Newbie question - FLue Red hot

[oldspark]

I want to make a comment but I do not know where to start! :cheese:

 

[branchburner]

I want to make a comment but I do not know where to start! :cheese:

Ha! It is pretty funny this thread popped up right after yours. Even though we were telling you to relax and get to know your stove, you raised some good points about flue temps.

Any ideas from people on lifespans for stovepipes of various types (not just stainless liners) and how repeated high temps might shorten those lifespans? Not talking the 2100F chimney fire, but whatever it takes to make it glow (900-1000F).

 

[begreen]

I don't know the tested answer or if there is one. But I suspect that for code approved pipe, it's a lot. I knew some old timers that took heavy black single wall up to the glow point daily with their old stoves. And that stuff lasted years. I would expect stainless to do even better.

 

[fbelec]

Welcome to the forums, bill. I'll throw some food for thought out that might help a new comer, and others will correct me where I'm wrong. First, as far as the air control on your stove goes, think of it like this: it basically shifts the balance of air in your stove. When you initially build a fire and the wood first begins burning, this is "primary" combustion. The wood is still boiling off moisture so that it later reach a higher temperature and release more volatile gases. The air control when open fully will supply more fire towards the bottom of the firebox to aid this primary combustion.

As the wood heats up and the moisture is boiled away, it can then achieve higher temperatures. It will release volatile gases that, if hot enough and supplied with enough air, will burn and can contain up to 50% of the heat value in a load of wood. As you close down the air control, the balance changes, and more air begins to come into the top of the firebox via the burn tubes in the baffle (assuming your stove does have burn tubes). This shifts the balance of air away from the bottom of the firebox (primary combustion) and towards the top, where it can meet the volatile gases and ignite them for "secondary" combustion. You'll know it when you see it. Nice, rolling flames across the top of the firebox. They can vary in intensity and appearance, but you will know them when you see them. When you have strong secondaries, you will usually see a significant rise in surface temps of the stove.

Some users can close the primary air control all the way on their stoves and maintain active, secondary combustion. Others have to leave their air control open an 1/8 or 1/4" or so. You will learn the "sweet spot" on your stove just as I have on mine.

Another thing to keep in mind is that modern EPA stoves like to burn in "cycles" rather than by adding a split here and here. Once you've got a coal bed that is established enough to easily light off a load, put in the amount you'll need for that fire's heating needs. If it is milder weather, you may choose a few small splits placed loosely together for a quick, hot "flash" fire. If you in January and getting ready for bed, you may load up a full charge of oak, packed tight for an overnight burn. But in either case, it's best to establish the fire size/intensity you need at the time and then let it burn through that cycle without adding more splits here and there. Once you're down to charcoal again, open the primary air full, rake them to the front to get nice and hot, and reload as needed.

A final thought: if you did indeed have a chimney fire, I would take the time to inspect my liner for any additional deposits. Did you say how long the wood you are burning has been cut/split/stacked? It often sounds like overkill for new burners, but most agree that wood that has been cut/split/stacked (not sitting in the round, still) for one year is the minimum you want to operate an EPA stove with. We'll be glad to help any way we can.

Nice summary!

As with the OP, I've been also a bit confused about what is the best setting for the air control to avoid smoldering fires and creosote buildup. My stove will be installed Nov. 1 but trying to learn as much as I can before the first fire

From what I've been reading, restricting air flow too much can cause creosote buildup. Is this because you are causing the stove to burn at a lower temperate (and decreasing the temperature of the flue) or because you don't have 100% combustion and the fire is now releasing more unburned particles? Either way, it seems like you are asking for trouble from doing too many overnight burns... or is there a sweet spot for overnight burns so the fire burns at decent rate?

Also, are overnight burns mainly secondary combustion since you are closing the air intake so much?

