Chimney Fire!

[wooduser]

Here's an interesting and amusing You Tube video on the chimney fire someone had, along with information on how to prevent such an episode.

I'm still looking for information on how to determine when a wood stove is being overfired, but I'd say some of the photographs in the video seem convincing to me!

 

[begreen]

That unused second crock with just a cover on it is not helping his situation. That needs to be sealed off tightly.

 

[bholler]

Here's an interesting and amusing You Tube video on the chimney fire someone had, along with information on how to prevent such an episode.

I'm still looking for information on how to determine when a wood stove is being overfired, but I'd say some of the photographs in the video seem convincing to me!

I have given you basic temps already. But another pretty basic rule is if any metal is glowing you are overfiring.

 

[Ludlow]

When its cranking and you smell a new smell, it's time to slow 'er down. Go by pipe temps 18" above collar, keep it under 500 and quit worrying.

 

[wooduser]

I have given you basic temps already. But another pretty basic rule is if any metal is glowing you are overfiring.

Thank you bholler.

In doing a good deal of additional reading today, I didn't find any objective study using temperatures as a guide to avoid over firing.

What I found was a lot of comments suggesting that over firing was indicated when the stove started glowing a dull orange, or that parts of the stove were being damaged by warping and such. Having used the damage as proof of overfiring, guessing was used to decide what temperature would have avoided the damage.

Well, I was hoping to avoid guessing, but apparently that's the best approach!

The bottom line for me seems to be that my practices seem to be avoiding overfired conditions:

The baffle above the fire isn't warped. The stove has NEVER started to glow.

So measuring the stack temperature with a probe thermometer, using 600 degrees as a maximum operating temperature and 700 degrees as a point to start taking definite action to reduce the temperature seems to be reasonable.


One surprise is that I was expecting to find SOMEONE doing combustion gas analysis to figure efficiency, but I haven't found any such animal, yet, being done with wood stoves, although combustion gas analyzers are routinely used with gas and oil furnaces and boilers. I'll have to keep looking for that. Still seems like a heap of guesswork and less science, but perhaps that's part of the appeal of wood stoves.

 

[wooduser]

I might add that I did observe one furnace overfiring. This was a forced air furnace, originally oil fired that the gas utility I worked for had converted to natural gas with a conversion burner years before.

When I went downstairs to the basement, I observed the sides of the furnace GLOWING a dull orange! Now that was the external sheet metal of the furnace, not the internal combustion chamber or heat exchanger. That was REALLY hot!

Well, I shut down the furnace and what I found was that someone had rewired the fan/limit switch. If the limit switch opens, it's supposed to shut the burner off. This switch had been wired so that when the limit switch opened, it shut off the FAN! No fan and no way to remove the heat being produced by the burner ----result, extreme overheating. Very lucky there was no fire.

 

[Ludlow]

Well, the first thing I was taught was that you never modify any appliance...PERIOD.

You replace parts with new parts....THATS IT.

If that isnt possible, you replace the unit....or turn down the job.

 

[bholler]

Thank you bholler.

In doing a good deal of additional reading today, I didn't find any objective study using temperatures as a guide to avoid over firing.

What I found was a lot of comments suggesting that over firing was indicated when the stove started glowing a dull orange, or that parts of the stove were being damaged by warping and such. Having used the damage as proof of overfiring, guessing was used to decide what temperature would have avoided the damage.

Well, I was hoping to avoid guessing, but apparently that's the best approach!

The bottom line for me seems to be that my practices seem to be avoiding overfired conditions:

The baffle above the fire isn't warped. The stove has NEVER started to glow.

So measuring the stack temperature with a probe thermometer, using 600 degrees as a maximum operating temperature and 700 degrees as a point to start taking definite action to reduce the temperature seems to be reasonable.


One surprise is that I was expecting to find SOMEONE doing combustion gas analysis to figure efficiency, but I haven't found any such animal, yet, being done with wood stoves, although combustion gas analyzers are routinely used with gas and oil furnaces and boilers. I'll have to keep looking for that. Still seems like a heap of guesswork and less science, but perhaps that's part of the appeal of wood stoves.

You havnt looked very hard pretty much all new stoves are tested that way at one point or another.

 

[bholler]

And i have already told you the temperatures that you are looking for. I didnt just make them up.

