Burning 24/7 in Wood Stove - Show me the way....

[BurnIt13]

I'm very familiar with fire and have used plenty of wood stoves in my day but have never owned one. I intend to operate my stove 24/7 in hopes that it will be very close to a primary heat source. My wife and I work full time and due to our schedules I'm not sure we can accomplish a 24/7 burn. The stove will be a Napoleon 1400 (2.25cuft firebox) and the house is 1500sqft. Its a two story colonial and is fairly well insulated. Based around our current work schedule here is what we will try to do (assuming it is very cold outside):

5:45am - rake coals from previous nights low-burn. Fill firebox and adjust to high burn.
6:30am - set to low-burn and go to work.
4:30pm - rake coals from morning low-burn. Add wood and adjust to high burn.
5:30pm - set to medium burn. Add wood as necessary.
10:30pm - fill firebox and set to low-burn. Go to bed.

As you can see there is 8-10 hour interval while we are away at work or sleeping. Will this type of schedule work with 24/7 burning? Will there be enough coals to keep things going? Will I experience any excessive creosote build-up? We don't mind the house cooling down while we are at work or sleeping. The thermostat will be set to 55 and furnace will kick on if necessary.

Thanks in advance!

 

[North of 60]

Using Dry seasoned wood, with a decent stove @ 2.8 cuft or larger and you should have no problem with that schedual.
If I can do it with pine, poplar and spruce anybody can.

 

[fossil]

A whole lot depends on the wood...both the species (density/BTU content per pound), and the moisture content (% mc) of the wood (the lower the better, but never above about 20%-22%). 2.25 ft³ is a modestly sized firebox to work with trying to get long burn times, but overall, I'd say you've planned it out pretty well. Now you just gotta try it and see how it goes. Learn as you burn. Good luck with it, I think you'll figure out what works best for you in short order. Rick

 

[Dix]

That's pretty much my schedule during the winter with a 2.0 cubic fire box.

The state your wood is in is going to be the determing factor. The drier, te better.

Sounds like a plan

 

[Pagey]

I think you'll find that once you are burning well with nicely seasoned wood, you won't need anywhere near an hour to go from "high burn" to "low burn". More like 15-20 minutes depending on the species/load size/moisture content. Just keep that in mind.

If I let my Endeavor run a "high burn" for an hour with a fresh load, I think it would melt into slag.

 

[BurnIt13]

I think you'll find that once you are burning well with nicely seasoned wood, you won't need anywhere near an hour to go from "high burn" to "low burn". More like 15-20 minutes depending on the species/load size/moisture content. Just keep that in mind.

If I let my Endeavor run a "high burn" for an hour with a fresh load, I think it would melt into slag.

The only reason I figured an hour was to burn off any creosote that might have formed during the 8-10 hour low burn. Is 15-20 minutes good enough?

 

[ColdNH]

I have a napoleon 1450, basically the same stove, and I do burn 24/7 on basically the same exact schedule, leave the heat on 50 incase but it rarely comes on, the house does start to cool off by the time i wake up or get home from work, but I am easily able to stir some coals up and fire the stove up without a match.

 

[fossil]

I think you'll find that once you are burning well with nicely seasoned wood, you won't need anywhere near an hour to go from "high burn" to "low burn". More like 15-20 minutes depending on the species/load size/moisture content. Just keep that in mind.

If I let my Endeavor run a "high burn" for an hour with a fresh load, I think it would melt into slag.

The only reason I figured an hour was to burn off any creosote that might have formed during the 8-10 hour low burn. Is 15-20 minutes good enough?

You're going to want to have a thermometer or two on your stove/stovepipe. If you burn nice, thoroughly seasoned wood in a modern stove, and you watch the stovetop and/or stovepipe temperatures, therein lies the secret to clean burning and minimizing creosote deposition in the system...not by guessing, "Hey I'm burnin' real hot for x number of minutes, so I'm good." Let the thermometers be with you. Rick

ETA: If you go with double wall stovepipe, and you want to keep an eye on what's happening up in there, you'll need a probe-type thermometer, which will tell you the actual temperature of the flue gas stream. At a minimum, you want a thermometer on your stovetop.

