"Hot Fire" Question

[nehimama]

A while ago, someone here mentioned that they run a "hot fire" every morning for a few minutes in their wood burning stove. This helps keep the creosote from building up, apparently.

I just had my flue pipe brushed out to remove the creosote. I'm burning well-seasoned wood, and it seems this season the creosote built up rather quickly.

When running a "hot fire", just how hot (Degrees Farenheit) is "hot"? I'm terribly afraid of an overfire, so need some idea of the best temp to run it to, and for how long, before damping down.

Thanks in advance.

NeHi

[7thswan]

I do it every day. How hot? Mine, hot as it can get, there is hardly any in there if done every day. I hear the bits of creosote tinkling on the walls as it drops off. My Dh has gotten up there with the brush, but it never needs it. I would not do this if you have any elbow joints where the creosote will land and build up. They are also weak there. Is you pipe high enough to get a good draft? If not you will also get a faster build up. I never leave the stove while full open and it is airtight, so when shut down it is Off.

[amelia]

In my opinion, you should aim to maintain a hot, rapidly-burning fire at all times. Damping down, while giving a fire longevity, will result in the dangerous build-up of cresote in the chimney. It doesn't take long for a dangerous amount of flammable creosote to accumulate if you are burning a stove with a restricted air flow.

I aim to run my stove at a temperature no less than 500 degrees (as measured by a stove-top thermometer). On colder days, I keep it more in the range of 600-700. I control the temperature primarily by increasing or reducing the amount of fuel (wood) that is being burned, NOT by restricting the air flow to the fire.

In addition to assuring that you're burning dry wood, it's a good policy to keep the size of the splits relatively small--again so you avoid a smoulder. I aim to keep mine of a size that I can pick up with one hand.

BTW, when I recommend always maintaining a "hot" fire, I am not referring to the stove temperature, but rather to how aggressively the wood is burning. You can maintain a modest stove temperature and still have a "hot" fire by reducing the amount and size of the fuel and giving the fire plenty of air.

[nehimama]

Thanks for all the input and advice! I knew I'd get some good folks here to chime in.

There are no elbows on my flue pipe; it's straight, and tall enough for a good air draw. I have a stovetop thermometer on the base of the flue pipe where it connects to the stove collar. It is marked off to indicate low and mid-range temps, but the one that scares me is the "overfire" mark, way over on the right-hand side of the thermometer!

If a fire that hot is a good thing, why would they call it "overfire"? That's a frightening-sounding term.

NeHi

[ceresone]

My fireplace, with a insert, burns hot all day, but is "dampered down" at night. Its hooked to a large flue--and I NEVER get creosote-but on the other hand, I have a regular flue, made from flue blocks, and a tile liner--that I cant use. For some reason, creasote gets so bad in it, that it runs down the pipe, and onto the floor!! And, I burned as hot a fire, with dry wood, as I could get.
Fire cheif came out, removed the c converter, thinking to help--didnt.

[7thswan]

Originally Posted by ceresone

My fireplace, with a insert, burns hot all day, but is "dampered down" at night. Its hooked to a large flue--and I NEVER get creosote-but on the other hand, I have a regular flue, made from flue blocks, and a tile liner--that I cant use. For some reason, creasote gets so bad in it, that it runs down the pipe, and onto the floor!! And, I burned as hot a fire, with dry wood, as I could get.
Fire cheif came out, removed the c converter, thinking to help--didnt.

sounds like moisture. can you have a pipe put in the chimney.

[woodsy]

300-400 degrees is the optimum temp. for efficiency and least pollution.
I brushed my chimney late summer and after a month of slow fires in Oct.had to brush it again due to buildup plugging things up. Surprise-surprise ;The wood did not season so well over the mostly wet summer here.
I think you would have to go over 1000 degrees to damage a tile lining, chimney fires range from 1500-3000 degrees and this is where damage can occur.
Disclaimer: Nothing i say here can or will be used against me in a court of law.

