TLC2000 Explosion Blew Apart Stove Pipe, Door Latch Bent Up

I would also use the one piece elbows, not the adjustable type. They are weak in this type of situation.

Hey Tony, coal burning has a lot of trial and error and you will also discover a technique that works for you.. Everyone has their own process and their own reasoning for how they do it. I can't say that anyone's technique is wrong, since it works for them.. Same as no one can say my method is wrong, since it works for me. There is some art involved with the science, which makes burning coal fun and exciting. All you can do is try and understand the methods and their reasoning, and try to apply that knowledge to your own shake down and re load ritual until you find a method that works for you.

Some people load in layers. (The only time I use the layer method is with starting a new fire from scratch.) Some people bank to one side, or bank front to back. (I always level and mound in the middle, covering the burning coal completely.) Some people don't have the ash pan door open as a way to rev up the fire when fresh coal is on top of it. They open the air feeds instead.

All of these methods keep down the formation of volatile gases. I must agree that my method promotes more volatile gases to form. My way to deal with this is simply to keep them diluted by keeping the load door cracked open and the manual damper wide open.

Keep us posted with your progress partner

oops double post

tony17112acst wrote:OMG, NOW we're getting somewhere!!


I have learned everything else I think I need to know otherwise:
* Leave a red glowing corner when loading;
* Never close the load door without seeing blue flames;
* If you have a low fire with very little coal, add smaller amounts, not one huge load;
* Puffbacks are more likely to occur on a warm day;
* Running fresh air at full blast will cause a puffback since the draft is too strong, not allowing the gasses to ignite.

I think you are on your way to trying a few things to dial in your very own customized procedure that will work in your set up. As stated, the blue flames being present show the gas being burned off. How you get to that point when reloading will vary a little based on the level of your coal fire when you started, outside temps, your draft, your stove's personality, your coal, etc, etc. It will take a little trial and error on your set up to figure out your procedure.

The following is the procedure I used on my set up that kept me from having puff backs when running my handfired, I would say leaving the corner exposed and livening up a low fire were most important and would suggest you start from there...

Always, always, always leave a corner of red glowing coals to ignite any gas ( did i mention to always do this?? )

Get a low level fire "livened up" prior to loading - I did this by opening the ash door and leaving the loading door shut for a few minutes prior to loading (usually around 5 minutes) - dont forget, carry a timer around with you.

Leave the ash door open for a few minutes after loading up with that corner of red coals exposed (usually no more than 5 minutes - carry the timer) - loading door is shut during this time. When it was ready for the next step, I could see some quick blue flames immediately around the exposed corner.

With ash door still open, carefully crack the loading door open providing over fire air and slowing air through the coal bed, blue flames roll over coal bed igniting gas, close the ash door after blue flames ignite that gas and then close the loading door. If blue flames remain you are done. If blue flames go away, then it wasn't quite ready and I would close loading door and open ash door to rev it up a little longer - maybe a minute.

Then I would repeat the cracking of the loading door step until I got the blue flames to remain.

The steps above worked for me, my stove had windows which allowed some over fire air even with the loading door shut, yours may be different. The particular load of coal I had on hand would vary in its volatility depending on size, how "clean" it was and which mine it came from. Outside temps also caused variability, if it was warmer, I would cap off my baro to increase draft to liven up the fire.

That is quite a "puff back" if it actually blew the pipes off and bent the loading door latch? It happens, but yours sounded like the culmination of "the perfect storm" of circumstances.

My Glenwood has over the fire, a secondary air damper. It actually has Gas Burner cast into the vent wheel. You can see the vent in my avatar pix. Even when this is closed completely, it still has some openings. They knew, way back then in 1907, that people would probably forget to open that secondary vent after a fresh load so they tried made it idiot proof for lack of a better description. . That is the key my friend, as I know you've heard many times by now. Open the MPD. Make it a point to do this every time before you touch the stove for any reason. If you have no secondary over the fire air then crack the door or rather leave it cracked open after a load. Try to leave it some flame if possible too. You'll get the hang of it if you haven't already. Just remember the old combustion rules about air and you'll be fine.

the most important suggestion from all this good wisdom is to leave that RED spot when reloading...after it gets going good blue flame every where then cover the red spot and keep an eye on it for a little while...RED SPOT...never completely cover the whole thing with fresh coal when reloading ...LEAVE A 4 OR 5 INCH DIAMETER...RED SPOT...

Does the TLC 2000 have two air openings on the sides up top that are used for burning wood ? Why not open these when refueling to give over the fire air . This should give the same result as opening the top glass door. Then when shes burning good you can close them.

buck24 wrote:Does the TLC 2000 have two air openings on the sides up top that are used for burning wood ? Why not open these when refueling to give over the fire air . This should give the same result as opening the top glass door. Then when shes burning good you can close them.

If this is the case, excellent suggestion OR when she's burning good almost close them and leave a tiny bit coming in over to burn off volatile gases or to keep them diluted so they can't flash.

This may also help you. If your not sure of yourself load one layer at a time keeping the blue ladies going or or red hot coals showing until full. Once its full and you have the blue ladies bring the stack temperature up to 175º then close it all up and set your primary where you want it. You can also open the secondary air fully on both sides instead of leaving the door cracked. Just don't forget to close them. Although they are never fully closed because that is where you get the air wash for the glass.
You can also bend the latch on the stove back in with a big pair of pliers.