 

[wooduser]

And i have already told you the temperatures that you are looking for. I didnt just make them up.

As I explained, I presumed someone was inferring what temperatures likely resulted in actual damage to stoves. That's not "making things up." Neither is it really science.

But please tell me where you got those temperatures. I would like to be able to see how such figures were arrived at and how I can apply them to my stove.


<<You havnt looked very hard pretty much all new stoves are tested that way at one point or another.


No doubt you are correct. But I've already seen that manufacturers don't report hard numbers in their operating guides, and I haven't seen where these lab testing results are available for inspection and review. If you can refer me to such information, I'd like to look at it.

I would expect that laboratory testing reveals optimum conditions for operating the stove ----also not reported to the public.

You are quite right. My attempts to find this information this afternoon has been futile. If you can refer me to it I would appreciate it. .

 

[bholler]

As I explained, I presumed someone was inferring what temperatures likely resulted in actual damage to stoves. That's not "making things up." Neither is it really science.

But please tell me where you got those temperatures. I would like to be able to see how such figures were arrived at and how I can apply them to my stove.


<<You havnt looked very hard pretty much all new stoves are tested that way at one point or another.


No doubt you are correct. But I've already seen that manufacturers don't report hard numbers in their operating guides, and I haven't seen where these lab testing results are available for inspection and review. If you can refer me to such information, I'd like to look at it.

I would expect that laboratory testing reveals optimum conditions for operating the stove ----also not reported to the public.

You are quite right. My attempts to find this information this afternoon has been futile. If you can refer me to it I would appreciate it. .

I got those numbers from many years of experience and training in the feild as i said before. I am sure there are sources that provide them if you keep looking. I am not about to waste my time researching info i already know.

And no stove manufacturers dont provide those numbers to the public because they dont really matter to us. They use them to fine tune designs. They are of no use to us.

 

[Ctwoodtick]

Thank you bholler.

In doing a good deal of additional reading today, I didn't find any objective study using temperatures as a guide to avoid over firing.

What I found was a lot of comments suggesting that over firing was indicated when the stove started glowing a dull orange, or that parts of the stove were being damaged by warping and such. Having used the damage as proof of overfiring, guessing was used to decide what temperature would have avoided the damage.

Well, I was hoping to avoid guessing, but apparently that's the best approach!

The bottom line for me seems to be that my practices seem to be avoiding overfired conditions:

The baffle above the fire isn't warped. The stove has NEVER started to glow.

So measuring the stack temperature with a probe thermometer, using 600 degrees as a maximum operating temperature and 700 degrees as a point to start taking definite action to reduce the temperature seems to be reasonable.


One surprise is that I was expecting to find SOMEONE doing combustion gas analysis to figure efficiency, but I haven't found any such animal, yet, being done with wood stoves, although combustion gas analyzers are routinely used with gas and oil furnaces and boilers. I'll have to keep looking for that. Still seems like a heap of guesswork and less science, but perhaps that's part of the appeal of wood stoves.

As I explained, I presumed someone was inferring what temperatures likely resulted in actual damage to stoves. That's not "making things up." Neither is it really science.

But please tell me where you got those temperatures. I would like to be able to see how such figures were arrived at and how I can apply them to my stove.


<<You havnt looked very hard pretty much all new stoves are tested that way at one point or another.


No doubt you are correct. But I've already seen that manufacturers don't report hard numbers in their operating guides, and I haven't seen where these lab testing results are available for inspection and review. If you can refer me to such information, I'd like to look at it.

I would expect that laboratory testing reveals optimum conditions for operating the stove ----also not reported to the public.

You are quite right. My attempts to find this information this afternoon has been futile. If you can refer me to it I would appreciate it. .

As “into it” as many members of this forum are with proper wood burning, I don’t think that you’re going to get the exact numbers you are asking for from such and such a study, and, as has already been pointed out, it really does not matter. You will not have problems associated with bad wood burning if you stay within reasonable temp guidelines that you were given. In a nutshell, don’t burn wood so low that you smolder it and make a big smoky fire. On the other side of it, do not having a raging inferno in your stove either that could damage stove and/or chimney. If you even loosely follow you stove’s manual about operating stove, you should be fine. Life is too short to be as detail oriented as you’re being.

