one pipe connection that I do not believe I will be able to screw together. Reading today, that one connection worries me. I don't want coal dust and the like all over my hardwood floors and through the house. wayne.