Fireplace insert burn techniques/best practices?

[BillLion]

This is my 3rd season burning with a fireplace insert and I love it! I've read, experimented and learned a lot, but I would value some input from seasoned burners about the actual burning process. Specifically:

1. Do you keep airflow at maximum to keep the fire burning hot and the smoke pollution and creosote buildup to a minimum (as the EPA recommends) or do you slow airflow to slow the burn? Is it my imagination or does slowing the burn actually get it hotter?

2. How much wood do you burn at a time? Do you stuff it just at night or also throughout the day when you're able to monitor it? [I tend to get it going nice and hot, build a bed of coals and then add a piece or 2 at a time when the previous pieces are getting down to just red coals.]

3. How much green wood do you burn? Just kidding! I meant to ask, anything else to consider for maximum effectiveness?

Thanks in advance!

 

[USMC80]

airflow is kept at max during a startup or reload, then shutting down air all the way (results may vary) in stages.

Run full loads of wood (except in shoulder season)

 

[Craig S.]

airflow is kept at max during a startup or reload, then shutting down air all the way (results may vary) in stages.

Run full loads of wood (except in shoulder season)

x2 ... I'm a new insert guy, but this is how I do it.

 

[Jon1270]

Do you keep airflow at maximum to keep the fire burning hot and the smoke pollution and creosote buildup to a minimum (as the EPA recommends) or do you slow airflow to slow the burn?

Both, sorta. Early in the burn cycle (when you've added new wood) you'll generally need to keep the air wide open because you're typically either starting up a cold stove or refueling after the previous load has burned down somewhat. But it only needs to stay wide-open, more or less, until the temperature up at the top of the stove, around the secondary air tubes, is high enough to burn off any smoke that makes it up there. It helps to know that as long as there's wood in the stove that hasn't yet converted to charcoal, it will be giving off flammable gasses and mists and particulates (smoke). If it's hot enough then those gasses, mists, etc. burn as visible flame. But if something (like a cool stove top) chills those vapors enough then some of the gasses/mists/particulates will escape unburned, which is both wasteful and polluting. So, the idea is to keep the stove top temperature hot enough for complete combustion for as long as there is still wood in the stove that hasn't fully converted to charcoal. For my insert, that means a stovetop temp of at least 450F or so. Even without a good thermometer, it's fairly obvious when the stove gets this hot because it practically fills with flames.

So, the prime directive is to minimize the time during which there is wood not converted to charcoal AND the stovetop temp is below roughly 450F.. When the stove is cold (or lukewarm) it's generally best to leave the air wide open, but as things heat up the chimney will exert a greater pull and the airflow will increase even with the air control left in the same position. Sometimes it's useful to dial the air down a bit even before the stove is up to temp, because too much airflow can carry away more heat than necessary; just make whatever adjustments seem to get the temps up quickly. So long as the stove stays hot enough for the secondary tubes to do their job of completing combustion, cutting back the air won't hurt efficiency. And, once the wood is all converted to charcoal and you just have a glowing bed of coals, it doesn't matter if the stove temperature drops somewhat because there's no smoke anyhow, and nothing for the secondary tubes to do.

 

[Grisu]

The best and most efficient way to operate a modern stove is to load it up once you have established a nice bed of coals and the stove is warm. Recycling another post of mine:
See that you have a good bed of hot coals and a warm stove before loading it for the night. Put as many splits as you can fit in up to the top of the firebricks maybe leaving only a 2 inch gap to the burn tubes in the top. Let the wood catch fire and start a good burn, then close door. Leave the air all the way open until the wood is fully engulfed then start to stepwise close the air, maybe a quarter every 5 min. When the air is completely closed you should have nice secondaries in the top of the firebox and the stove top should read 500 F to 600 F for most stoves. If you have lots of cold coals left in the morning it could mean that your wood is not fully seasoned, check it with a moisture meter.

In the morning put on a bunch of smaller splits filling half to 2/3 of the firebox. Leave the air open a little bit (but not all the way once you have a good fire) to get a quick hot fire going; that should get the stove and the house back up fast. Once that fire dies down fill the stove up again similar to what I described for an overnight burn and let it cruise during the day. I manage to do a quick, hot fire in the morning (~2 h), two fill-ups during the day (~6 h each) and one overnight burn (~10 h) with nice dry hardwood.

If you leave the air open all the time you let a lot of the heat escape up the chimney. Did you never have problems with overfiring the stove?