What is a normal stack temperature for the Harman TLC2000?

In addition to my other post, I forgot to mention that coal quality will have a large effect on explosion tendencies, in addition to the lack of flame. When I burned bituminous once, it was hard NOT to get an explosion of some sort. The biggest explosion I ever had was while burning bit. Cracked my glass in 2 pieces!

" would it be a rule of thumb that it's safe only when you see blue flames while the load door is open and you CONTINUE to see them steadily after closing it? ...because my blue flames went out when closing the door"

Yes the blue flames have to be there when the door is closed. Opening the door is the same thing as closing down the ash door vent. It slows the rush of air through the coal bed. The next time you get the situation of the blue flames igniting when you open the door and going out when you close it, try closing down the the ash door vent a little bit and see if the blue flames remain with the loading door closed. A quick look opening the door can confirm this if there is no glass in the door to see.

Leaving a red spot exposed can certainly make it easier for the gas to find an ignition point but there is also plenty of red coals further down in the bed which can ignite the gas if only the rush of air through the bed is not so intense as to blow the gas away from the red coals.

Stoves with a thermostat are less prone to puff back because the thermostat senses the extra heat and closes down the air making the gas slow down enough to ignite before reaching dangerous proportions.

If you watch a welder with his oxy acetylene torch he first opens the acetylene and lights it. A long yellow white flame results from particles of carbon precipitating out of the gas and burning. He next opens the oxygen valve and the flame suddenly turns blue because the oxygen is being mixed with the acetylene gas before burning, but what will happen if he continues to add more oxygen pressure. The flame will be blown out despite ideal fuel and oxygen. So to burn right gasses have to have the right proportions of air at a velocity they can use.

The next gas in a coal fire is carbon monoxide which is caused by not having enough air in parts of the coal bed. The carbon does not burn completely. We can't just add air through the bed because the rest of the fire will get too hot, so this is where a little over fire air will help to burn it in a well established fire. Those blue flames you see in a well established fire after the initial gasses are long gone are carbon monoxide burning.

tony17112acst wrote:....... would it be a rule of thumb that it's safe only when you see blue flames while the load door is open and you CONTINUE to see them steadily after closing it? ...because my blue flames went out when closing the door. ...

Yep - that's why I said : CLOSE ASH DOOR FIRST, THEN close loading door.

To quote myself:

SMITTY wrote:DON'T leave the glass door open. To avoid this in the future is very simple -- if you see no blue flames, THEN you should open the MPD, and CAREFULLY and slowly open the glass door. Usually the crosswind will get the flames to appear, at which time you close ash door FIRST, then glass door, so as to not extinguish them. IF you still don't see flame, I've had luck blowing on the top of the fire - could use a bellows for that - would be a bit safer.

Good call smitty ...thanks. I leave my manual damper open at 45 degrees at all times; is that OK? I feel like the air intake determines the air going up the chimney.

Also, I think I'll try the side vents which are on this TLC2000 to help bring on the blue flames.

I think loading too much coal at once was the main culprit plus having the ash door open. Observing the blue flames go out after closing the door should have been my red flag.

-Tony

Doesn't anyone read the 'sticky notes' at the top of each forum page ??

Here is a whole thread on the 'puff backs' aka 'minor explosion'

Minor Explosion In Coal Stove

BTW, I've blown the pipes off of my hand fed boiler in the past, so I have plenty of experience with 'puff backs'.

Anything that allows the fresh coal to 'cook' without either good draft and airflow up the chimney [like a closed MPD]
or a closed down stove will allow a lot of volitiles to collect in the firebox, and once a flame makes it's way through the
coal bed, the it will ignite,,, explosively.

So, leave a 'pilot light' aka red coals exposed to ignite the volitiles, or load in small batches, leave the MPD open,
or make sure you liven up the fire before loading, and supply plenty of airflow over the fire.

Hope this helps,
Greg L

I don't have time to read through all 3 pages of responses, but I will tell you how I do it, and I am a newbie as well. Burned wood my whole life, then went to soft coal, this year is the first year of hard coal.

I start a fire with paper, cardboard, sticks, and 3-4 pieces of wood. This gets the house warming up fast and provides a nice hot bed of coals. After that, I turn off the blower, open the double doors, and lay down about a 2" layer of coal. I dont cover all of the hot wood coals, I leave some gaps, then open the ash pan door a little. It flares up almost immediately. I let it go for a few minutes until there is a good fire going, then open it up and lay another couple inches down of coal, close the doors, and crack the ash pan door again for a couple minutes. I continue this cycle until I am at the top of the firebricks and there is visible blue flame burning through the whole thing. Then I shut down the ash door and slide the vents to about 1/4" and watch it for a while to make sure it all caught. If I notice it going dark at all, I crack the ash door just a bit to flare it up again and that usually is enough to make sure the whole 40 pounds or so of coal has burned off it's gases and is ready for a 24 hour run. When it is time to fill it back up, I place 3-4 pieces of wood on the coal bed, shake the grates and all of the old coal out, then wait an hour or so for the wood to burn back down to a hot bed of wood coals on top of the then layer of coal that was left after shaking. Then I refill again as above.

No explosions yet (had one last year with the soft coal but it was minor) and no CO detectors going off yet. Knock on wood!