Closest to over-fire I want to come!

[Sconnie Burner]

Running a Quad 3100 step-top, stove top was at 250 with smallish coals. I loaded it up for overnight with 2 chunks of boxelder and 3 chunks of oak I call over nighters (bigger full length slits) with a few smaller, gap filler splits, filling the box to just below the tubes and stepped the air down as usual. Maybe a little faster than normal. Walked away for 15 mins or so and came back to the Stove top at almost 800. With secondaries going crazy and the flames on the logs were not lazy they were actually rolling around pretty good as well! I Turned the blower on HIGH which kept it at 750. Still didnt like what i was seeing and took the side cover off and blocked the air inlet by the burn rate lever and also stuffed some ceramic blanket in the secondary tube's intake hole. Then it settled down drastically with very minimal air. I then removed the stuff and it burned fine. The wood was just really burnt up.

What did I do wrong to cause this to happen? Too much wood? Really dry wood? (Very low teens 10-11% mc 8 yr old oak and elm) Or do I have a possible over draft with 22 ft of chimney? This is the first time its gotten that far out of control and I don't want to see that happen again.
I tested the door seal and glass seal with a lighter flame as the fire continued burning and didnt notice any spots that sucked the flame in.

 

[Sconnie Burner]

Surface flue temps only reached 400.

 

[Sconnie Burner]

One more question. I have read that opening the primary helps. I did try that briefly and didnt notice a change. But how long should I try that before I did what I did?

 

[northwinds]

Sounds like you stayed under 800. No worries, although it's better to stay under 700.

Did you rake the coals completely forward before reloading?

Could also be dryer wood than usual. Also, those smaller fill-in splits probably helped feed the big ones. I had some really dry oak last night (ten years split from an old farmer nearby) so I shut it down quite a bit faster than normal. Settled down just under 700.

I've never tried opening the primaries to slow it down. I have tried to open my doors wide to slow it down, but that didn't really help much. My stove has never really been out of control though and is pretty responsive to the air controls.

 

[HotCoals]

Could have just opened the door. The colder room air will usually calm it down and the strong draft gets broke.
The wood must have been really off gassing fast.

 

[begreen]

Walked away for 15 mins or so and came back to the Stove top at almost 800. With secondaries going crazy and the flames on the logs were not lazy they were actually rolling around pretty good as well!
What did I do wrong to cause this to happen?

You said it in your first sentence. You walked away too long. 15 minutes was too long. The stove should have been turned down much sooner. Stay by the stove next time or bring a timer with you and set it for 5 or 7 minutes.

 

[DougA]

begreen ++++

That's why I like the digital thermometer. I have it set to scream at me when I leave it too long. 15 min would normally be fine, just not in this case.

 

[Sconnie Burner]

You said it in your first sentence. You walked away too long. 15 minutes was too long. The stove should have been turned down much sooner. Stay by the stove next time or bring a timer with you and set it for 5 or 7 minutes.

I had every control shut down at 450ish as far as they would close at the point I left the stove. I returned to check hiw it was doing and was shocked it got away lime that. I would suspect fast off gassing was the problem. Did it raise the flew temp causing the draft to increase to rapidly? Its just wierd there isn't a way to shut it down more. Us rookies could use a full close option for this very instance.

 

[Nick Mystic]

This is a timely post since I've been contemplating this very situation recently as I watch my fire at night after my final reload. I make a point of staying right in front of the stove after I reload so I can control my primary air according to what I'm seeing in the stove. I do this every night and I've learned there is no rule of thumb you can reliably go by on when to turn down your primary simply based on the passage of time. Each fire is more or less unique and you have to use your observations to lower the primary air properly. As I reduce my primary air as my fire burns more vigorously I eventually get down to my lowest setting. At this point many people would watch the for another few minutes and if things look okay they would head to bed. Since I enjoy watching the fire burn I often remain in the room watching the fire for a more extended period. What I've noticed is it is important to watch the fire for at least ten minutes after you make your final air adjustment. The fire might look just the way you want it after a few minutes, but my observations have shown me that it takes longer for that for the stove to react to the change in air input. Often, after ten minutes or so, the fire will start to grow too weak on my lowest setting, but sometimes it will recover and burn fine. Other times I have to open the primary slightly to get things back to where they should be. Being a top notch wood burner requires a fair amount of patience in my experience.