-Andre

3 people with the same stove can't run them the same as the next guy. 1st guy can close down the primary air control all the way, and that sets up cruz control for that guys burn at a 400 degree stove top temp. the second guy can't go lower than 10% from closed or it will run to cool and the 3rd guy can't go lower than 25% from closed. every set up is different, even tho they have the same brand and model stove there are other variables. if you run your stove as per the manual says than the chimney for the most part should be ok. when your new at it you might want to check your chimney every three or four weeks until your confident on your burn practices. the manual will give you what your stove top temps should be run at, but if your house is bigger than the next guy's, or it a extra cold day you might want to run it at 500 rather than 400. once you get the feel of burning, over night is not a problem. the stove will do it's thing, and as long as you have a proper setup to code and smoke and carbon monoxide alarms you'll be safe

 

[fbelec]

one other thing that was not touched here was that soapstone stove top temps react slower than a steel or cast iron stove. so when you are running up a new load of wood you want to keep that in mind. my hearthstone reacts alot slower than my vermont castings.

good luck
frank

 

[oldspark]

I can't stay quiet any more, this is pretty much what I was talking about and have been off and on for the last 6 months, look up any article about chimney saftey and they recomend a flue temp sensor. This is not saying you run your stove with it (never claimed I was), it is just a saftey device so your pipe dont glow or worse. So think what you want that is all I was ever saying.

 

[fbelec]

I can't stay quiet any more, this is pretty much what I was talking about and have been off and on for the last 6 months, look up any article about chimney saftey and they recomend a flue temp sensor. This is not saying you run your stove with it (never claimed I was), it is just a saftey device so your pipe dont glow or worse. So think what you want that is all I was ever saying.

that's not a bad idea. i didn't get to read your post on this as i have been mostly off from the forum during the summer. that is not a bad idea tho. most of us use the (what's that smell) safety device before we get up to check. and then say oh s___.

 

[firefighterjake]

[quote author="billc4" date="1287776096"]Thanks everyone any more insite is appreciated, there seems to be a lot of varying opinions which is a good thing.

I did have the chimney and the stove "professionally" swept and inpsected on September 9th this year. I have used the stove typically at night maybe 20 times since the sweeping and inpsection. I did not use the stove prior to this because I wanted to be sure everything was good to go. At night I would typically start the stove at 6:30-7:00PM and put teh last wood on it at 9:00 so the fire would have burned down enough for me to feel comfortable going to sleep between 10-11PM. Primary air was left open the whole time and the last wood was always 1-2 new pieces.

OK . . . first off . . . loading the wood and running the air in this fashion is doing you and your stove an injustice . . . I say this because what is happening is that you are missing out on two great things -- the chance to see the wonderful secondaries in full blown action and get all that "extra heat" and equally as important . . . you're missing out on the long burn time. As mentioned earlier . . . load the stove with more than just one or two sticks of wood, get to the stove up to temp, turn down the air, marvel at the secondaries and wait several hours until you're left with coals and start the whole process over again.

I did read the manual online prior to using the stove and I guess what I took from it under Operating the stove efficeintly in the manual where it described the different burn rates was that the high burn rate (with the air control wide open) was best for not having creosote buildup. This is teh quote from the HIgh burn rate paragraph "Burning smaller amounts of wood at a high burn rate creates the most efficeint fire, emits the lowest amount of pollutants, and creates the least amount of creosote in your chimney." I thought was doing everything correctly. I had no smoldering or smokey fires, glass was clean, and no big chunks of unburned wood in stove when I was up the next morning.

You are partially correct . . . on a day like yesterday where I wanted a little bit of heat, but I didn't need to really have the heat pour out I only stuck 2-3 small splits (chunks actually from my chunnks, punks and uglies pile) in the stove . . . and I opened up the air all the way . . . what this did was give me a bit of heat, without over-heating the place . . . what I sacrificed however was a long burn time and the lost heat to the chimney . . . the glass stayed clean and there was no smoldering fire . . . but this was not the most efficient or cleanest burning fire . . . a word of caution . . . I did this with 2-3 small splits . . . maybe 10 inches or less in length (vs. my normal 18-21 inch wood) . . . I would most certainly not load the stove to the gills with my good wood and leave the air open . . . and it should be further added that this was done while I was inside the home.