 

[BurnIt13]

Thanks for the advice guys! As an engineer I tend to over-complicate and over-think things. If I treat the wood stove anything like my meat smoker it will have thermometers at all 4 corners, one in the middle, and two in the flue at various heights!

 

[fossil]

I'm a Mechanical Engineer. But I'm retired, so I've successfully resisted my urges to fully instrument my wood stoves and hook up data loggers. This ain't rocket science. As I said...you'll figure it out as you burn and learn. Rick

 

[BurnIt13]

Good tip BTW on the flue gas thermometer, I'd forgotten about those. I will be using double wall pipe so they will be a must. To my surprise the Napoleon manual says ideal flue gas temperatures are between 250-450F, which is much lower than anything I'm used to. It also says the ideal stovetop temps are between 500-600F so this thing must be pretty efficient.

The manual also says never to burn at the high setting for more than 30 minutes...

 

[fossil]

Re-read it carefully. Call the company if necessary. The stovetop temps of 500°F-600°F sound just right, but what you're calling the flue gas temperature of 250°F-450°F sounds to me to be more consistent with a measurement using a surface-mounted thermometer on single-wall stovepipe. Internal actual flue gas temperature as measured by a probe thermometer should be a good deal higher, I think. Anyway, you're going to figure it all out and do just fine with it. Rick

 

[Swedishchef]

Burnit13,

For my woodstove, the owners manual says almost the same thing as yours regarding flue gas temperatures. and it makes sense:

"...The ideal temperature for these gases is somewhere between 275o F and 500o F. Below these temperatures, the build-up of creosote is promoted. Above 500 degrees, heat is wasted since a too large quantity is lost into the atmosphere."

Mine normally runs around 375-425.

ANdrew

 

[fossil]

Burnit13,

For my woodstove, the owners manual says almost the same thing as yours regarding flue gas temperatures. and it makes sense:

"...The ideal temperature for these gases is somewhere between 275o F and 500o F. Below these temperatures, the build-up of creosote is promoted. Above 500 degrees, heat is wasted since a too large quantity is lost into the atmosphere."

Mine normally runs around 375-425.

ANdrew

Andrew, are you measuring that with a surface (magnetic) thermometer on single-walled pipe, or with a probe that sticks into the pipe and indicates the temperature of the gas stream inside the flue? Rick

 

[Swedishchef]

I am measuring it with a probe thermometer. I punched a small hole in my double wall stove pipe to insert my probe thermometer. It's between the 2 X 45 degree elbows.

Think about it: you don't want all the heat going up the chimney, but you DO want the temperatures above creosote formation which is about 250 degrees. I always warm up my chimney nice and toasty, my initial flue temp is 600-700. Then I turn it down and it coasts at about 425-450. By the time it reaches 300 degree flue temperature, there's barely any VOC left and the off gasing is complete: it's a smokeless burn.

I could be doing it all wrong. however, with 2.5 cords of wood burned last winter all I had was LESS than 1mm of coating on the inside of my flue. My chimney sweep (AKA installer) was quite impressed, as was I! He didn't want to bother cleaning it but I made him do so anyway.

Andrew

 

[fossil]

Sounds to me like you're doing it just right, Andrew. Thanks for the info, it's interesting and useful. I measure with mag thermometers on both stovetops and on both single-wall stovepipes just above the flue collars. What I find interesting is that I look for temps just like you're describing from my mag thermos on the stovepipes. I'd have thought there would be a larger difference between what I read with a mag thermo on the surface of the pipe and what you read with a probe in the gas stream...even with single-wall pipe in my case. Interesting...I'm indicating closer to the actual flue gas temp than I thought I was, apparently. Thanks. Rick

 

[BrotherBart]

Difference in distance from the flue collar makes all the difference in those surface temps Fossil. He is measuring EGT up a lot farther than you are measuring surface temps.