 

[northwinds]

I had every control shut down at 450ish as far as they would close at the point I left the stove. I returned to check hiw it was doing and was shocked it got away lime that. I would suspect fast off gassing was the problem. Did it raise the flew temp causing the draft to increase to rapidly? Its just wierd there isn't a way to shut it down more. Us rookies could use a full close option for this very instance.

You can put in a pipe damper for added control. You didn't answer my question though. Did you rake the coals forward before reload? If you don't, and you have coals dispersed through the firebox, everything is going to catch fire at the same time and involve the whole firebox (gates of hell syndrome). Also, we had cold weather last night. You will get increased draft as the temps fall to typical winter temps in Wisconsin. Have to compensate for that too. I had a damper for the first year that I owned the stove. I removed it after I developed confidence in how to control my stove.

 

[Sconnie Burner]

I pulled the largest ones forward but the whole bottom of the box still had a decent red glow with embers the size of peas to grapes. There wasn't any flames on the bottom or back of the fire box once closed down. But maybe the splits were burned enough that they were off gassing a lot? I thought the goal was to have them mostly charred by close down?

 

[BradleyW]

This is only my second season burning wood, so this is only a somewhat educated guess, but I wonder if the smaller pieces you put in to fill the gaps were part of the problem. In my limited experience those little pieces can really increase the temp of a fire for a short period of time. I add some small almost kindling-size pieces to the occasional fire that isn't hot enough, so it seems like they could lead to an overfire situation in certain conditions.

 

[Grisu]

With that kind of dry wood you need to be really careful. Try to move all the coals forward; if necessary burn them down a bit more. Also, if the stove and flue are hot try turning down the air a bit sooner and in stages to keep more control over the burn. You don't really need to wait until all the wood is charred. And if your draft is good, getting the air down to 3/4 to 1/2 just after a few minutes may settle down the stove enough to not have a runaway fire. Then you can close it fully once the fire is well established.

 

[Sconnie Burner]

That makes sense then. The drier wood than what I was used to burning and thinking it all needed to be charred was probably the issue. I tend to forget that the thermometers are probably a bit delayed as well. If it keeps becoming an issue I will possibly install a flie damper to get me out of that jam again. Its tough to block the intakes as I have to remove a side shield to do it.

 

[ddahlgren]

I think if you count on every split to be the same as the last is you are pulling your own leg.

 

[hamsey]

Timely post. I am trying to figure out how to control my fires better. Over the last two weeks I had a I had fires that are at the edge of my comfort zone (750 - 800). I started shutting it down earlier but the fire still climbs. I use to wait until 400 now I start at 300. I do get lots of off gassing. Air is shut all the way so I have no adjustment there. Only thing I can do is load less wood. I do not stuff it to the gills 4 or 5 splits. If I cut back to 3 or 4 I will get lousy burn times with no coals in the am to restart the fire. I do rake the coals forward not all but most. Guess I will try and get them all. Shut it down earlier before the wood is charred but don't I risk smoke? I know my wood is drier this year than last.

At what temperature do I not have to worry about flue gasses? 25' Interior chimney. Do you shut it down differently between the first fire and subsequent fires? Do I not have to worry about flue gasses after the first fire? Makes sense since the flue is warm but I do not want to assume anything. Just want to run this thing right. Bigger splits? Stuff I have now is on the smallish side. 2 to 3" new stuff seasoning is 3-5" 16" long.

 

[begreen]

With good dry wood and a vigorous fire started, you can cut down the air without worry about smoke. Secondary burn should increase. That will start burning excess smoke. Also, with dry wood and an interior chimney the risk of creosote build up goes down considerably with a modern stove. Bigger splits will definitely slow the fire down. I only use 2-3" splits for kindling. Most of my splits are in the 5-7" range with some 9 inchers in there. I use 4-5" splits as gap fillers. If you have to burn poorly seasoned wood then you must watch the flue carefully. Have it cleaned at least once for every cord burned. Damp wood cools down the fire and the flue temp considerably.

