I started a chimney fire

[Bspring]

I had been keeping an eye on my chimney and knew it was time to clean it. My furnace will smolder when it gets to the temperature that it is set to so I have to clean it often. I was waiting for a day when I had some time and was not too cold. It was 27 this morning but would be in the 50s in the afternoon so this was the day. I went down to the basement to get everything together and saw that there were a few small logs still smoldering from the morning fire. They were only about 2" in diameter and mostly coals so I tuned the forced air on full to blast them away while I went upstairs to put some coveralls on. That was not a smart move! When I came back down heat was boiling off the stove pipe and I could hear it crackling. I cut off all the air and ran outside to check the roof. There was a lot of smoke for a while and then it stopped smoking and there was just a small flame around the outside edge of the cap. I thought I saw a few drops fall to the roof. When every thing cooled down I puled the clean off cap where the stove pipe goes into the insulated pipe and the insulated pipe was as clean as new but the stove pipe was still dirty. This makes me think that it started at the top and burned down. When I cut the air supply it must have died before it got to the stove pipe. Anyway, I will not be doing that again.

 

[jeffesonm]

that's one way to clean it out

 

[LocustPocust]

I think we've all been there. Raises your blood pressure huh?

 

[STIHLY DAN]

Time for a better/cleaner furnace. That should never happen.

 

[blades]

Might want to investigate the moisture content of your fuel as well.

 

[billb3]

Did a clean out yesterday.
( a little overdue, yeah, yeah, yeah )
After the first year with this 1.9 cu ft stove we had almost two gallons of build up in the chimney. The wood is extremely well seasoned so figured we were running too long smoldering on the last half of a burn with the stove temps too low so last year never tried to get the air in at almost zero keeping the stove in the "safe" zone as long as possible instead of trying for long burn times.
One cup yesterday.

 

[baseroom]

With this weird warm weather we have been having it is making me think very carefully about burn rates etc. It is indeed challenging. Glad you are safe!

 

[CentralVAWoodHeat]

With warm weather like this I will almost always just kindle a few hot fires a day rather than load the stove and shut it down for a long, cool burn time. It is definitely a bit more work but I can literally got years without cleaning my chimney. Last year we put 7 cords through the stove and my pipe was clean as a whistle. Severl hot fires will always be better long term than the long, slow, cool, dirty burn, even with dry wood.

 

[Bspring]

With warm weather like this I will almost always just kindle a few hot fires a day rather than load the stove and shut it down for a long, cool burn time. It is definitely a bit more work but I can literally got years without cleaning my chimney. Last year we put 7 cords through the stove and my pipe was clean as a whistle. Severl hot fires will always be better long term than the long, slow, cool, dirty burn, even with dry wood.

This is true and I use this method with my stove at my shop. I could also have cleaner burns with my furnace if I were willing to use it more like a stove. However, I like the ability to load it up and when the house gets to what ever temperature I set the thermostat to, it chokes the fire down. Several hours later if the temperature drops down the blower kicks on and I have heat again blowing through my ductwork. This allows me to wake up to a warm house using pine. I will have to shift to oak if it gets really cold. The down side is I have to clean my chimney 3 times a year. I could have gone longer this time but I turned the blower on full blast. The automatic setting that I use is about 2% of that.

 

[CentralVAWoodHeat]

This is true and I use this method with my stove at my shop. I could also have cleaner burns with my furnace if I were willing to use it more like a stove. However, I like the ability to load it up and when the house gets to what ever temperature I set the thermostat to, it chokes the fire down. Several hours later if the temperature drops down the blower kicks on and I have heat again blowing through my ductwork. This allows me to wake up to a warm house using pine. I will have to shift to oak if it gets really cold. The down side is I have to clean my chimney 3 times a year. I could have gone longer this time but I turned the blower on full blast. The automatic setting that I use is about 2% of that.

This week is supposed to be in the 60's and 70's here and is making me jealous of that feature on your furnace.

 

[Pennsyltucky Chris]

Accidents happen. You tried to do the right thing, sometimes we make mistakes.

Bottom line: You and your family and your house are safe. Merry Christmas.

 

[LocustPocust]

With this weird warm weather we have been having it is making me think very carefully about burn rates etc. It is indeed challenging. Glad you are safe!