All part of playing with the variables. When I had a probe 24 inches up in the single wall pipe in the basement office I stuck a mag thermo next to it and found the 50% general use number to be pretty accurate. Not perfect. But flyable.

 

[fossil]

Yeah, man...for a while I was running my shop stove with, in addition to a mag on the stovetop, two mags on the single wall...one just above the flue collar, and one up about 5' higher, above my two 45°'s. When the stovetop mag was reading ~600°F, the mag just above the flue collar might be reading ~450°F, and the one up the pipe about ~250°F. This is what made me start thinking about changing out all my single wall for double. Still thinking about it. %-P Rick

 

[Swedishchef]

LOL

I just bought a stove top thermometer near the end of the year, I didn't use one at all until now. I see it more as a "nice to know" temperatures since the flue gas temperatures are relative to the stove top temps. As long as there's no creosote formation in my chimney, I am happy as a clam!

I do believe that there is a corelation between probes and magnetic thermometers. It depends on the location of both. As BB said, the further away from the stove, the bigger the difference in temps. It would be a good test to compare the two; then you'll know your relation.

Andrew

 

[astrodon]

One other thing that might not seem obvious to you (it didn't to me when I started burning) is that an inch or two of ash in the bottom of your stove really helps with the long burn cycles. I started off trying to keep my stove very clean and ash free. Thanks to some tips for the folks here, though, I learned that keeping some ash in the stove really helps those coals stay hot longer and made it easy to get 10 to 12 hour reloads with my stove, which is a bit larger than yours. But if your trying to get 8 hours out of a smaller stove, I think it still applies.


Happy Burning

 

[Highbeam]

I just don't think you'll make it through the day and still have coals to restart. Using a small non-cat stove to heat the small space you don't want a bigger stove but you won't get 10 hour burn times either. You just can't turn these stoves down that low. 10 hours is too much for 2.25 CF of non-cat.

 

[emt1581]

One other thing that might not seem obvious to you (it didn't to me when I started burning) is that an inch or two of ash in the bottom of your stove really helps with the long burn cycles. I started off trying to keep my stove very clean and ash free. Thanks to some tips for the folks here, though, I learned that keeping some ash in the stove really helps those coals stay hot longer and made it easy to get 10 to 12 hour reloads with my stove, which is a bit larger than yours. But if your trying to get 8 hours out of a smaller stove, I think it still applies.


Happy Burning

I would have never thought of that. I wonder why this happens? Does the ash act as an insulator or something?

Thanks!

-Emt1581

 

[firefighterjake]

One other thing that might not seem obvious to you (it didn't to me when I started burning) is that an inch or two of ash in the bottom of your stove really helps with the long burn cycles. I started off trying to keep my stove very clean and ash free. Thanks to some tips for the folks here, though, I learned that keeping some ash in the stove really helps those coals stay hot longer and made it easy to get 10 to 12 hour reloads with my stove, which is a bit larger than yours. But if your trying to get 8 hours out of a smaller stove, I think it still applies.


Happy Burning

I would have never thought of that. I wonder why this happens? Does the ash act as an insulator or something?

Thanks!

-Emt1581

Yes . . . acts as an insulator . . . helps preserve the coals.

 

[emt1581]

I just don't think you'll make it through the day and still have coals to restart. Using a small non-cat stove to heat the small space you don't want a bigger stove but you won't get 10 hour burn times either. You just can't turn these stoves down that low. 10 hours is too much for 2.25 CF of non-cat.

This is where a cast iron and more-so a soap stone seems to shine. They keep heating even after the fire goes out. So if you load it up and it's been burning for a while, the stove is going to keep radiating heat. Regardless, the coals will probably still be out...again, that heat output is the important thing in my opinion.

-Emt1581

 

[firefighterjake]

Will your schedule work? Hopefully . . . as others have mentioned two deciding factors will be the size of the firebox and the type/size/how well seasoned your wood is . . . having a well insulated home will most definitely help retain the heat.

