Whoops! Had a runaway today...

[agartner]

Yup, happens to the best of us. Came home from work, put the starter load in, had some coals so no Super Cedar necessary, just some newspaper. Let that run for a bit and closed my bypass and set the air to about halfway. At about 500 or so, just like I normally do, I open the bypass, open the front ddor, push my starter bricks to the back of the stove, and pack it full of 12 more biobricks and closed the door. Drop the air to 25% and sat in to watch a movie with the family. Movie ends and I'm lookin at the stove and think that the fire is ~really~ roaring.

I go check the stovetop thermometer and it's at 650 and climbing. Well that ain't right and I realize...yup, forgot to close that damn bypass. As soon as I close the bypass, up she goes to 700+. Damn. Close the air off and sit there and watch the lazy secondaries make a very pretty show on the door glass until they extinguish. Let her get back down to 650, go wide open on the air, let the flames catch, and drop back down to 25%. Cruising at 600 ever since.

 

[EatenByLimestone]

I hate when I get distracted and forget to check the stove after a lightup. I wouldn't worry about 700 though. My stove doesn't even start stretching it's legs until I get up around that.

Matt

 

[joefrompa]

According to Lopi, for my republic insert, 700-750 is "safe" to run at but will shorten the life of the stove over the long-run.

600-650 is the sweet spot for maximum output with maximum longevity. And it's supposed to burn very nicely from 400-600 in terms of cleanliness, etc.

 

[FGZ]

I haven't seen similar info for my Jotul, have I just missed it somewhere? I love "optimum" and "efficient" and "longevity", so I'm interested in those numbers.

 

[agartner]

I think the Kent is something line 1/4 inch double-wall steel, and I got her lined with Firebrick. ~I~ get uncomfortable with her at 700. I don't think the stove minds it at all.

 

[joefrompa]

I contacted Lopi (Travis) and got an e-mail response within 24 hours telling me the sweet spot is 350-600 for stove top temps, and that 700 was safe but could shorten longevity if constantly run in the 725 range (again, measured at stove top).

This applied to my specific firebox though...

Joe

 

[Gark]

A whoops - runaway here tonight too. Didn't leave anything open but the back side of the Encore cat got up to 830 f. an hour ago.
The top griddle measured 680f. at most. Dialed down the primary completely and it's settling down to rear=730 , top=530 now. The Encore's backside is where the cat burn chamber is. Will have to check it out tomorrow after the stove goes out. Maybe this is how some of the 2550 stoves fried the refractory box without getting above the manual's suggested limit of 700f. seen on the griddle. Or warped some cast iron parts. We'll see....

 

[EatenByLimestone]

As the temperatures start dropping I think you will start seeing a good many posts like this.

Matt

 

[Stonefly]

"As the temperatures start dropping I think you will start seeing a good many posts like this."

Is that because colder temps create a better draft?

 

[agartner]

Someone give Stonefly a cigar. Typically, the bigger the temperature differential between the house and the outside, the stronger the pull will be. But I didn't start to runaway due to more or less draft. Mine was operator error, pure and simple.

 

[Battenkiller]

Typically, the bigger the temperature differential between the house and the outside, the stronger the pull will be. But I didn't start to runaway due to more or less draft.

I disagree.

Draft strength isn't determined by the temperature differential between inside air and outside air, it is caused by the temperature differential between the flue gases and the outside air. In fact, you could get quite a roaring fire going with a cold house and a hot outside temperature, it's just not normal for folks to do this (except when they finish their install in August and just can't wait to try 'er out). :lol:

Runaway is a positive feedback loop caused by increased flue temps creating increased draft, creating even higher flue temps causing even stronger draft, and so on. So, yes, runaway is always due to too much draft, no matter whose fault it is.

IMHO you didn't have a runaway burn, you stove was just "stretching its legs" as mentioned above. I don't know if it's even possible to have a true runaway fire in a well-designed modern stove unless you are operating it way outside of its design parameters (forgotten open ash pan or door, etc.), they're much too controlled and restrictive to support runaway combustion. You might say your stove got away from you a bit, but it didn't actually runaway. And, like you say, it happens to the best of us... several times a season.

 

[Backwoods Savage]

What do you mean Battenkiller? I had to chase ours down the driveway once...

 

[Battenkiller]

What do you mean Battenkiller? I had to chase ours down the driveway once...

C'mon... you didn't chase it, you let it go and got that sweet Fireview to replace it. ;-)

 

[smokingolf]

What do you mean Battenkiller? I had to chase ours down the driveway once...

Why did your stove run away? Run out of wood to feed it. %-P