 

[KJamesJR]

Maybe this was mentioned before, but how often should you sweep your chimney if you’re burning 24/7 from say October to April? Class A double wall.

And how many of y’all burn while no one is home?

 

[Ludlow]

Doesnt apply to me but, my sister in law burns 24/7. Even while at work or away for the day.

 

[bholler]

Maybe this was mentioned before, but how often should you sweep your chimney if you’re burning 24/7 from say October to April? Class A double wall.

And how many of y’all burn while no one is home?

I burn 24/7 how often you need to clean depends on your stove your wood your burning techniques and your chimney. Most people can go a year between cleanings. At my old house i could easily go 2. Others need to clean monthly. But you need to inspect regularly until you know what you need.

 

[Dakotas Dad]

Maybe this was mentioned before, but how often should you sweep your chimney if you’re burning 24/7 from say October to April? Class A double wall.

And how many of y’all burn while no one is home?

There is no set answer of when or how often, because it depends on your wood and burning practices.

I honestly have not brushed my chimney in 3 years. I open the chimney at the bottom, look inside, it's at a level of clean I know to be about 1.5 cups of soot from 24 feet of pipe. That isn't enough for me to bother with, based on my experience with my stove, my chimney, my roof, my wood. I have a buddy that literally chokes his stove out and has to sweep a couple times a season.. can't convince him he is burning wrong. He is doing just what his dad taught him in the 40's.. Cut it, split it, burn it, choke the air down so you have coals in the morning...

As far as burning when gone. Every day.

 

[Dakotas Dad]

Thank you bholler.


The bottom line for me seems to be that my practices seem to be avoiding overfired conditions:

The baffle above the fire isn't warped. The stove has NEVER started to glow.

So measuring the stack temperature with a probe thermometer, using 600 degrees as a maximum operating temperature and 700 degrees as a point to start taking definite action to reduce the temperature seems to be reasonable.

.

If you are using a probe thermometer, 600 degrees is the start of the sweet spot.. not the point to start worrying. Unless you are Canadian.. then 600C is an issue.

 

[bholler]

If you are using a probe thermometer, 600 degrees is the start of the sweet spot.. not the point to start worrying. Unless you are Canadian.. then 600C is an issue.

For an old stove like his 600 internal pipe temp is probably about right. For a modern stove it is a bit hot to cruise at

 

[wooduser]

If you are using a probe thermometer, 600 degrees is the start of the sweet spot.. not the point to start worrying. Unless you are Canadian.. then 600C is an issue.

Wow. That's the biggest surprise I've had from reading on this site! I'm not used to stoking up the old stove to that level!

And frankly, I live in Seattle, Wa. It rarely gets cold enough to need that kind of heat output.

With the scrap wood I use, I throw in a piece or two of wood when the temperature gets down around 300 degrees, and that boosts it up to 400-500 degrees, at which point the room is quite warm, and I let it cool down again. Perhaps the stove is oversized for my needs. A smaller size stove might permit me to run a hotter fire longer, or continuously. I've often considered that as a possibility.

Burning that scrap wood is fine, except at night I tend to be less religious in fire tending, being asleep y'know. That can get pretty chilly by morning, which has encouraged the development of high speed fire building skills over the decades.

Also, on cold nights I'll sometimes set the gas furnace to switch on a maintain a minimum temperature overnight when the fire burns down. I don't have such an incentive to use my fast fire building skills in the morning, though.

I see that many people are concerned with the ability to maintain a fire burning overnight. I'm not especially concerned about that myself. I can throw three or four pieces of scrap 4x4 lumber on the fire at night and let it burn slowly. If it goes out and the furnace turns on, no big deal.

I don't mind fire tending ----I'm a born firebug!

 

[begreen]

Do you mean stove top temps? Our Seattle area stove top goes up to 650+ daily when temps drop below 40. Right now it's more in the 5-600F range.

 

[wooduser]

For an old stove like his 600 internal pipe temp is probably about right. For a modern stove it is a bit hot to cruise at

Thanks for the reply!

Frankly, I'm amazed that 600 sounds OK to use routinely. The wood stove owner's manu

Do you mean stove top temps? Our Seattle area stove top goes up to 650+ daily when temps drop below 40. Right now it's more in the 5-600F range.

I continue to be amazed.

Your stove is ranging between 500-600 degrees.