As for the timing . . . it's not an exact science and you can't always set your clock to an exact schedule . . . but my schedule is similar to the one you outlined. I wake up between 5 and 5:45 a.m. and get the fire going by raking up the coals and throwing on some kindling (my more patient wife simply tosses on some small splits and waits.) The air is turned up and I wait . . . once the temps are high enough (as mentioned thermometers on the stove and for the stove pipe are important in my opinion) I begin to dial back the air . . . eventually getting the fire and the temps in the Goldilocks Zone ("just right") at which point the air control is shut all the way to a quarter open and the fire is clipping on nicely with secondary combustion going full bore. Usually, this is a 20-30 minute proposition and I'm out of the house (after a final check of the settings) by 6:30 a.m. Oh yeah, a word of warning . . . avoid the temptation to throw the splits on, turn the air up and shower for 10-15 minutes . . . I've done this twice and both times come out of the shower to find the thermometer on the flue close to going into the red zone.

Now here is where we differ. I'm fortunate. My work works part-time as a nurse . . . working nights. This means that five days of the week she is home during the day and awake . . . which means she can reload the stove when she wakes up . . . so when I get home from work the fire is almost always burning nicely. In addition, on one night of the week she typically stays up as she is in the process of switching over from sleeping at night to sleeping during the day so one night during the week she keeps the fire going through the night. That said, in a typical week even when she works she often has the fire going when she wakes up around 3-4 p.m. . . . but occasionally she'll sleep in and when I get home at 5 p.m. I'll get the fire going . . . either from the coals or sometimes from a cold start.

It should be mentioned that some folks think the stove's air control sets the temp . . . and in a way it does . . . but not always in the way folks think. When the air control is open all the way the fire may be raging, but a lot of heat goes up through the stove pipe . . . this is wasted heat. When the air control is halfway or closed most of the way in what some folks might think of the "low" setting you are setting yourself up to obtain the secondary combustion (for stoves that use secondary combustion) . . . what you get with this setting is not a long, low heat, but rather you'll get a reburning of the smoke which can produce a lot of heat . . . and you get a decently long burn time at the same time. I only mention this because with the old pre-EPA stoves if you wanted a long, low burn you would shut the air control and it would basically starve the fire of oxygen . . . the result being a long, low burn with very long burn times . . . but with little heat and at the expense of creating lots of creosote oftentimes. With EPA stoves shutting the air (providing you have high enough temps and good, dry wood) will result in decent burn times . . . but you will not get a "low" heat setting.

So how do you control the heat output? Well you can control the heat a bit with the air control . . . but a far better way is to control the heat output by your choice of wood . . . i.e. if you want less heat to take the chill out of an early Fall day you might not load the stove to the gills and you might choose wood that has fewer BTUs . . . many folks use their "junk wood" during this tiime of year. Me, I tend to use poplar, softwood slabs and my chunks and uglies. If you want a lot of heat you might load your stove to the gills and choose some good wood like oak, hickory, locust, etc. . . . and if you want to end up with some good coals you might choose wood that coals up nicely vs. a wood like poplar that results in few to any coals.

Creosote issues: Nah . . . not a problem providing you do three things. 1) It's been said before, but I'll say it again since every new burner forgets this most important rule. Junk in, junk out . . . in other words, unseasoned wood in the stove = cresosote build up. You need dry, seasoned wood . . . 22-25% moisture is the rule, but this dumb Yankee simply makes sure his wood is cut, split and stacked at least a year in advance.

2) Run your stove at the proper temps . . . here's where those thermometers come in handy. Most folks burning for the first year can't really gauge whether a fire is running too cool (i.e. producing creosote), running too hot (i.e. risking overfiring the stove or chimney) or running just right without the aid of thermometers. Just looking at a fire and feeling heat doesn't let you know you're burning hot enough . . . running the stove hot (but not too hot) is key to reducing the creosote.

3) Finally . . . I am a stickler for safety . . . even if you think you have good, dry wood and you know you're running your stove at the right temps you need to inspect your chimney . . . new burners should do so at least once a month . . . vets who have been running their stove for awhile may get by with just a couple checks during the year.