What defines a Runaway Stove?

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Phoenix Hatchling

Phoenix Hatchling

Minister of Fire
Dec 26, 2012
713
New Fairfield, CT
Was curious if this refered to an uncontrollable blaze shooting up, over and out past the top baffle, or simply a fire which is too hot for the stove and in danger of an overfire? It seems that one goes hand in hand, but the blaze seems to be the dangerous portion. Or do I have it wrong?
 
Hard to say since we can't see what's going up the flue. I would guess that if you see 900+ on the flue temp, you have flame in there. Either way it will scare the bejeezus out of you...been there done that and it was all my fault.

"Dumedubedum, yawn...it's late, I think I'll throw one more stick in before I go to bed"[stove flue at 500]......creak... open door......and before I could stick the stick in there I thought I was on the flight deck of an aircraft carrier standing behind an F4 in full launch throttle. I slammed the door shut, but the digital monitor looked like the national debt ticker, things were popping and tinking even after I shut down the primary air, so I stuffed a fireplace glove into the secondary air tube and things still looked, felt, heard hopeless. Looking back I should have gone outside to see what was coming out of my 25' 8" flue, but maybe it's good I didn't, I might have gone into de-fib. It reached almost 1,000 before it started dropping, and the thing(my heart) made a lot of noise for the next hours as things cooled.
 
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Motor7 Described it spot on. Stove temp climbing rapidly with no control.

Causes are many but most relate to heavy amounts of fuel off gassing to rapidly to control. Loading onto a large bed of coals in a hot(400+ stove), leaving primary air open too long or door cracked to long or the dreaded ash pan open during start up. Most times, but not always, an over fire is from any or more of the above coupled with "getting busy w something else and walking away" OOPS!! I forgot!!

Some use a timer set at 10min or so intervals to keep them safe as they get going in the AM helping kids, making coffee, etc. Not a bad idea to tape a note at the door to check the stove before heading off to work and maybe a "last light switch" note that you hit before bed - or any other place you feel necessary. Better to be safe.....

Do a search on the many ways to slow a run away down including actually adding air to let the heat go up and not build inside the box. Cutting off as much air as possible with the glove or a pre-made ball of foil on the primary and covering and other air holes on your particular stove. I have a tin foil ball ready and flat magnets for smaller holes near the stove. Never had the 30 go off but again best to be prepared for the worst and expect the best.

For the record, anytime you have a load of fuel in the stove and it is in the beginning stages of a burn you will have blow by flames going around the front - if not you are burning to low. This does not signify a run away.
 
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Sometimes you do all the right things and you still get a nuclear inferno. I have 25' of chimney/stove pipe and very good draft. Occasionally, and it seems impossible to predict when it is going to happen, I get a waaaaaaaay hotter stove than I intended due to crazy secondaries.

Last night like many other nights I wanted to load up the stove full and have a good overnight burn as it was going to be in the single digits and windy here. I put about 6-7 good sized splits on a good coal base in a 250 degree stove.

I always reduce air as early as possible and try to stay ahead of the fire. I reduce air judging by the way the fire looks, not a flue or stove top temp. Anyways, after about 15 minutes I had reduced the air almost all the way and had active secondaries. The stove top was about 400 and the flue was about 400 (probe). Ideally at this point temps would continue to raise to about 500/500 and settle in.

NOT LAST NIGHT. (And many other fires). I could tell that it was going to be a hotter fire than I intended. At the 20 minute mark the secondaries were really starting to roll aggressively and the stove and flue temp were rising quickly. I reduced what was left of the air control, maybe 5% of its total travel. Enter nuclear secondaries.

With the air shut completely off the secondaries where in control. The coals and wood were dark as no air was being fed to them. The secondaries were running the show. After a couple of minutes the flue temp was 900 and the stove top was 850. No choice now but to but the blower on high and wait it out.

What is happening is excessive draft. The chimney wants to pull more air but the main air intake is shut down. It starts to pull the draft it wants though the secondary air inlet. This aggressively fuels the secondaries and off they go. One solution to this problem in a runaway situation is to put a magnet over the secondary air inlet if you have access to it.

FWIW.....even though the secondary light show looked like the inside of a nuclear mushroom cloud and I had 900 degree flue temps.....no flames were going over the baffle board.
 
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I have yet to experience this and from what I hear it certainly is a white knuckler! I have flames often going up and passing over the baffles and blanket. I don't know how far back they actually extend, but I suppose this is normal practice. With my stove being an insert, I don't have access to the air intakes to block them off. What's more, it appears that even when I have the air closed all the way down, it can still build and grow in size. This is the result of the draft caused by the fire itself? It would be nice to know what to do, when the day comes that I have my brain fart and do something such as listed above.
 
