TLC2000 Explosion Blew Apart Stove Pipe, Door Latch Bent up

Post by **franco b** » Thu. Dec. 13, 2012 12:29 pm

Now it starts to get more complicated because Steve is right to say more air will make the gasses burn more furiously. But it will only do that with a really hot fire or with the light covering of coal before shake down. With a heavy load of cold coal the fire cools off, draft drops, and with the air wide open the hot coal underneath begins to generate gas in the new coal rapidly, most of which will be blown out the chimney and does not burn until enough heat reaches the top of the load. Possible boom time. If you go outside that is the time you get a sulfur smell.

With a hot fire and a few smaller loads what Steve recommends will work well also because the heat is so intense. Here again use judgement. The load of coal should be proportionate to the heat of the fire to avoid gas build up. I do prefer to generate the gas more slowly and balance the air to match.

There are stoves like the Godin, Jotul 507, Warm Morning, and many antique stoves that have a very deep firebox that is relatively narrow. Common practice is to rev up the fire and pile coal to the top and close it up for a long burn. It can take a long time to get any blue flame to the top of the load, yet they don't seem to bang very much. They will puff frequently though if you open the top, even after an hour. Space above the fire is small so most gas gets exhausted and it tends to get generated slowly.

In your situation when you get a blue flame and after 5 minutes it goes out try a little more air and a little less air to see what happens. Does it come back if you crack the door? If so is it because it is getting more air over the fire or less air through the coal bed because of the open door? A big wide fire box like your stove has tends to be happier with a hotter fire than a stove with a more compact fire box.

Another thermometer on your smoke pipe is also handy to judge what is happening.

Post by **Lightning** » Thu. Dec. 13, 2012 5:51 pm

I'm thinking that just 5 minutes of blue flames isn't quite enough time for them to get established and the fresh coal burning good, so they aren't staying around when you close it up. I quoted this post I made earlier so you could see what I mean. At step 8, waiting for the blues to come out takes a period of time (10-20 minutes) depending on the condition of the coal bed before I put fresh on. Then step 9, from the beginning of the blues till 250 degrees on the pipe can take another 10-15 minutes. This gives the fresh coal time to get burning good and bake off volatile gases. By now the coal underneath is glowing hard (see pic below) and needs time to calm down before latching the load door. So I close the ash pan door, while the blues are dancing and let it settle to 200 degrees (another 10 minutes) and by now the fresh coal is well established burning, and the prior bed underneath it is cooling down.. The whole task takes minimum 30 minutes - 50 mins at most. Meanwhile< I have my handy remote BBQ thermometer in hand monitoring it all while I'm watching TV or sitting at the computer trying to help fellow coal burners out

Lightning wrote:This is my second season burning coal. So far I've had no puff backs this year. I have a furnace but it operates quite nearly the same as a hand fed stove. My refueling ritual goes like this -

1. Open ash pan door and shake grates. (access to the shaker is only with the ash pan door open)
2. Open the load door and beat down the coal bed, then close the load door.
3. Immediately shake the grates again. (I always tend to shake with the load door closed so the coal bed can start to rev up)
4. Dump the ash pan.
5. Open the load door - Add 3 to 4 shovels of coal (20-30 pounds). This brings it to the top of the fire bricks.
6. Then I rake it somewhat level with it mounded somewhat in the middle. Prop load door open 1/4 inch.
7. Slice and poke up thru the bottom side of the grates for better combustion air access to the coal bed.
8. Leave ash pan door open until the blues come out and my flue pipe reaches 250 degrees.
9. At 250 degrees on the flue pipe I close the ash pan door.
10. When the flue pipe temp falls below 200 degrees I'll close and latch the load door.

In step 6 you notice I have the load door propped a quarter inch open. This keeps the volatile gases from building up in the fire box. IN step 10, I've let the coal bed slow down from producing an excessive amount of volatile gases so it doesn't puff back after the load door is closed. I also leave a very small amount of air coming in over the fire at all times so gases off the top have oxygen to burn and this prevents the build up of volatile gases too. If you have a manual damper you should have it open thru this whole process. Closing the MPD should be the last on the list. I use a baro, but sometimes I'll close the MPD 3/4 closed when its really cold and can't get my draft under .05" WC with the baro.

There are other variables too. This year I'm burning red ash and this stuff has been very user friendly. The white ash I burned last year liked to flash at me occasionally lol.

In a nutshell, its important to have a fair amount of fresh air coming in over the fire after loading. After that, its important to have a much much smaller amount of air coming in over the fire. I think if you apply this to your shake and re load ritual, you will fix your puff back issue

tony17112acst · Post by **tony17112acst** » Sun. Dec. 16, 2012 5:47 pm

Update:

Good News Everyone ...I think I found my fundamental problem:

I have found that I'm getting good blue flames when I liven the fire up twice as much as I was. I always did liven up the fire, and knew to do so from all of the posts in here. But it turns out that I wasn't doing it enough. I'm getting great results now. I'm also not adding a full load all at once. This helps season the new coal and allows me to add the rest of the full load about 15 minutes later which is giving me good blue flames consistantly.

Again, for anyone having trouble wit this, get some really strong flames and you'll have very good results getting those blue flames.

Thanks to everyone who gave me all their examples and theory of the puffback!

-Tony (puffback free for 2 weeks)

Post by **Lightning** » Sun. Dec. 16, 2012 6:14 pm

tony17112acst wrote:Thanks to everyone who gave me all their examples and theory of the puffback!

-Tony (puffback free for 2 weeks)

Very good partner! Thanks for the update, glad to hear you are making progress!!

TLC2000 Explosion Blew Apart Stove Pipe, Door Latch Bent up

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