Newbie question - FLue Red hot

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bcarp6

New Member
Oct 22, 2010
9
Southern NH
1st time wood burner, stove was previously installed in house that is new to me.

Stove is Hearthstone Homestead 8570H

STove is intalled in an existing brick fireplace with brick hearth and mantle. Chimney is brick on teh outside and 28' high. Woodstove is secondary source of heat and located in living room. Chimney is on outside of house.

Had it sweeped and had the stove went over a little more than a month ago. The flue is a 6" double wall. THe sweep thought is was a 2005 install.

I have had several successful fires and have a condor stovetop thermometer that I have placed on teh back left hand corner. I had been just running the stove with teh primary air control wide open until today. I would typically have the stove top thermometer at 400-425F and really never really added more than 1 large piece of wood once I got a good bed of coals going.

Tonight I put 2 pieces of wood and a small split on a good bed of coals and the flue started to glow red as the wood statred to take off with teh air control open all the way. The stove top therm was about 425F. I will quickly got up and closed the primary air all the way and the fluestatred to cool, going from red back to steel colored. I than opened the air contol up a little so that the wood was not putting off sooty smoke as it burned and closed enough that the flue was not turning red. I also got a box fan pointed at the stove to help cool the area. All this took place in 5 minutes or so. The stove top them reached 500-525F when I did this. My flue is mostly in teh chimey so I did not have a flue thermometer.

Now the big question what do I need to do before I run the stove again and did I ruin anything.

Bill
 
I am unsure about that stove specifically but in general a hearthstone soapstone stove top should not, per Hearthstone, exceed 600 degrees f . So I doubt you damaged the stove, the pipe on the other hand, that I could not tell you what to do if anything.
 
It turned red cuz you had the stove wide open and all the heat was going up the flue. You need to back it off after about 10-20 minutes and let that EPA stove do it's thing. You will save wood and get more heat that way. Put that thermometer on the center stone and don't let her get up over 600.
 
Could I have damaged the metal flue? I am sure the stove is fine because the temps were below the 600 mark by 50+ degrees, but I had just never seen the flue coming outof he stove red hot like that.

Bill
 
you got to find a spot on the pipe to put a thermometer. if you had a screaming hot fire going in the stove it would take a while before it would show up on the thermometer on the stove. if your pipe started to glow you have some creosote buildup on the pipe and it got lit off. one of three things. 1 the sweep didn't do as good of a job as he was suppose to. 2 you are burning to smokey.( it doesn't sound this way because your running the stove at 400 - 425) or your secondary is not firing off. 3 you got wood that is not dry enough. from what you said about running it wide open and only running at 425 degrees i would say your wood is not dry enough and sooner than later if continued burning this way you'll have a chimney fire.

question: when your starting up the stove about 15 to 20 minutes into a fresh fire, if you open the loading door do you hear hissing?
 
I don't think you damaged the pipe as long as it was for a short spurt.
 
fbelec said:
you got to find a spot on the pipe to put a thermometer. if you had a screaming hot fire going in the stove it would take a while before it would show up on the thermometer on the stove. if your pipe started to glow you have some creosote buildup on the pipe and it got lit off. one of three things. 1 the sweep didn't do as good of a job as he was suppose to. 2 you are burning to smokey.( it doesn't sound this way because your running the stove at 400 - 425) or your secondary is not firing off. 3 you got wood that is not dry enough. from what you said about running it wide open and only running at 425 degrees i would say your wood is not dry enough and sooner than later if continued burning this way you'll have a chimney fire.

question: when your starting up the stove about 15 to 20 minutes into a fresh fire, if you open the loading door do you hear hissing?

I had the stove going for about 2 hours and was consistently above 400F. The wood burned down to coals and at 400 so I figured I would throw the 3 pieces on and it took off. My air control was wide open ever since starting this fire and I never throttled it back. Sat on the couch and watched it go. Noticed the flue turning red hot so I got up and closed the air control because I was frekaing out. I am using the previous homeowners wood which was in the basement and is pretty dry so I am not sure thats the case. No hissing heard on any of the wood. Glass is wicked clean so I didn't think I was burning too smokey. Any chance I could have just let all the heat from the burn go up the chimey with no regulation which caused the pipe to overheat?