It's frustrating. It's too warm for a fire, but it's too cool not to have one.. So you either freeze or start a fire and then you're baking within a half hour. I try to burn my stove hot and clean as much as I can and it really cranks out the heat.. not helpful when it's 45 degrees outside and it doesn't even really cool off at night. I've had the windows and doors open a lot this fall with the stove going and I'm loving the fresh air.

 

[brenndatomu]

I see you have a Big Jack furnace...I had one of those...yup, they are pretty good at crappin a chimney up! I came up with some pretty simple mods on mine that helped clean things up and increased heat output too. I'd be happy to share if you are interested in doing a few quick and non permanent mods.
I'm sure you know already, but good dry wood helps a lot too...
Do you have a baro on the stove pipe?

 

[Bspring]

I see you have a Big Jack furnace...I had one of those...yup, they are pretty good at crappin a chimney up! I came up with some pretty simple mods on mine that helped clean things up and increased heat output too. I'd be happy to share if you are interested in doing a few quick and non permanent mods.
I'm sure you know already, but good dry wood helps a lot too...
Do you have a baro on the stove pipe?

I am always open to new ideas. Most of what I know about wood burning came from here. My wood is css and covered for 3 years. Yes I have a baro on the stove pipe with a manometer mounted on the wall next to it to check the draft.

 

[brenndatomu]

I am always open to new ideas. Most of what I know about wood burning came from here. My wood is css and covered for 3 years. Yes I have a baro on the stove pipe with a manometer mounted on the wall next to it to check the draft.

Good deal on the baro and manometer.
OK, here is what I did to my Yukon Big Jack.
Get some ceramic insulation blanket like they use on chimney liners, 1/2" works well. (you could use Roxul too, it can be found at Lowes or HD (and others?) Stuff that in the air slot that runs down the sides of the firebox, right above where firebricks sit. Plug off the whole slot, except the back 4-6" or so.
Get a piece of sheet metal (1/8" to 1/4" is fine) big enough to cover the grates, all but the back 6" or so. Then you let 2-3" of ashes (at least) build up on the plate, that will be the new normal. You can still push ashes through the grate in the back, and the nice thick ash bed on the plate holds coals well, which can be shoved to the back where they can get plenty of air on reloads...that makes for easy relights. The wood will now tend to burn rear-to-front, instead of front-to-rear like before. If you think about it, this makes more sense, the wood is out-gassing (smoking) mainly in the early part of the burn, so that is when you need good secondary burn action to keep the chimney clean. Good sustainable secondary burn is accomplished much easier in the back, especially now, since this is where the fresh (and now somewhat preheated) air comes in after doing these mods.
Once the wood gets to the coals stage there is no more smoke, only clean burning.
What these two mods accomplish is to only allow air to the back of the firebox, where you are well back under the baffle plates, you can get, and keep, secondary burn going much better back there. Speaking of the baffles, the factory steel ones work OK, but if you switch them out for 1" thick ceramic insulation board, cut to roughly the same size as the factory plates, it seems to keep the secondary burn going hotter/longer. I bought my board from skylinecomponents on ebay. And the 1/2" ceramic insulation blanket that I used was left over from one of my chimney re-lines.
FYI, I had installed a small glass (actually high temp ceramic) viewing port in the door so I could actually see what was going on in there. The factory secondary air system is a joke and works poorly unless you are on high fire (combustion blower running and/or air intake wide open) with a fresh load of wood. Things worked MUCH better after my mods...hotter, for longer, and cleaner. The inside of the firebox went from black, brown, and tan soot, to mainly tan and white soot.
Bottom line, flip your fire! Primary fire and secondary burn in the back, red hot coals in the front, it works out much better!
Hopefully this isn't too confusing, feel free to ask questions if it is. Happy heating! (and Merry Christmas ya'll!)

