Can you really over fire a newer "modern" woodstove to the point of danger?

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MJFlores

Burning Hunk
Dec 22, 2013
185
NH
Hi all, this is just a reality check question and not meant for anyone to get careless as a result of the answers, or to fight with those of differing opinions. I'm very careful during the whole process of wood burning, and last night as I was getting the stove ready for a long burn until am I began wondering. Can you really over fire a stove?...and I mean really to the point of a dangerous melt down / house fire as a result? My gut says yes you can, but again are these stoves of ours able to handle far hotter temperatures than what we think they can? I know cast iron does have a melting point, and you can easily damage internal parts due to running a stove too hot but, has anyone heard of anyone having a house fire due to a stove melt down? I can honestly say I haven't. All the house fires I've heard of were a result of chimney fires, or careless disposal of ashes from the stove while cleaning. Part of me thinks that as long as the door is securely closed, and the air is cut back, you're at least safe from anything too crazy happening. My comfort burn range in my Fireview is 500 to 550...when it gets over 600 I begin to get a little worried, the very few times it got near 700 I was very worried and was turning the air down to nip it in the bud. It's funny how simple numbers of a 10 dollar stove top thermometer can make you get nervous....but is the nervousness really founded? Again, I'm asking,...in a modern woodstove with the door securely closed and the air cut back (not wide open) can an over fire happen that would result in catastrophic stove melt down? Has anyone ever experienced this first hand?
 
I can't fully answer your question, but I can tell you there is a wide gulf between 700f and burning down the house. I hit 700f on my stove on a regular basis, and have for years. So WRT to hitting 700f or so, I would say no, your nervousness is not really founded. (This of course assuming all clearances are met, etc.)
 
The wood you burn is going to have a big influence on how much heat you get out of your stove and I believe it is possible to over fire a modern EPA stove with the door properly shut. I was helping a neighbor clean out her garage one day and she had a pile of wood against an inside wall for her fireplace, which they had stopped using about 15 years earlier. She knew I burned wood and told me to take it. At the time I was new to burning (pre-epa stove) and my wood supply was all wet dead wood from the woods across the street from my house. When I loaded this super dry wood into my stove it got so hot my elbow out the rear of stove started glowing orange!

So, I would think if you loaded your stove with an abundance of very small super dry splits on a hot coal bed it could get into the over-firing range and cause trouble. However, I think the biggest danger would be due to a problem with flue pipe, fitting, etc, rather than the stove itself. Warped plates and internal damage aside the risk of burning your house down would more likely come from damage to the flue system, most likely involving some sort of chimney fire.
 
My understanding is that 'modern' stoves are designed to be safe within reason.

So if you are loading nothing but wood in there and were careless (leaving air open too far, whatever) then you may well destroy an expensive stove, but I suspect you would have a hard time actually setting your house on fire - again assuming all documented clearances and hearth requirements are met.

IF you have a bunch of build-up in your chimney then certainly that can ignite, but the chimney (if properly installed) should be able to contain one such event. Doesn't mean that sparks flying out the top (I've never seen it but hear it can look like a rocket out the top) won't set something (roof, trees) on fire....

So I'm with the "I don't worry about burning my house down" crowd - even when my wife or kids operate it. I am concerned that we could damage the stove if very careless - but even there I think there is a pretty high tolerance.
 
Your fireview can handle a stovetop of 700. Ive even gone over that a few times with our Oslo by mistake without any overfire damage. To answer your question, Id say heck yah you have to be careful or you risk burning the house down. If you happen to crack the stove or pipe, the flames are coming out. Id say this would be hard to do, but def not impossible. My biggest concern would be an out-of-control chimney fire. Im sure there are many families out there who have burned their house down with an EPA stove, Id be interested in asking them what happened.
 
With a soapstone stove my concern would be getting the stove so hot that a stone cracked. A stove in this regard is somewhat like a car. Drive it in the range it was designed for and all will be well. Drive it at its top speed and you will be stressing out the car and driver.
 
I've seen cracked cast iron caused by overfireing. I've also seen youtube videos where people have hooked up fans to force air into a stove made from barrels. I think you'd notice your stove was going to fail before it did. Maybe if you had a super tall chimney you could pull enough air into it to cause it to fail, but that's got to be a rare exception.

If one does fail, I'm pretty sure you'd be able to find the guy on youtube bragging on how hot he runs his stove.
 
guess it just depends on a lot of factors. Stoves have clearance to combustibles....but I don't know how it changes if your stove is over-firing for 2 hours and you have a glowing stove and stove top of 1400 or so.

700 is definitely getting into the over fire range but not the worst. I once forgot to check on the with the bypass damper open on my cat stove for 45 minutes. Stove top was over 800 and that was scary enough. I can't imagine what could happen if I actually left the house or went to bed and the stove was able to run away without my catching it for that long a time period.

