Over firing; A modern concern?

[jdrab9er]

This question is more for the older guys here. Was over firing really a concern in the early 70's? I understand all modern EPA stoves warn against heating over 600F. I recall my Dad and others speaking very fondly of the older stoves, Fisher, Lange, etc. Also most modern brands use recycled cast, I didn't know if that had made any difference at all. I can't imagine it would.

Jon

 

[BrotherBart]

I used to overfire the crap out of my pre-EPA stove. It now sits out back as the firebox for a meat smoker. With a popped weld that you can stick a finger through. And it was built like the proverbial tank.

It is easier to over fire the newer stoves because of the inability to completely shut off the primary intake air and the unrestricted secondary air intake in a non-cat stove but getting steel too hot is getting steel too hot no matter the stove design. Keep doing it and you end up with a warped stove.

 

[Pagey]

Don't want to get all political, but I will throw this out there for shiats n giggles: maybe today's manufacturers warn of specific "overfire" temps because we live in such a litigious society now? I grew up with an early/mid 70's mode Fisher in the house, and I can never recall a time when my father said anything even remotely resembling an "overfire" of the stove. He still uses it today, in fact. It's never had a thermometer on it.

 

[BrotherBart]

All I can tell ya is the stove out behind the wood pile is thicker steel than any Fisher ever made. It never warped but that weld opened up like the Red Sea in the Moses movie. While it was kicking at over nine hundred degrees.

Treat your stove well and it will treat you well. My stoves now do not burn over six hundred, with some spikes to seven, because they are too damned heavy for this old guy to be lugging them out to replace them again.

 

[begreen]

This question is more for the older guys here. Was over firing really a concern in the early 70's? I understand all modern EPA stoves warn against heating over 600F.
Jon

Is this a correct statement? The stoves that warn about an over 600F stovetop temp seems to be the Hearthstone Soapstone stoves. Are there steel stoves that warn about over 600? Cast iron stoves?

BB, there's a big difference between a 650-700 stovetop which seems to be normal for the Summit/T6 and 900 degrees. Even then, the old Sierra seemed to have done well considering. How many years did the stove run at 900?

 

[jdrab9er]

The thermometers i've seen clearly show anything above 600 being too hot. And most of the PDF manuals for various stoves i've read online also warn against it.

 

[Battenkiller]

It is easier to over fire the newer stoves because of the inability to completely shut off the primary intake air and the unrestricted secondary air intake in a non-cat stove

I don't know about other old stoves, but I can practically melt my old Vigilant if I'm not careful. As it is, I've had stove face temp spikes over 1000º F on the IR gun, all while waiting for the damn thing to calm down... even after the bypass damper is shut and the primary air closed. Stove top routinely gets to over 800º, even on a half load.

I have fond memories of making out with my GF while sitting in the dark of her family room, her pretty face faintly illuminated by the red glow of the wood stove. I have no idea what kind of stove it was, but they always over-fired the thing, and it kept on ticking.

Still, most of the older stoves are heavily damaged on the inside from burning too hot. Not just warping and cracking plates, but the slow and inexorable deterioration of internal parts due to long term over-firing. I just gave my old Jotul 118 clone away to a guy to use in his shop. It was on it's fifth set of side baffle plates, and needs a sixth (I make my own out of 1/4" steel). Run it hot and you burn right through them in a couple of years. Eventually, I burned a hole right through the top baffle, but they were designed to be replaced as well. Even on my cheapo stove, the plates themselves are still in fine condition after all those years of burning hot as I could. Now, all the stove cement was blown out, but those old stoves were also designed to be rebuilt every five years or so, part of the general maintenance of the thing.

We have gotten so used to living in a throw away society. I'm on my fourth line trimmer in five years. The old electric Weed Eater just wouldn't die (10 years of steady use) until I left it in the rain and used it right after. I went with gas powered after that and they cost more to service than a new one costs, so I went back to electrics. My B&D Grass Hog just died yesterday - exactly one day after the two-year warranty expired. I was going to pick up a new Sawzall because they are supposed to have more power, but I'm told you can't even put new brushes in yourself. My old 8 amp saw still cuts like it was brand new, and when the brushes go, you just pop them in. All quality things from the past were designed to be used hard and rebuilt when they wore. Now, it seems that even something enduring like a wood stove has become a semi-permanent appliance if you give it just a little bit of abuse.

 

[oldspark]

I could overfire my old nashua in a heartbeat and in fact I did when we were putting up the house, with no insulation installed yet I would fire up the stove and leave the air intakes wide open and go back to the old haouse and wait for it to warm up. Only after buying a thermometer for the stack did I realize how hot that stove must have been, it was all 1/4 inch steel with some 5/16 around the fire box. All I did was warp it just a little (hardly noticeable) and crack it in a couple of places. I am luckly I did not burn down the new house.