Again, the best way to burn . . . the best in terms of being the most efficient, clean burning and getting a long burn is to burn in cycles and turn down the air . . . the key to knowing when to turn down the air is often found with the use of a thermometer -- either a stove top thermometer or a flue thermometer. In my first year of burning I most often used the stove top thermometer to know when the temp of the stove was at the point where I could start to turn down the air in quarter mark increments . . . now I most often use my probe thermometer (for my double wall pipe) for giving me guidance as to when to turn down the air.

How do I know I'm burning correctly . . . just having clean glass is not the end-all, be-all definitive answer (although it may be a sign) -- seeing those secondaries firing off and seeing no smoke coming from the chimney are better indications . . . and then of course having very little creosote to deal with in the chimney is perhaps the most definitive answer.

What the manual does not really talk about is the secondary burn and "dialing in" the primary air control position to create the secondary burn. I have been reading about that now on the forums. A lot of the wood burning seems to be done based on feel/experience because of the huge number of variables in stoves, wood, and installation. So I have a lot to learn and experience yet.

I think the manual touches on the secondary burn . . . in fact when I read the manual the other day I read a passage about slowly closing the air once the stove has been burning for a while . . . perhaps this is not the best way to state how to achieve a secondary burn . . . as others have said every stove works differently . . . perhaps this is why the manual doesn't say start shutting your air at X degrees and stop when the air control is pushed in a quarter of the way . . . however I will echo a few thoughts here that may help you . . . 1) get some thermometers . . . they really do help to let you know when to start closing the air and if you are burning efficiently and 2) experiment with your stove . . . in time you will learn how far you can shut the air without the fire smoldering, how long the fire will burn and what good secondaries look like.

For me I guess I will have to overcome the fear of dialing down the primary air control and going with a medium or lower burn rate after the fire is established.

. . .

 

[firefighterjake]

. . . For me I guess I will have to overcome the fear of dialing down the primary air control and going with a medium or lower burn rate after the fire is established.

I would have more fear about destroying my stove pipe and chimney . . . and more fear of going through my stockpile of wood . . . far before I would worry about dialing down the air.

About the worse thing that could happen if you dial down the air too soon is the glass blackening up . . . well scratch that . . . I suppose you could dial down the air too soon, the glass blackens up, you've wandered off somewhere
for a long time and then you come back and open up the door to the firebox and the sudden rush of air allows the fire and the combustible gases milling about there to burst into flames in a particuarly explosive fashion . . . however, I suspect this second scenario to be extremely unlikely given the fact that you see pretty cautious and don't strike me as the type of person to wander off from the stove unless you know it's burning OK.

More likely what would happen is that the glass starts to blacken up . . . and you open the air control . . . fire bursts back into flame . . . you let the fire go for a bit . . . and then turn down the air a few minutes later . . . and when the fire continues to burn . . . you try turning down the air a bit more . . . and then you achieve the secondary burn . . . and start panicking when the Portal to Hell appears in your stove . . . at which point you get on line and write out a thread wondering if it is normal to have the Portal to Hell appear in your woodstove.

For peace of mind I will have the same company come out to sweep/inspect the chimney. That did the cleaning a month and a half ago.

I think I would do this as well . . . just to err on the side of caution.
Bill

 

[firefighterjake]

I can't stay quiet any more, this is pretty much what I was talking about and have been off and on for the last 6 months, look up any article about chimney saftey and they recomend a flue temp sensor. This is not saying you run your stove with it (never claimed I was), it is just a saftey device so your pipe dont glow or worse. So think what you want that is all I was ever saying.

+1 . . . as mentioned I tend to use my flue thermometer most often to know when to start closing the air control to achieve a good secondary combustion.

 

[oldspark]

I can't stay quiet any more, this is pretty much what I was talking about and have been off and on for the last 6 months, look up any article about chimney saftey and they recomend a flue temp sensor. This is not saying you run your stove with it (never claimed I was), it is just a saftey device so your pipe dont glow or worse. So think what you want that is all I was ever saying.

+1 . . . as mentioned I tend to use my flue thermometer most often to know when to start closing the air control to achieve a good secondary combustion.

