Gas buildup in my Chubby

Been burning coal 4 years and this was a first. I’d been running my Chubby super low all day and thought it was time for a shake. Opened the damper and air and got her glowing...then shook her (probably too much) and all hell broke lose. It became a flame thrower. Blue flames shooting up the pipe. First instinct was to close damper. Flame went right through it. Wasn’t about to open the top door until it burned off. The sound scared the hell out of me. Next thing I did was check the chimney, thought for sure I’d see flames shooting out but thankfully I didn’t. Eventually it burned off and I was able to add coal and all seems fine now.

Everything I just read in this form said this usually happens when adding new coal.

I’m guessing there was still plenty of fresh coal in the pot and over shaking caused it to ignite the builtup gases?

Any hints on preventing this from happening again would be greatly appreciated.

Thanks!!!

Merry Christmas.

Will

My guess is this gas off event has something to do with the long, low temp burn. I'll wait for the pros to respond.

I don't think it was built up gas as it would have exploded.

It does seem to me like a great deal of coal on the edge of giving up its gas. With more heat and air from the shake it went up in flames. It behaved like pre-heated coal from a hopper often will. Blue flame, and a lot of it, very quickly.

A very high fire will have orange in it as bits of carbon break loose. Yours was blue. There probably was some CO burning as well which would have been produced from the long air starved burn.

The Glenwood base heaters will often have blue flame burning from the gas holes, throughout a long air restricted burn, This would be CO burning. A good reason for some secondary air all the time.

Thanks. Yes I had the primary complely closed all day. Also my CO detector beeped 4 times after the shake and I opened the front door immediately.

Thanks for taking the time to reply. That explains it. Not going to completely close the primary again.

Cheers,

Will

Not to ignore the fire blowout you had but how did you get a slow burn in chubby, I can't seem to do that.
What temperature was the burn and what temp was it outside?
Here in Atlanta we go from 30°to 54° in one day. I love to slow burn and not lose fire.

When it gets around 40* or above, I run my chubby as low as possible and it’ll burn between 350* - 400* for 12 to 16 hrs. without touching it. I have the primary air and damper closed all the way. Albeit the roap gaskets probably need changed so some air is probably getting in. Hope this helps. Merry Christmas.

How is the ash bulid up when do this ? I believe ash bulid is killing fire.

Vonda, did you see that gadget someone posted about for getting ash out of a Chubby? I cant remember the posts title but it might help you. It was within the last month or a little longer, a drill attachment.

keegs wrote: ↑

Sun. Dec. 23, 2018 7:34 pm

My guess is this gas off event has something to do with the long, low temp burn. I'll wait for the pros to respond.

Not an expert by any means but it makes sense. The coal was warm enough to start offgasing,it sat there waiting for the oxygen. Ive had it happen once or twice over the past few years.

warminmn wrote: ↑

Tue. Dec. 25, 2018 6:09 pm

Vonda, did you see that gadget someone posted about for getting ash out of a Chubby? I cant remember the posts title but it might help you. It was within the last month or a little longer, a drill attachment.

I'm intrigued,I've had good luck shaking and poking like the video shows. I'd love to see a Chubby with Glenwood style grates.

ASea wrote: ↑

Tue. Dec. 25, 2018 6:12 pm

I'm intrigued,I've had good luck shaking and poking like the video shows. I'd love to see a Chubby with Glenwood style grates.

I remember someone hooking a motor up to the Chubby shaker too.

One problem Vonda may have is the TSC coal. Not trying to run it down but it makes more ash for me, the 3? years Ive used miners choice. its a guessing game though.

I remember Larry working on a Base burner Chubby too, but it may never get past the trials and errors.

warminmn wrote: ↑

Tue. Dec. 25, 2018 6:09 pm

Vonda, did you see that gadget someone posted about for getting ash out of a Chubby? I cant remember the posts title but it might help you. It was within the last month or a little longer, a drill attachment.

Yes, I remember it. I have find a welder to attach the picture.

And some people say anthracite doesn't fart! LOL!

It certainly does under the right circumstances.

I rarely run without secondary air. If I DO close the secondary air it's only to coax a lazy fire that needs more primary air.

99.9 % of the time secondary air is your friend.

McNair wrote: ↑

Wed. Dec. 26, 2018 11:17 pm

And some people say anthracite doesn't fart! LOL!

It certainly does under the right circumstances.

I rarely run without secondary air. If I DO close the secondary air it's only to coax a lazy fire that needs more primary air.

99.9 % of the time secondary air is your friend.

I run the secondary air (flaps up) when I'm burning pellet logs or when I'm starting the stove. I close them during long burns. I wonder how reburn tubes like the Anthramax stoves have would work.

I don't know Anthramax stoves. I run my cannon heater as if secondary air is bypass air. I'm not so concerned about farts, but I have learned my lessons. I HAVE had bad things happen. But at the end of the day I treat secondary air as primary bypass air.

You get to a point, I think, that you avoid explosive situations without even thinking about them.

And I do use secondary air to prevent bad days.

It's just part of the daily operations.