 

[Soundchasm]

Bill, methinks the make/model of stoves makes a big difference. For instance, I did read the entire "Rockland tips" thread a while back. I found enough similarities that I was reassured, and enough differences to keep me experimenting and looking for new ideas.

Definitely try a few searches with your stove as the criteria. I'm sure you'll read heaps-a-plenty good stuff.

Might help to put your stove in your signature block, as well as some pithy wisdom the masses could use!

Here's that Rockland thread-
https://www.hearth.com/talk/threads/jotul-c550-rockland-tips-thread.21774/page-18

 

[aussiedog3]

pack it full with the biggest, driest splits that you have.(no matter the species of wood)
wide open air until it is cruising at it's sweet spot.
Stuff it full every time. You will learn.

 

[jdp1152]

There will never be a true recipe for what to do. Setups differ, environmental conditions differ, your wood species and condition will differ. That's a lot of permutations to prevent any single method for being right. Stoves are probably easier than a flush insert because your have temp as a guide. In the end, take it easy and learn your stove/ insert. It takes time. Gradually increase to the point you feel comfortable temp and safety wise. If safety becomes a concern and you're not hitting the temp comfort level, you're probably undersized. Several years into burning, you should be comfortable. Add a new stove/ insert to the mix, you'll start all over but with a considerably lower time frame to find the sweet spot. I wasted a lot of time a few years ago trying to figure this all out from internet sites, but you just have to gradually work your way up to find the right spot based on your situation. Only thing I'll adamantly say is the right way is starting your fires top down.

 

[BillLion]

Both, sorta. Early in the burn cycle (when you've added new wood) you'll generally need to keep the air wide open because you're typically either starting up a cold stove or refueling after the previous load has burned down somewhat. But it only needs to stay wide-open, more or less, until the temperature up at the top of the stove, around the secondary air tubes, is high enough to burn off any smoke that makes it up there. It helps to know that as long as there's wood in the stove that hasn't yet converted to charcoal, it will be giving off flammable gasses and mists and particulates (smoke). If it's hot enough then those gasses, mists, etc. burn as visible flame. But if something (like a cool stove top) chills those vapors enough then some of the gasses/mists/particulates will escape unburned, which is both wasteful and polluting. So, the idea is to keep the stove top temperature hot enough for complete combustion for as long as there is still wood in the stove that hasn't fully converted to charcoal. For my insert, that means a stovetop temp of at least 450F or so. Even without a good thermometer, it's fairly obvious when the stove gets this hot because it practically fills with flames.

So, the prime directive is to minimize the time during which there is wood not converted to charcoal AND the stovetop temp is below roughly 450F.. When the stove is cold (or lukewarm) it's generally best to leave the air wide open, but as things heat up the chimney will exert a greater pull and the airflow will increase even with the air control left in the same position. Sometimes it's useful to dial the air down a bit even before the stove is up to temp, because too much airflow can carry away more heat than necessary; just make whatever adjustments seem to get the temps up quickly. So long as the stove stays hot enough for the secondary tubes to do their job of completing combustion, cutting back the air won't hurt efficiency. And, once the wood is all converted to charcoal and you just have a glowing bed of coals, it doesn't matter if the stove temperature drops somewhat because there's no smoke anyhow, and nothing for the secondary tubes to do.

This is gold! Thank you so much. It helped me understand the WHY behind the WHAT. Thanks a bunch!

The best and most efficient way to operate a modern stove is to load it up once you have established a nice bed of coals and the stove is warm. Recycling another post of mine:
See that you have a good bed of hot coals and a warm stove before loading it for the night. Put as many splits as you can fit in up to the top of the firebricks maybe leaving only a 2 inch gap to the burn tubes in the top. Let the wood catch fire and start a good burn, then close door. Leave the air all the way open until the wood is fully engulfed then start to stepwise close the air, maybe a quarter every 5 min. When the air is completely closed you should have nice secondaries in the top of the firebox and the stove top should read 500 F to 600 F for most stoves. If you have lots of cold coals left in the morning it could mean that your wood is not fully seasoned, check it with a moisture meter.

In the morning put on a bunch of smaller splits filling half to 2/3 of the firebox. Leave the air open a little bit (but not all the way once you have a good fire) to get a quick hot fire going; that should get the stove and the house back up fast. Once that fire dies down fill the stove up again similar to what I described for an overnight burn and let it cruise during the day. I manage to do a quick, hot fire in the morning (~2 h), two fill-ups during the day (~6 h each) and one overnight burn (~10 h) with nice dry hardwood.