I know the refractory would melt, at some point the cast iron could crack, but again I could easily see the stove creeping to 1400 degrees if left on its own for 120 minutes or so based on how hot it got after 45 minutes (usually it takes 15-25 minutes on reloads for the wood to catch and stove top to get to 500ish before I close it...so the stove only took another 20 minutes or so to creep past 800/850). I have a little kitchen timer next to the stove now for reloads.
 
Curious about the testing that the manufacturers perform. They must have to test for a meltdown limit.....it would make an intersting video...
 
I remember PE saying they ran a Summit wide open for something over 24 hrs just to see what would happen. Evidently not much.
 
I've always wondered about that possibility, too. A month/so ago I lit the Classic in my shop and then buried myself in a complicated foam layout... forgot all about the freshly started stove, with the door agape... . I was jerked back to reality by the roaring fire and blanched with fear when I saw the thermometer reading 700. I immediately closed the door, engaged the combustor, and turned down the air. Mouth dry I stood transfixed watching the thermometer... in a couple of minutes it began to go down (along with my blood pressure). Within 15 minutes it was right in the "comfy zone" and all was well. But it was a real "dope slap" for me... pay strict attention to the stove when starting a fire or bringing one back from a bed of coals. It's easy to get distracted and that's when bad things are most likely to happen.
 
I think really hot temperatures would put undue stress on the weakest link in your system, whatever that may be. Long as it holds up no problem. I have also read about parts stoves warping from to high of heat so that would be a concern as well.
 
It's an interesting topic. I think there is a big difference between having the air wide open, the door open etc. Running the door wide open I wouldn't expect much difference than burning in an open fireplace. The flames may roar do to the high amount of airflow entering the firebox, however with the door wide open most of that heat is going to go straight up the chimney and the danger is not going to be as much from stove meltdown/damage as it might be sparks, embers or whole logs exiting the stove through that wide open door.

On the other hand many times turning the air down actually increases the stove temperature because while you still supply plenty of air for combustion to take place you slow down the speed at which gases exit through the chimney making the stove actually hotter in that instance.

Somewhere in the middle there is probably a worst case senario for each individual stove in terms of air supply to combustion rate to chimney draft that will result in the hottest temperatures and if operated in that state continuously for long enough then more catestrophic things might happen.

End thought, be careful.
 
if operated in that state continuously for long enough then more catastrophic things might happen.

I wonder though... what exactly are all the possible things that might happen before the load burns itself out, and how many of those things have the potential to be truly catastrophic (beyond ruining the stove)? The first thing that comes to my mind is the failure of the ceramic glass... how long and at what temps would a runaway burn need to be to cause the glass to fail?

The worst-case scenario I can think of, as far as max temps, would be a full stove with the ashpan door left open. On the rare occasion I have left that door open for more than a minute or so, the resulting blast furnace is truly scary -- just listening to it roar is scary, regardless of what the thermometer might read. With that amount of air forced into the fire box acting as bellows, I expect the temps could get extremely high... any ideas? Obviously not as high as charcoal or coal.
 
That will turn a stove into a forge and will likely crack metal in the base and grate.
 
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With the Fireview and the Classic there is no ashpan, and when we light the stoves we usually leave the doors "open", which is really more ajar than agape (prolly too dramatic). I know the stove sounds, the telltale jingle of the door latch and the roar inside the firebox, but the time I reference above I was fully engrossed in my work and not paying a lick of attention to the contained fire in my shop (duh). And the thermometer was just hitting 700, but it scared the daylights out of me, anyway. I like the idea of using a kitchen timer; inexpensive and a practical way to bring yourself back to the reality of a contained fire!
 
That will turn a stove into a forge and will likely crack metal in the base and grate.

Right, but the question is, what -- if anything -- will it do besides ruining the stove?

EDIT: ... and ruining your underwear.
 
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I think prolonged misuse is also a problem here. What hapens when you have that crack in the metal base or the grate the next time you burn in the stove and possibly overfire again and again. Eventually something is going to give and result in things that should be contained no longer being contained.
 
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Right, but the question is, what -- if anything -- will it do besides ruining the stove?

EDIT: ... and ruining your underwear.

That is speculative. A cracked base will admit even more air. Hard to say if there will be a cascading failure or not.
 
I heard, on here, that a full stove of black locust could melt.........IDK:p
 
Leaving the door cracked or the ash pan door open and forgetting about it could easily burn your house down.
Especially if the secondary combustion action would not have been engaged. (aka: closing bypass)
Would it cause your stove to melt No, but it would cause damage to the chimney resulting in catastrophic failure.
I posted on here in several posts that when I was trying to get my stove up to temp I would leave it on high in an attempt to get the stove to 500. This caused the stove pipe temp to get very hot so that once or twice it caused the magnetic thermometer that is stuck on my double wall to spike. This caused damage to the Class A HT pipe that I have installed, this caused a change in my draft, since my stove is so sensitive to draft conditions I had the stove guys check on it and that when this issue was found. If I would have continued burning this way my house would have burned down.
 
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