I'll never forget when we installed the Fireview. We loved the stove. Then one night it got cold so we loaded it up. It was so enjoyable watching the fire and enjoying the heat. Then it was like the flames simply lifted right off the wood and went to the top of the firebox. Then it started this rolling that was really fantastic to watch. Naturally, when it started to get a bit warm, I looked at the temperature gauge on top of the stove. Whoops. Recommendation for this stove is a maximum of 700 degrees. At that time it was 650 and still climbing. By the time it got to 680 I was getting pretty nervous and started to make some plans or at least try to think of something good to do to calm this thing down. But the temperature stopped going up at either 680 or 690. What a relief!!!! Now we simply enjoy the show and the heat.

But a runaway stove is a very scary thing.....and rightly so. People should know ahead of time what they are going to do. We have lots of sand, like beach sand so we know we can simply throw some sand in the firebox if need be. Ashes will work too. But I guarantee you that opening a firebox door when the stove is going berserk is in itself very scary too. Work fast.
 
BurnIt13 said:
Sometimes you do all the right things and you still get a nuclear inferno. I have 25' of chimney/stove pipe and very good draft.
NOT LAST NIGHT. (And many other fires). I could tell that it was going to be a hotter fire than I intended. At the 20 minute mark the secondaries were really starting to roll aggressively and the stove and flue temp were rising quickly. I reduced what was left of the air control, maybe 5% of its total travel. Enter nuclear secondaries....


....What is happening is excessive draft. The chimney wants to pull more air but the main air intake is shut down. It starts to pull the draft it wants though the secondary air inlet. This aggressively fuels the secondaries and off they go. One solution to this problem in a runaway situation is to put a magnet over the secondary air inlet if you have access to it.

..
Click to expand...

Question then: If abundance of draft is a contributor to a runaway stove, then would adding a flue damper help for those situations?

If there was a damper installed, it could be left "open" during everyday normal use. But then if REALLY needed, it could be "closed" to cut back on any over draft.:confused: ???? I don't know, just asking.
 
Motor7 said:
Hard to say since we can't see what's going up the flue. I would guess that if you see 900+ on the flue temp, you have flame in there. Either way it will scare the bejeezus out of you...been there done that and it was all my fault.

"Dumedubedum, yawn...it's late, I think I'll throw one more stick in before I go to bed"[stove flue at 500]......creak... open door......and before I could stick the stick in there I thought I was on the flight deck of an aircraft carrier standing behind an F4 in full launch throttle. I slammed the door shut, but the digital monitor looked like the national debt ticker, things were popping and tinking even after I shut down the primary air, so I stuffed a fireplace glove into the secondary air tube and things still looked, felt, heard hopeless. Looking back I should have gone outside to see what was coming out of my 25' 8" flue, but maybe it's good I didn't, I might have gone into de-fib. It reached almost 1,000 before it started dropping, and the thing(my heart) made a lot of noise for the next hours as things cooled.
Click to expand...
Lol. Great post.
 
My runaway was all my fault left the primary air open too long, stove top started to glow red, I opened the door to try to cool it down , all this did was force the hot air up the liner that I can see through that brass grate in my avatar, the liner started glowing red. Shut the door pushed the primary air in to close and put a box fan on high blowing on the insert and after alittle while things calmed down. Then I had to change my drawers and gab a beer and sit there scared chitless.
 
beer was not adequate for this situation......Cuervo straight, and lot's of it right outta the bottle.............just thinking about it makes me reach for it....ok, maybe I already had some tonight
gfdgdey20.gif
 
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Mine last year came from the vacuum cleaner. Knowing that the 30 on the first floor has massive draft I had blocked off 1/3 of the secondary air and it became a dream to burn in. Vacuumed the fireplace and up around the blower in the back and was good go and lit it back up.

Packed the night load after establishing a coal bed and, long story short, right up to a thousand degrees. Realized while it was in progress and grabbed a flashlight and mirror and saw that magnet that should be on the secondary port pushed aside by the vacuum cleaner nozzle. :mad:

Couple of nasty hours followed.
 
I just loaded up for an overnight burn and began to read this thread .My insert is installed in a fireplace that use to have a blower system on it. I can peek through the vent in the bricks (above stove, but under mantel) and see that my flex liner has a faint red glow to it. Is this dangerous? Stove temp is currently at 500. I've now dialed back the air about halfway and the red glow went away quickly. Am i pushing the stove too hard on reloads?
 
Elusive, I doubt 500 is a concern, but I dont have a insert. My stove runs in that temp range quite frequently, nothing glows, but since yours is inside a hearth you are capturing a lot of heat there....might be normal.
 
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Elusive said:
I just loaded up for an overnight burn and began to read this thread .My insert is installed in a fireplace that use to have a blower system on it. I can peek through the vent in the bricks (above stove, but under mantel) and see that my flex liner has a faint red glow to it. Is this dangerous? Stove temp is currently at 500. I've now dialed back the air about halfway and the red glow went away quickly. Am i pushing the stove too hard on reloads?
Click to expand...
I don't think that's normal , weird thing is 500 is not that hot , tells me your sending a lot of heat up the chimney. Mine has only glowed once on that faithful night and so was my stove

Re-read your post wide open your sending a ton of heat out of the chimney dial her back sooner , glowing liners is not good.
 
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