I throw a few scrap sticks on my fire and it burns up to 500, then I let it dies back and cool off to maybe 300 for an hour or so before throwing on a few more sticks.

It has to get REALLY cold for me to stoke up the stove to 600 ----you know ----15-20 degrees! RARE for Seattle!

More evidence perhaps that my stove is oversized.

Temperature right now at Boeing Field is 48 degrees:
https://w1.weather.gov/obhistory/KBFI.html


Seattle Pioneer

 

[bholler]

Thanks for the reply!

Frankly, I'm amazed that 600 sounds OK to use routinely. The wood stove owner's manu



I continue to be amazed.

Your stove is ranging between 500-600 degrees.

I throw a few scrap sticks on my fire and it burns up to 500, then I let it dies back and cool off to maybe 300 for an hour or so before throwing on a few more sticks.

It has to get REALLY cold for me to stoke up the stove to 600 ----you know ----15-20 degrees! RARE for Seattle!

More evidence perhaps that my stove is oversized.

Temperature right now at Boeing Field is 48 degrees:
https://w1.weather.gov/obhistory/KBFI.html


Seattle Pioneer

You are also running an old inefficient stove on scrap wood.

 

[firefighterjake]

Maybe this was mentioned before, but how often should you sweep your chimney if you’re burning 24/7 from say October to April? Class A double wall.

And how many of y’all burn while no one is home?

For folks new to burning wood or burning a new woodstove . . . I personally recommend at least inspecting the chimney monthly.

For folks who have gotten the hang of running their woodstove and have seasoned wood . . . most folks do it once to three times a year. A sweep at the start to make sure everything is free and clear, a sweep about mid-way through the heating season and maybe one final sweep towards the tail end.

For me . . . I try to sweep once a month, although I sometimes skip a month. I do this only because a) it is ridiculously easy for me to do so as I can sweep from the bottom-up in what is perhaps a 10 minute job and b) I know if I ever had a chimney fire the guys at work would never let me hear the end of it.

--

I pretty burn 24/7 . . . but the oil boiler thermostats are set to 60 degrees in case I am sick, lazy, etc. A benefit is when it is very cold outside and I hear the hot water starting to move through the radiators in the morning I know it's time to get up and reload the woodstove. That sound of hot water moving through the pipes is better than any alarm clock in getting me motivated to get up and get going.

But yeah, I burn when I'm not home . . . I just make sure to not just toss a bunch of wood into the stove and leave. It's a process . . . a process that takes time. When I leave the home the fire is humping along nicely at the expected temps.

 

[Dakotas Dad]

For an old stove like his 600 internal pipe temp is probably about right. For a modern stove it is a bit hot to cruise at

Well.. I have to go by what my stove manual tells me.. and that is that an "overfire" situation is happening when the stove top, surface temperature, when measured at the center of the center top stone, exceeds 600F. By my manual, 3-400F is a "low burn", 4-500F is a "medium burn", and 5-600F is a "high burn", as measured on that stone. No way in heck am I ever going to see 5-600F surface temps with an internal flue temp of 600F.

Right at this very moment, these are MY readings, on MY stove. 3 hours after a 3 split load was added to the over night coals, (10 hour burn, house stayed 72F with 30F and windy outside) My internal PROBE is reading about 575F, Surface temp on the offset box is 314F and the stove top is at 394F, coming down from a climb to about 425F an hour after I reloaded (from 260F stove top when I got up). Secondaries are firing, air is down to about 30%.

I don't know if a 6 year old Hearthstone still counts as a "modern stove".. nor do I seem to know what the OP is actually running, But I seriously doubt, again, that you can get a stove top surface temp to 600F, with a 600F probe temp. Modern stove or otherwise.

 

[vwmike]

That's video was painful to watch, but is pretty typical for a lot of people who burn wood. Growing up dad cleaned our massive brick chimney once a month, usually getting about 5 gallons of chunky creosote out. Had one small chimney fire in 40 years. Stove is still going and is a massive double door fisher clone, has to be at least 4 cu ft. After I left home I didn't burn again till 6 years ago when the house we bought happened to have a stove in the basement. I clean 20 ft of class a once a year and get maybe a cup of light ash out of it, I don't think dad actually believe me when I try and tell him how clean my chimney stays, lol