If you leave the air open all the time you let a lot of the heat escape up the chimney. Did you never have problems with overfiring the stove?

Recycled but new to me. Very helpful -thanks

Bill, methinks the make/model of stoves makes a big difference. For instance, I did read the entire "Rockland tips" thread a while back. I found enough similarities that I was reassured, and enough differences to keep me experimenting and looking for new ideas.

Definitely try a few searches with your stove as the criteria. I'm sure you'll read heaps-a-plenty good stuff.

Might help to put your stove in your signature block, as well as some pithy wisdom the masses could use!

Here's that Rockland thread-
https://www.hearth.com/talk/threads/jotul-c550-rockland-tips-thread.21774/page-18

Good point! I have an Avalon that I assume is at least a decade old. It was already installed in the home I purchased 2 years ago. Thank God, I didn't know about inserts prior and this fortune became the catalyst for my wood addiction.

I have learned so much from you guys about wood over the past months, and I now have learned a lot about burning more efficiently and effectively.

I loaded it full and lowered the airflow as advised and MAN IT WAS HOT Now some experimentation and I think I'll be all set!

 

[BillLion]

Only thing I'll adamantly say is the right way is starting your fires top down.

Really? Tell me more!

 

[BillLion]

This is my insert BTW...

 

[Jon1270]

jdp1152 said: ↑ Only thing I'll adamantly say is the right way is starting your fires top down. Really? Tell me more!

The idea with top-down starting (with a cold stove) is that the top of the stove gets hot before the heavier fuel at the bottom of the load gets warm enough to offgass much, so less fuel is wasted as unburned smoke. Your wood needs to be dry for it to work, though.

 

[avalondouglas]

I'm very much enjoying this thread, so thanks for the post BillLion! I read in here and other places to close the air completely? I too have an Avalon (Rainier) model. I can't get a ton in the stove, but it's rare that I have much of any coals in the morning. I shut it down about 95%, but not all the way. Yes, I'm new and have been learning for the last couple years, so maybe I'm not understanding. I also realize it matters what type of wood you're burning. I mostly try for oak and have begun my stock pile. Let me know your thoughts on shutting it down all the way...or how to effectively keep it burning at some rate throughout the night into the morning. Thanks all!

 

[Jon1270]

avondouglas, AFAIK it's not really possible to completely shut off the air on the current generation of stoves. They are designed so that they get some primary air even in the fully closed position, and there generally isn't a control on the secondary air supply at all.

 

[jdp1152]

Really? Tell me more!

Keeps your flue hot and drafting instead of smoldering your bigger splits. I mostly burn in evenings so I'm mostly doing pseudo cold starts

 

[Backwoods Savage]

I'm sort of a greenhorn at this but have been fortunate to have had several different stoves. Although our present stove gets run just a little bit different than our past stoves, there really is not a lot of difference one stove vs the other.

As everyone knows, a good coal bed is one of the essentials but that is not the case if starting with a cold stove. A layer of ash in the stove also helps and really is a must. On the top down or bottom up fires, that is pretty much a personal preference. We've used a bit or a "hybrid" starting technique that has worked well for us. Two splits in the bottom, forming a slight Vee with the wood. Lay 1/4 of a Super Cedar in the Vee and light it. Then lay either some kindling on top or just a small split or maybe two of them. This starts the fires just fine.

Reloads: First, I am amazed this year to see so many saying they close their drafts completely. In most cases, that is wrong. It is still better to leave some draft to the stove even if the epa stoves can not be completely shut down. Run the stove at full draft until the wood is charred then start closing the draft. You might close it half way and wait another 10-15 minutes before then closing it down to your regular draft setting. On our stove, the draft is numbered from zero to four. Our final draft setting is a bit below1.

One day my wife forgot the lesson she was taught. I came home to find her at the stove flipping the bypass lever open then closed, over and over. What? She said the stove was over-firing so was trying to keep it from doing so. I saw the draft completely closed so told her to open the draft to 1. She about flipped! However, the stove top cooled to the tolerable range and all was well. I don't think she will be closing that draft all the way again.

Each stove and each installation can and will be somewhat different. (like others with the same stove as ours with a setting of 1 1/4 or even more). However, there are still some simple principles to every stove. Of course the first principle is good wood. Then learning the stove.