I remember you telling me that a while back, my questions seemed to confuse some people and we had different opinions, I am going to stay away from posts like that and just see what other people are doing and learn on my own.

 

[firefighterjake]

I can't stay quiet any more, this is pretty much what I was talking about and have been off and on for the last 6 months, look up any article about chimney saftey and they recomend a flue temp sensor. This is not saying you run your stove with it (never claimed I was), it is just a saftey device so your pipe dont glow or worse. So think what you want that is all I was ever saying.

+1 . . . as mentioned I tend to use my flue thermometer most often to know when to start closing the air control to achieve a good secondary combustion.

I remember you telling me that a while back, my questions seemed to confuse some people and we had different opinions, I am going to stay away from posts like that and just see what other people are doing and learn on my own.

Nah . . . don't be a stranger Old Spark . . . everyone is entitled to their opinions . . . truth is what works for one person may not work for another . . . but it doesn't make that other person's method or opinion wrong . . . for example clearly Dennis is wrong in splitting wood vertically and insisting that it is the best method . . . but I still respect Dennis and look forward to reading his threads and opinions.

 

[vvvv]

I can't stay quiet any more, this is pretty much what I was talking about and have been off and on for the last 6 months, look up any article about chimney saftey and they recomend a flue temp sensor. This is not saying you run your stove with it (never claimed I was), it is just a saftey device so your pipe dont glow or worse. So think what you want that is all I was ever saying.

+1 . . . as mentioned I tend to use my flue thermometer most often to know when to start closing the air control to achieve a good secondary combustion.

I remember you telling me that a while back, my questions seemed to confuse some people and we had different opinions, I am going to stay away from posts like that and just see what other people are doing and learn on my own.

Nah . . . don't be a stranger Old Spark . . . everyone is entitled to their opinions . . . truth is what works for one person may not work for another . . . but it doesn't make that other person's method or opinion wrong . . . for example clearly Dennis is wrong in splitting wood vertically and insisting that it is the best method . . . but I still respect Dennis and look forward to reading his threads and opinions.

ya, keep posting. I like it short & sweet vs long & not as sweet by verbose dillution

 

[oldspark]

Well I want to stay away from long winded rambling posts that seam to go no where which many of mine do. :lol:

 

[bcarp6]

Just a quick update - the chimney sweep and the company's GM are coming out tomorrow at 2PM to see the stove/flue, so I will post what they think happened.

 

[bcarp6]

Update - so just the GM of the sweeping company was out with his tools. The only thing he could see was that the baffle on the top of the stove (the one with the secondary combustions tubes, which apparently moves) was forward about a 3/8" +/- from the back of the stove. This could have been letting the hot gases go straight up the flue. He slid it back by hand and said to see if that makes a difference. He also said that the flue as it comes out of the back of the stove should be horizontal or slightly sloped up mine is sloping down before it goes vertical. He said this could have also contributed to the overheating. He said flue was fine and was going to have the sweep come out to make sure the flue leaving the stove was horizontal or slightly elevated.

Sounds like all is well - any comments on the feedback I received from teh sweeping company?

Thanks again.

Bill

 

[tutu_sue]

I'm confident they found the cause of the problem. Now you can relax and enjoy a toasty warm house!

 

[Backwoods Savage]

Update - so just the GM of the sweeping company was out with his tools. The only thing he could see was that the baffle on the top of the stove (the one with the secondary combustions tubes, which apparently moves) was forward about a 3/8" +/- from the back of the stove. This could have been letting the hot gases go straight up the flue. He slid it back by hand and said to see if that makes a difference. He also said that the flue as it comes out of the back of the stove should be horizontal or slightly sloped up mine is sloping down before it goes vertical. He said this could have also contributed to the overheating. He said flue was fine and was going to have the sweep come out to make sure the flue leaving the stove was horizontal or slightly elevated.

Sounds like all is well - any comments on the feedback I received from teh sweeping company?

Thanks again.

Bill

Bill, you need a minimum of 1/4" rise per foot of horizontal. So that definitely could have added to the problem but no doubt was the whole problem.