[Stephen in SOKY]

I use this product weekly & while it is NOT a replacement for regular manual sweeping, it does help keep any buildup flaky & dry, which equates to less flamable. I always use 2 scoops the day before I sweep (Seldom get much) to loosen any buildup up & make it sweep easier/more thoroughly. $10 per season is cheap for a little extra peace of mind.

http://www.tractorsupply.com/home-im...-2-lbs-3198195

[amelia]

Nehi, you might consider investing in a stove-top thermometer that has actual degree markings. The last time I looked, they ran for about $10-15. I actually keep two on the stove--one on the stove top and the second on the stove pipe, about halfway between the stove and the ceiling. I rarely look at the thermometer on the stove pipe, but when I hear a lot of metal expansion noises in the pipe (pops and creeks), I will keep an eye on it just to make sure that the temperature is in the "safe" range and not rapidly rising. It would probably be my first warning of a chimney fire.

EDIT: My stove is cranked up to about 700 degrees right now, and I'm hearing lots of metal expansion noises. I just checked the stove pipe thermometer, and it is reading 300 degrees--just fine.

[wyld thang]

what species of wood are you burning?

[wyld thang]

Originally Posted by amelia

I rarely look at the thermometer on the stove pipe, but when I hear a lot of metal expansion noises in the pipe (pops and creeks), .

I don't have a thermometer on mine, but I listen to my stove too. WE dont' get much creosote buildup, and we don't run a hot fire(unless to warm up the house if we've been gone long). We burn mostly ash and oak, seasoned, with a bit of fir for kindling/hot fire. I think type of wood, it's seasoning and the shape, draft and run of your stovepipe has at least as much to do with creosote than how hot you run your fire.

My stovepipe is straight up and is about 2 stories tall and drafts real well. It's very easy to get a fire started in my stove.

[Bearfootfarm]

For some reason, creasote gets so bad in it, that it runs down the pipe, and onto the floor!!

Your pipe should be attached in such a way that any drips are channeled to the inside.

If you have more than one section of pipe, you can probably turn them around so the higher ones fit inside the lower ones.

[nehimama]

The wood I use is well-seasoned oak. The thermometer has the actual degree markings ( in F and C) as well as being marked as follows:

100 - 200 degrees F = Creosote
200 - 525 degrees F = Burn Zone
525 - 800 degrees F = Overfire

It's a Rutland thermometer, and is located ON the stovepipe, just where the pipe meets the stove.

I normally keep the fire in the low to medium Burn Zone, as I get overwarm too easily. Blame that on my Eastern European heritage!

NeHi

[amelia]

I know I would have trouble keeping a fire burning cleanly at less than about 450 to 500 degrees. However, my draft is not great, and my stove is small, so perhaps I need a hotter stove than you do to keep things from going into a smoulder. Again, it's not the temperature of the firebox that determines whether you've got an appropriately "hot" fire to prevent creosote build-up. If you're wanting to run a cooler stove, just cut smaller pieces of wood and cut back on the amount of wood in the firebox.

One suretale sign of how you're burning is what the smoke looks like coming out of the chimney. When things are burning well for me, I do not see any smoke at all--just barely visible "heat waves," especially on cold days. Not surprisingly, I am unable to achieve the no-smoke, heat wave effect until I get things burning steadily at at 450-500 degrees. You might try paying attention to the quality of the smoke and judge from that.

[clovis]

My dad heated in an insert for years, always tried to keep hot fires, and never had creosote problems. Of course, he also tried to burn dry wood, but he never found that different species of wood made that much difference.

A funny note: Dad was given four monster sized elm trees. The 'experts' all told him that it wouldn't burn, and that it would creosote the flue so bad that you would have to chip it out with a hammer. Of course, those particular 'experts' had never burned wood for heat in their entire lives!!!!!

[Wis Bang]

We have a franklin stove at our cabin.

I do have an airtight replacement that I just removed from mom'[s garage b/4 she sold the house for later.

We always start out w/ the damper wide open and the bottom vents open. This makes a strong draft and gets the fire going nicely. We always let it burn this way for an hour or more until there is a bed of hot coals before partially closing the damper and shutting the bottom vents.

We remove the pipe each spring and clean it out. The chimney is block w/ a tera cotta flue and there isn't much buildup. We usually only have a fire 10 - 15 days each fall/winter for hunting. Like was mentioned above dry and seasoned wood and I check the smoke color. Usually just a trace of grey but mostly just heatwaves...