 

[Jon1270]

I saw the draft completely closed so told her to open the draft to 1. She about flipped! However, the stove top cooled to the tolerable range and all was well.

That's a handy idea. Would it work as well on a non-cat stove?

 

[HDRock]

There is a lot of good info on here in old posts, (example search, Reloading https://www.hearth.com/googresults.html?cx=009218285606693233689:amuwobspuo4&cof=FORID:10&q=Reloading&sa=Search )

Search , Here ,It's at Top of page next to Site Menu, Search ttl, site, best way to search
For things like Starting a fire
'Running an EPA stove
Stove temps , etc

 

[Backwoods Savage]

That's a handy idea. Would it work as well on a non-cat stove?

Although I've never had that experience, I'm not sure if it would or not. Chances are that without enough air the secondaries may not fire off so the stove would not get as hot, but if I had one of those stoves, you can bet I'd be trying it.

 

[red oak]

The idea with top-down starting (with a cold stove) is that the top of the stove gets hot before the heavier fuel at the bottom of the load gets warm enough to offgass much, so less fuel is wasted as unburned smoke. Your wood needs to be dry for it to work, though.

Yes when I start a top-down fire hardly any smoke goes out of my chimney. It is really amazing to see.

 

[BillLion]

I'm very much enjoying this thread, so thanks for the post BillLion! I read in here and other places to close the air completely? I too have an Avalon (Rainier) model. I can't get a ton in the stove, but it's rare that I have much of any coals in the morning. I shut it down about 95%, but not all the way. Yes, I'm new and have been learning for the last couple years, so maybe I'm not understanding. I also realize it matters what type of wood you're burning. I mostly try for oak and have begun my stock pile. Let me know your thoughts on shutting it down all the way...or how to effectively keep it burning at some rate throughout the night into the morning. Thanks all!

Douglas,

I figured I wasn't the only one! Glad you're learning too. So much wisdom/experience here.

-Bill


And thanks everyone for all the tips on loading/reloading and even top down fires! I'll add that to my fire bucket list!

 

[BillLion]

So, I found an online manual for my insert (Avalon Olympic) and they gave these instructions (that agreed with what many said here):

"Overnight Burn


This stove is large enough to accommodate burn times up to eight hours. Follow the steps below to achieve an overnight burn.

1. Move the air control to high burn and let the stove become hot (burn for approximately 15 minutes).
   
2. Load as much wood as possible. Use large pieces if possible.
   
3. Let the stove burn on high for 15 minutes to keep the stove hot, then turn the air control to low.
   
4. 
   In the morning the stove should still be hot, with embers in the coal bed. Stir the coals and load small pieces of wood to re-ignite the fire, if desired."

HOWEVER, under a burn tips section they gave this contrasting suggestion:

• "Burn small, intense fires instead of large, slow burning fires when possible"

Any idea why they'd recommend that? Isn't the slow burn method more efficient?

 

[Jon1270]

Any idea why they'd recommend that? Isn't the slow burn method more efficient?

No, because the slow burn involves a lot of wood at relatively low temperatures, and therefore a lot of unburned smoke. The high temperatures of a small, intense fire will give you more complete combustion.

 

[BillLion]

No, because the slow burn involves a lot of wood at relatively low temperatures, and therefore a lot of unburned smoke. The high temperatures of a small, intense fire will give you more complete combustion.

Thank you. You said previously:

So long as the stove stays hot enough for the secondary tubes to do their job of completing combustion, cutting back the air won't hurt efficiency.

Just so I'm understanding, are you suggesting less wood or more airflow than an overnight burn would call for during daytime use?

 

[Jon1270]

are you suggesting less wood or more airflow than an overnight burn would call for during daytime use?

You might need to rephrase that because I'm not sure I understand what you're asking, but I'll guess. My earlier guideline to minimize the time the stove spends below about 450F while there's still hot, non-charcoaled wood in it applies both day and night. When they recommend small, intense fires rather than low, slow-burn fires, they're addressing situations where maybe the weather is mild, or for whatever reason you don't want the amount of heat that would yield from a full load that's run up to 450F+ and then dialed down to run for hours. The right way to get a smaller amount of heat is to have a small, hot fire. The wrong way is to fill the stove and choke off the air at a lower temperature, because while the latter will indeed generate the more moderate heat you want it will also waste fuel, gunk up your chimney and pollute the environment. Does that help?