 

[begreen]

The thermometers i've seen clearly show anything above 600 being too hot. And most of the PDF manuals for various stoves i've read online also warn against it.

The zone on the Condar appears to have 650 as the upper limit which is more reasonable. I just went through a half-dozen stove manuals and found the problem is that most stoves don't specify overfire temp. Many don't even specify proper operating temp. Jotul is pretty good saying the optimum range is between 400 and 600. But does not list over that as overfiring the stove. My experience with Jotuls shows overfire temp to be somewhere north of 850F.

 

[rdust]

Lopi states 800* in their manual for over-firing. I've been within 50* a time or two but usually can get it to settle in around 650-700.

 

[thewoodlands]

Lopi states 800* in their manual for over-firing. I've been within 50* a time or two but usually can get it to settle in around 650-700.

Lopi Liberty high burn is 600-800 anything over 800 like you said rdust is over firing, I've been at 750 with the air pulled out all the way then it backed down to 650 and held.


Zap

 

[op_man1]

The Jotul 450 insert does not specify a temperature range for overfiring - although it does offer the comment that if the stove is glowing it is too hot. Someone on this board once determined that the 450 glows around 900-950. I therefore run mine around between 650 and 750 or so and try to keep it under 800, for safety precaution. It has never glowed...

I don't think you can say that over 650 is overfiring (or even 800 for that matter) - it depends on the stove.

 

[jdrab9er]

This past winter I had to keep my Dutchwest no cooler than 800 just to keep it at 70 in the house. I only had it glowing once though. The steel plates inside are trashed. Melted BAD. Too bad VC doesn't make a larger model, its a nice looking stove.

 

[fossil]

I've pegged the thermo on the lower stovetop of our Liberty a couple of times, so I know it was running over 850°F...but not for long. No apparent damage to the stove whatsoever. I look to run it at about 600°F...when I'm paying attention. %-P Rick

 

[BrotherBart]

All I can tell ya is that the paint on the stove top and the magnetic thermometer goes "poof" at 1185 degrees according to my IR thermometer. Now that it is sitting out back on steel rails I fired the old stove to thirteen hundred and it didn't explode. The two times it got that hot in the house is why it is now out back.

I am perfectly happy with a five to six hundred degree burn in a stove. If you have to burn the crap out of a stove, start it earlier or burn two stoves.

 

[Pagey]

I suppose I should clarify my previous post. I wasn't meaning to imply that an older stove couldn't be overfired; only that I don't recall overfiring being mentioned/a concern with older stoves. I think that today's consumer is either: a.) more likely to file a suit or (and perhaps more importantly) b.) perceived as being more likely to file a suit. I work for a small community bank, and I am often surprised at some of the advice our legal counsel gives for such a small town (population for our entire county is under 8,000). And a lot of that advice stems from the fact that people are perceived to be litigious, just waiting for their chance to sue someone, especially a company with proverbial "deep pockets". So I am in no way surprised that many stove manuals today mention things like specific overfire temps and voided warranties.

 

[btuser]

I've been in a few situations where the insert got going and I had a top temp of 650+ headed for 700, and one time when I wasn't paying attention and it got almost to 800F. The annoying thing is not being able to smother the fire by shutting the air down all the way.

 

[branchburner]

I think that today's consumer is either: a.) more likely to file a suit or (and perhaps more importantly) b.) perceived as being more likely to file a suit.

Don't forget c.) perhaps more inclined to think "new, improved, and EPA-approved" translates as the ability to put the stove on auto-pilot and let it run itself without consequences.

 

[burleymike]

The manual for my Osburn 2400 says anything over 840f is overfiring. My dad told me about the stove in the first house they owned and over firing. He comes home from work one night and my mom had the stove glowing red hot a minute later he hears a roaring sound from the chimney, he immediately shut the damper off. After the stove cooled down a little he proceeded to change his underwear.

 

[Ratman]

It is easier to over fire the newer stoves because of the inability to completely shut off the primary intake air and the unrestricted secondary air intake in a non-cat stove

I don't know about other old stoves, but I can practically melt my old Vigilant if I'm not careful. As it is, I've had stove face temp spikes over 1000º F on the IR gun, all while waiting for the damn thing to calm down... even after the bypass damper is shut and the primary air closed. Stove top routinely gets to over 800º, even on a half load.

I have fond memories of making out with my GF while sitting in the dark of her family room, her pretty face faintly illuminated by the red glow of the wood stove. I have no idea what kind of stove it was, but they always over-fired the thing, and it kept on ticking.