 

[hamsey]

With good dry wood and a vigorous fire started, you can cut down the air without worry about smoke. Secondary burn should increase. That will start burning excess smoke. Also, with dry wood and an interior chimney the risk of creosote build up goes down considerably with a modern stove. Bigger splits will definitely slow the fire down. I only use 2-3" splits for kindling. Most of my splits are in the 5-7" range with some 9 inchers in there. I use 4-5" splits as gap fillers. If you have to burn poorly seasoned wood then you must watch the flue carefully. Have it cleaned at least once for every cord burned. Damp wood cools down the fire and the flue temp considerably.

I thought you do not want to burn anything over 6". Believe I read that on woodheat.org site or their manual. I have a rather small firebox. Wood is seasoned properly this year. 16 to 19% on a fresh cut split. Last year we could not turn the air all the way down. This year yes and it continues to get hotter. Kindling 1/2 to 1" Guess I am still use to the open fireplace way of building a fire. Must admit that I am a bit nervous about bigger splits.

 

[begreen]

Not sure where that came from. I would only hold to that rule if the wood didn't have sufficient seasoning time, but that is fine if you want to burn 5-6" splits and no larger. Our firebox is larger and we are often burning softwood at this time of year. Our hardwood splits are more like 4-7". Bigger splits burn longer so there is no need to be nervous about them. Lots of small splits actually will make a much hotter fire because there is much more exposed surface area for the same volume of wood.

 

[ClintonH]

Good thread: I'm in the same boat. 2nd season with our Isle Royale and I will reload at ~250 degrees and IMMEDIATELY do full shutdown only to watch the temp climb up to 550 to 600. Secondaries are glowing red presently. I'm pretty sure my gaskets aren't worn out after 1 season, 4.5-5 cord last year. The only thing I can figure is my splits are smaller and they're drier than I've had in the past.

 

[BrotherBart]

When I do the night load in a half hour thirty minutes from then I will be looking a a 700 degree stove for a while until it settles down. Shut down, wide open, turned on its head or whatever. The charring burn on a large load is not for the timid.

 

[lopiliberty]

I filled the stove last night with chestnut oak and red oak. Raked the coals to the front loaded the stove. Started turning it down at 350 and 20 minutes later stove was at 750 blazing and I mean blazing secondary's red air tubes and the fan on low and that's where it stayed for some time not really sure how long because I went to bed. Guess that oak was drier than I thought

 

[Sconnie Burner]

I don't mind blazing secondaries at all. I just didnt like the flame being so intense on the wood itself. I have figured out a solution that has been working so far. Got a cow stomach rectangular magnet that covers up all but a sliver of the burn rate intake on my primary air. It had a limiter screw that seemed to be letting too much air in when the secondaries are going full bore. I can now dial the fire back to get the blue lazy flames everyone talks about while the tubes are blazing like mad. I haven't ever seen those lazy flames except when I close down too fast and then they disappear quickly. I am much more comfortable with the set up now. I can actully stop the stove temp from climbing uncontrollably.

 

[ddahlgren]

In my opinion the EPA made to stove more dangerous by not allowing the air to be fully closed down in order to protect idiots that are happy to let it smolder. My tiny Avalon hit 730 last night and was quite pleased with it to be honest. If it is a runaway but not a chimney fire why not just open the door to kill the draft and let plenty of air to dump the heat up the chimney?

 

[Sconnie Burner]

I've tried that and was nervous having the door open with an inferno in there. I have had embers come popping out past my already larger than necessary hearth and melt some carpet when trying to move wood back from touching the glass. Even with the door cracked a quarter open it seemed more like it was feeding the fire rather than slowing it down. The flames just rolled faster. Didn't want to open it farther for fear of embers flying out.