 

[brenndatomu]

Oh, and doing this ^^^ will probably change how you run the unit. After loading you will want to open up the air some and run the combustion blower to get the firebox good and hot. Once things are rolling good you can shut the blower off, let things settle down for a couple minutes, you can then begin to cut the air door on the blower down. The firebox temp will actually go up (and stay up for quite a while) when you cut the air back (slowly), that secondary fire makes a ton of heat! The goal is to cut the air back enough to get a nice long burn, but, still have enough air to keep that super hot (and clean burning) secondary flames going. Controlling the house temp will be more dependent on the size of the wood load that you put in, more so than it was before anyways. With a little practice you will figure out the new sweet spot(s).
And just as with the modern "EPA" fireboxes, this all works the best with truly dry wood. The nice thing is that if your wood is just so-so dry, your Yook will still burn it, you just lose the nice long hot secondary burns (similar to what you have now) But the "EPA" fireboxes almost won't even burn wettish wood, (at least not with out a ton of screwing around with it) so you are still ahead of the game there.

 

[Seasoned Oak]

After 8 years of burning 4 EPA stoves and 3 NON -EPA stoves in various locations i can say iv never had a chimney fire (that i know of). I always burn dry wood and try to burn the stove hot not letting it smolder. Its those smoldering cool fires that cause the problems IMO. Every time i check the chimneys in various locations they are always clean.

 

[Bspring]

brenndatomu: these mods sound like something that I can handle and would like to try. Can you tell us more about the door mod. I would really like a window. As you said you could tell how the secondary burn was working.

 

[brenndatomu]

I don't remember exact sizes any more, but it should be pretty easy to figure out.
Unbolt the door and take it to the shop.
I cut a hole in the center of the door, just low enough to be able to see under the smoke flapper (arm burner) using a properly sized hole saw. FYI, the door is double wall and the insulation in the middle should be removed before cutting the hole, you will put it back in later. (IIRC) You can just unbolt the inner part of the door to remove insulation, then put the inner wall back in place before drilling the hole. I cut off a (again, IIRC) 1.5" pipe (conduit) nipple just long enough so that the cut end sticks through the inner wall 1/4" or so, enough to run a bead of weld around it, and the outer threaded end sticks through the outside enough to thread on a 1.5" pipe (conduit) coupling to it's seated position. I used a MIG for the weld. Oh, and don't weld the outer panel, it needs to float with heating and cooling cycles expansion/contraction.
I think I ended up using conduit parts, because the threads fit looser, and are easier to work with here.
Anyways, the leftover end of the nipple that was cut off earlier should have threads on one end. Cut the first 3 or 4 threads off of that, try to make it straight/flat because this will be then "nut" that holds your glass in. After it is cut and deburred, cut 4 or 6 slots in it on the surface that was just cut off, so that you can use a screwdriver or two to thread it into the coupling.

I had the local glass shop cut me a couple (in case I broke one...and I did) pieces of round high temp ceramic 1/8" glass so that it will sit loosely inside the coupling, against the end of the pipe nipple. The "nut" that you just made will now be threaded into the coupling to hold the glass in place. Do not tighten much at all, the glass breaks easily when the metal touches it. I ended up cutting some high temp gasket "rings" so that the glass didn't directly contact metal, and it sealed better too.
I used a light coat of nickel anti seize on the threads so that I could get the nut in/out easily.
The glass got crapped up pretty quickly (pre firebox mods) so I make an "airwash" system for the glass.
Very carefully measure exactly where the inside of the glass comes to. Remove the glass. Drill (8) 1/8" holes around the coupling so that they come out just on the very inside edge of the glass. I angled the holes (outside to inside) toward the firebox a bit too. Instant "airwash", it works pretty darn well too. Maybe hafta take the glass out to clean it once a month or so.
This is the same basic design of the viewing port on out gas boiler at work.

I also considered (but never did it) making a swinging cover for the inside of the port. Metal teardrop shaped piece hanging from a 1/4" rod that comes through the door above the port. Some type of "handle" on the outer end rod. Loose enough that it can be turned up for a peek, then let it swing down to cover the port.

Hopefully this all makes sense...this isn't as nice as a full glass door, but does give you a view of the fire.
I'll try to find a pic...found one. This is the exact same viewing port setup, but on my Yukon Husky door instead of the BJ door.
Oh, and if you do the above firebox mods, you will run with the "secondary air" knob on the door in the closed position mainly.

 

[Bspring]

I'm at work so I think I need to read the post on the glass a few more times. This looks like a summer time project for me but I think I will be able to make it work. Thank you for sharing it with us. It might have been better for this to have been in its own post for other BJ owners. I may start a post when I get it done and give you credit for it. Thank you for sharing all your R&D with us.