Since the metal flue goes up into the fireplace any thermometer would have to be real close to the stove in order to read it. Would a magnetic one suffice?

Should I have someone come out to inspect the stove/flue before using again?
 
north of 60 said:
Why are you running your stove with the air control wide open? You will never achieve an efficient secondary burn.

Because I am new at this....Not having had a wood stove before I am trying to learn as much as I can, from reading on this site, but most knowledge seems to come from doing with wood stoves.

For instance today I learned that in order to increase my stove top temp I need to dial back the air control which keeps the heat from overheating the flue and keeps it in the firebox.

I am trying - this is just foreign to me and I assumed that if i had the air wide open I would not have a smoldering fire...
 
If the pipe was glowing you set off deposits in it. Period. That stove wasn't burning hot enough to give you a glowing pipe with out it.
 
billc4 said:
north of 60 said:
Why are you running your stove with the air control wide open? You will never achieve an efficient secondary burn.

Because I am new at this....Not having had a wood stove before I am trying to learn as much as I can, from reading on this site, but most knowledge seems to come from doing with wood stoves.

For instance today I learned that in order to increase my stove top temp I need to dial back the air control which keeps the heat from overheating the flue and keeps it in the firebox.

I am trying - this is just foreign to me and I assumed that if i had the air wide open I would not have a smoldering fire...

Sounds good billc4. Welcome to the Hearth. I would download a copy of the manual if you dont have one #1 on your list.
I think this was creosote that lit off in your flue to cause it to go red as a result of WET wood. As you are concerned that you are causing smoke when you turn it down after you have a good bed of coals after loading again with wood. Keep reading.
Cheers.
 
Homestead has a pretty good manual..

http://www.hearthstonestoves.com/assets/files/document_library/Homestead8570Manual.pdf

Welcome.

Read. Ask. Learn.

My guess is you didn't hurt the stove, but for that model, thermometer on stove goes center of top center stone. Stay under 600. Make sure your wood is well seasoned. I load up, get a good burn going, say 15 minutes or so, then back the air down in a couple steps, generally settling at about 20% air or so.. secondaries kick in up top.. and cruisin' she goes.. repeat in 6-7 hours or so.
 
You probably don't want to load one split at a time, classic newb mistake that will lead to less efficient burning, more tending and crud in the flue. Do larger loads less frequently, keeping the air backed off to avoid overheating the stove.

As BB said, sounds like a mini chimney fire in the bottom of your flue from the iffy burning practices. If you have a SS flue in the chimney I am sure you are fine.
 
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.
 
To emphasize previous comments: read the manual from cover to cover. Those instructions are specific to your stove. Advice on here may be specific or general, but at least you'll know the manufacturer's advice for your particular make and model. EPA-certified stoves today operate differently than the "metal boxes" that many grew up using.
 
Random thoughts . . .

First off, welcome to the forum . . . if you've got questions about wood burning this is the place to be.

Next, it sounds as though you bought the place and didn't have the manual to look at . . . understandable . . . however Dakota's Dad posted a link to the manual on-line. I would highly suggest reading the entire manual . . . pages 33-37 pertain to operating the stove . . . but I read the entire manual to make sure the stove was actually installed correctly per the manufacturer's specifcations.

As others have said the reason the stove pipe glowed red was because you made the rookie mistake of thinking that having the air control all the way open would mean more heat since you most likely also saw lots of flames in the firebox . . . what this does is allow more of the heated air to enter the chimney . . . as mentioned by others and the manual . . . the goal is to bring things up to temp and then slowly close down the air control . . . Pagey had an excellent tutorial of sorts on how to do this . . . and you should end up with a burn that is both clean, efficient and if the stove is a secondary burner -- you'll have a nice light show . . . oh yeah, doing so will also result in more heat . . . a lot more heat . . . going to where you want it the most -- in your home to keep you warm and not up the chimney to keep the squirrels, chipmunks and birds warm.