Still, most of the older stoves are heavily damaged on the inside from burning too hot. Not just warping and cracking plates, but the slow and inexorable deterioration of internal parts due to long term over-firing. I just gave my old Jotul 118 clone away to a guy to use in his shop. It was on it's fifth set of side baffle plates, and needs a sixth (I make my own out of 1/4" steel). Run it hot and you burn right through them in a couple of years. Eventually, I burned a hole right through the top baffle, but they were designed to be replaced as well. Even on my cheapo stove, the plates themselves are still in fine condition after all those years of burning hot as I could. Now, all the stove cement was blown out, but those old stoves were also designed to be rebuilt every five years or so, part of the general maintenance of the thing.

We have gotten so used to living in a throw away society. I'm on my fourth line trimmer in five years. The old electric Weed Eater just wouldn't die (10 years of steady use) until I left it in the rain and used it right after. I went with gas powered after that and they cost more to service than a new one costs, so I went back to electrics. My B&D Grass Hog just died yesterday - exactly one day after the two-year warranty expired. I was going to pick up a new Sawzall because they are supposed to have more power, but I'm told you can't even put new brushes in yourself. My old 8 amp saw still cuts like it was brand new, and when the brushes go, you just pop them in. All quality things from the past were designed to be used hard and rebuilt when they wore. Now, it seems that even something enduring like a wood stove has become a semi-permanent appliance if you give it just a little bit of abuse.

I totally agree.

 

[Ratman]

All I can tell ya is that the paint on the stove top and the magnetic thermometer goes "poof" at 1185 degrees according to my IR thermometer. Now that it is sitting out back on steel rails I fired the old stove to thirteen hundred and it didn't explode. The two times it got that hot in the house is why it is now out back.

I am perfectly happy with a five to six hundred degree burn in a stove. If you have to burn the crap out of a stove, start it earlier or burn two stoves.

BB good point about the two stoves.

 

[Backwoods Savage]

This question is more for the older guys here. Was over firing really a concern in the early 70's? I understand all modern EPA stoves warn against heating over 600F. I recall my Dad and others speaking very fondly of the older stoves, Fisher, Lange, etc. Also most modern brands use recycled cast, I didn't know if that had made any difference at all. I can't imagine it would.

Jon

Apparently all stove manufacturers do not warn against heating over 600 degrees. Add one more; Woodstock. They don't want the stoves over 700 degrees.

 

[Battenkiller]

All I can tell ya is that the paint on the stove top and the magnetic thermometer goes "poof" at 1185 degrees according to my IR thermometer. Now that it is sitting out back on steel rails I fired the old stove to thirteen hundred and it didn't explode. The two times it got that hot in the house is why it is now out back.

I am perfectly happy with a five to six hundred degree burn in a stove. If you have to burn the crap out of a stove, start it earlier or burn two stoves.

My God, man, that's not a stove, that's a foundry! :ahhh: FWIW, a stove that is at 1200ºF is putting out over 5X as much heat as a stove at 600º. That'll cook anything. Forget clearance figure as well, I think they are usually determined for a 900º maximum surface temp. A stove at 1200º would probably set fire to a piece of wood 3' away. I once charred a broom handle in the corner where our Ashley was installed. I think it was about 3' away. Find a happy medium, maybe?

As far as the "good old days" of the 70s, the VC manual for its stoves back then says this:

Surface Temperatures

Monitor griddle temperatures with a surface thermometer. The usual operating range is 350-600 degrees, although slightly higher temperatures are alright when extra heat is needed.

Surface temperatures higher than 700 degrees are considered excessive. If any part of the stove or chimney connector glows, you are overfiring. Should overfiring occur, close the air inlet shutter enough to reduce the intensity of the fire.

So, yes, the term "overfiring" existed back in the 70s, and I'm sure before that as well. Yet in spite of the warning, I have seen many VC stoves (mostly Defiants) that were damaged because of overfiring. Never saw one with a crack in the exterior cast plates, but many have suffered cracked firebacks and warped damper plates. I try to keep mine under 750º because I think that, even back then, Vermont Castings was being a bit conservative. I have had a few scary episodes when the temp just shot up and I was afraid I wouldn't be able to rein it in, but there seems to be absolutely no damage to the stove due to these occurrences.

 

[oconnor]

The thermometers i've seen clearly show anything above 600 being too hot. And most of the PDF manuals for various stoves i've read online also warn against it.

I note that the thermo in the pick is labeled as a stove top thermo, but the temp ranges are the same as noted for single wall pipe temps. I wouldn't put any faith in the descriptions on them, nor in their accuarcy (covered lots in other threads)

As for Jotul C450 glowing temps, mine glows around 900*F. Seen it around the flue collar. Yours will glow around 900*F too. In fact steel glows around 900*F

https://www.hearth.com/econtent/index.php/wiki/Temperature_when_metal_glows_red

And yes, the paint does go Poof around 1000F. This is my polished temp trend indicator post 1000*F hh:

 

[Battenkiller]

And yes, the paint does go Poof around 1000F. This is my polished temp trend indicator post 1000*F hh:

Isn't that the Braille version?