And to echo . . . these stoves work best by cycling . . . rather than adding 1-2 splits every hour or so they really do best by loading the stove and then dialing down the air to achieve secondary burns . . . you can add a stick or two at a time . . . and in fact my wife sometimes does this during the day during the shoulder season when she just wants to keep the fire going and doesn't need or want a lot of heat . . . but for a truly long and efficient burn you will want a nice load and let the stove do its thing.

Would you or should you inspect the chimney . . . probably no damage was done . . . but why risk it . . . if you haven't had the chimney inspected by a professional sweep I would say now is a good time to do so . . . just to give you peace of mind.
 
Todd said:
It turned red cuz you had the stove wide open and all the heat was going up the flue. You need to back it off after about 10-20 minutes and let that EPA stove do it's thing. You will save wood and get more heat that way. Put that thermometer on the center stone and don't let her get up over 600.


Welcome to the forum billc4.


I agree fully with Todd.

I do not agree with some other posts, for example, the flue could not have got that hot from the stove fire because the stove top was not that hot. It is common for many stoves that the flue temperature will greatly exceed that of the stove top when the draft is set fully open. Shoot, I can get our flue temperature over 700 (magnetic thermometer on flue; single wall) with the stove top only maybe 150 degrees.
 
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.

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.

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.

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.

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.

Bill
 
billc4 said:
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.

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.

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.

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.


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.

Bill

Bill, you have to overcome the fear of dialing down the air! You need to overcome leaving the air open! There should be no fear in dialing down but big time fear in leaving that draft full open! Hang in there and you'll get the hang of it.
 
billc4 said:
north of 60 said:
Why are you running your stove with the air control wide open? You will never achieve an efficient secondary burn.

Because I am new at this....Not having had a wood stove before I am trying to learn as much as I can, from reading on this site, but most knowledge seems to come from doing with wood stoves.

For instance today I learned that in order to increase my stove top temp I need to dial back the air control which keeps the heat from overheating the flue and keeps it in the firebox.

I am trying - this is just foreign to me and I assumed that if i had the air wide open I would not have a smoldering fire...

Welcome Bill, good that you came here to get advice. Before burning the stove anymore, please download the manual for proper operation of the stove. The damper needs to be closed down in increments as the wood fire develops. It will not smolder as long as you are burning well seasoned, dry wood. Reread the section about "Operating Your Stove Efficiently" where they talk about regulating the primary air control in greater detail.

http://www.hearthstonestoves.com/wood-stoves/stove-details?product_id=19
 
I did print a copy of the manual, and will keep reading and re-reading pages 31-38. Looks like I need to determine what a mid range setting is too.

Thanks again and I will update when I get the sweep out to the house.
 
My EPA stove also says make sure you open the air control before opening the door to add more wood so flames don't shoot out. Make sure you shut it again and don't leave it wide open once your fire is going. I got mine up to 600 this week and freaked me out. Was busy and my wood is good and dry. My manual does not give me a temp for overfiring; wish it did.
 
Pagey said:
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
 
Don't hesitate to ask more questions. We were all beginners at some point. It may help to have a thermometer on the stovetop so that you can see the correlation between the air control setting and the stove temperature. It will also help prevent overheating the stone.
 
Everyone gave great advice and you will surely get the hang of it soon. I want to include a little ditty about high flue temps not from operator error, but from the ceramic baffle board on top of the firebox. It has be free of holes and properly seated. I was having high flue temps even on the lowest air setting and it turns out that my baffle had a corner lifted and wasn't cemented down well. The corners of the baffle are rounded while the frame it sits in is square and the factory cement didn't cover cover those corner holes or cement the baffle to the frame. The baffle board was recemented this week with Hearthstone cement and I had a medium size fire going today and at cruising stove top temp 400F the flue was around 400F where as before the fix it was 650F to 700F flue temp.
 
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