Fireplace insert burn techniques/best practices?

[BillLion]

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?

Sorry for my lack of clarity; I'm functioning on a major sleep deficit today!

Yes, I think that helps. So if I just need to take the chill off the house, a fast, hot burn is the way to go. Makes sense.

But if I want to maintain consistent heat on a cold, winter day am I not better with a slow, hot burn? Will that "will also waste fuel, gunk up your chimney and pollute the environment" as you mentioned?

Sorry, if I'm being dense, I just want to make sure I understand. I really appreciate the help.

Maybe part of the problem is I have an insert not a stove, so I don't have any temperature gauge helping me know when I'm above or below 450.

 

[Jon1270]

But if I want to maintain consistent heat on a cold, winter day am I not better with a slow, hot burn?

Maybe part of the problem is I have an insert not a stove, so I don't have any temperature gauge helping me know when I'm above or below 450.

Me too, so I feel your pain. I check temps with an infrared thermometer, which is like a temperature-sensing gun you can point at surfaces that you can't touch. The other alternative is installing a thermocouple back in there and connecting the wire to a PID or other appropriate digital thermometer display. The IR thermometer is a bit awkward but you can think of it as an educational tool rather than something you have to use all the time.

 

[Jon1270]

Dang, half my response disappeared. Yes, a single slow, hot burn is better than a series of smaller,, fast and hot burns.

 

[BillLion]

Dang, half my response disappeared. Yes, a single slow, hot burn is better than a series of smaller,, fast and hot burns.

Thanks for both replies. The burn clarification is super helpful. And the infrared thermometer sounds like a great "toy" I'll need to invest in!

 

[BillLion]

One other question. When all that's left are red coals (in the waking hours) should airflow be increased to let them burn better or just keep it low until reload?

 

[Jon1270]

I think that one's kind of up to you. Extra air will make the coals burn faster but I haven't noticed it make much difference in the stove temperature, probably because the extra air also carries more heat up the chimney. If it's warm enough in the house and you can wait to reload, I'd keep it low and stretch the burn out until reloading is necessary. If you're in a hurry to reload and need to reduce that coal bed before you do, turn up the air.

 

[mass_burner]

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.

this is the case with my 2010 Morso per user instructions.

 

[mass_burner]

One other question. When all that's left are red coals (in the waking hours) should airflow be increased to let them burn better or just keep it low until reload?

For non waking hours, once I have a good bed of red hot coals, before loading with new splits, I turn the air to half, and max the fan speed. My logic is: that while stove is at its hottest, I should pump all that intense heat into the room. When the coals die down, then I rake forward and add new splits, lower the fan and open the air more. Am I off base here?

 

[BillLion]

I think that one's kind of up to you. Extra air will make the coals burn faster but I haven't noticed it make much difference in the stove temperature, probably because the extra air also carries more heat up the chimney. If it's warm enough in the house and you can wait to reload, I'd keep it low and stretch the burn out until reloading is necessary. If you're in a hurry to reload and need to reduce that coal bed before you do, turn up the air.

OK, that's helpful. I didn't know if there was a general rule of thumb, and I just want to maximize efficiency.

For non waking hours, once I have a good bed of red hot coals, before loading with new splits, I turn the air to half, and max the fan speed. My logic is: that while stove is at its hottest, I should pump all that intense heat into the room. When the coals die down, then I rake forward and add new splits, lower the fan and open the air more. Am I off base here?

I'd be interested to hear response to this as well. I do have one question for you. When you say crank up the fan during this process, does that mean you lower the fan at other times? I usually keep mine max at all times -unless it's just too blazing of course!

 

[mass_burner]

OK, that's helpful. I didn't know if there was a general rule of thumb, and I just want to maximize efficiency.



I'd be interested to hear response to this as well. I do have one question for you. When you say crank up the fan during this process, does that mean you lower the fan at other times? I usually keep mine max at all times -unless it's just too blazing of course!

I normally keep it on low. For one thing its kind of noisy on high, I also read here that it cools the stove. I'm still mentally chewing on that one, since "cooling" the stove by exchanging its warm air with the room's cold air is kind of the point, right? But when the rooms are up to temp, putting it on high isn't worth the increased noise.

 

[Grisu]

For non waking hours, once I have a good bed of red hot coals, before loading with new splits, I turn the air to half,

If you want to burn down the coals to get more room in the firebox that is perfectly fine. As others mentioned before, you are unlikely to get more heat that way as more goes up the flue. I usually like to avoid that therefore. Instead, during reloads I am adamant about raking all the coals forward. They burn then nicely down while the new splits catch fire.

and max the fan speed.

You don't get more heat like that. You just transfer the heat from your stove to the room faster. Imagine your house as a super-insulated box with the stove somewhere in it. The only heat you are loosing is the one going out the chimney. Any other heat retained by the stove will find its way into the rest of the house one way or the other.

When the coals die down, then I rake forward and add new splits, lower the fan and open the air more. Am I off base here?

Before opening the door I would always open the air fully. You may otherwise get unburnt gases, CO or other nasty stuff into your house. Rake the coals forward as you said, add new splits, let the door open until they have caught fire. Then close it and leave the air open for some time until the wood is mostly/fully engulfed and there seems to be very little smoke. Then you can close down the air. If you start closing down the air too early you risk that the initial smoke creates creosote in your flue.

 

[Grisu]

I also read here that it cools the stove. I'm still mentally chewing on that one, since "cooling" the stove by exchanging its warm air with the room's cold air is kind of the point, right?

When you cool the stove too much you get incomplete combustion which means some of your fuel (= potential heat) will go up the chimney. The heat from the stove will get into the room in any case. The fan just accelerates that process.

 

[mass_burner]

When you cool the stove too much you get incomplete combustion which means some of your fuel (= potential heat) will go up the chimney. The heat from the stove will get into the room in any case. The fan just accelerates that process.

But can the difference from low to high really cool the stove that much? I guess I can test this the infared thermometer. What is "too much"?

 

[BillLion]

You don't get more heat like that. You just transfer the heat from your stove to the room faster. Imagine your house as a super-insulated box with the stove somewhere in it. The only heat you are loosing is the one going out the chimney. Any other heat retained by the stove will find its way into the rest of the house one way or the other.

When you cool the stove too much you get incomplete combustion which means some of your fuel (= potential heat) will go up the chimney. The heat from the stove will get into the room in any case. The fan just accelerates that process.

Seriously, I can't even tell you how useful this is. I thought by turning down the fan blower I was wasting heat. This alone can really help our home be more comfortable -not to mention quieter!

 

[mass_burner]

You don't get more heat like that. You just transfer the heat from your stove to the room faster.

Makes sense. The hot air coming out all at once can you make you very warm and toasty if you just came in from outside!

 

[BillLion]

When you cool the stove too much you get incomplete combustion which means some of your fuel (= potential heat) will go up the chimney. The heat from the stove will get into the room in any case. The fan just accelerates that process.

Just to be clear, you're speaking of inserts, not just wood stoves, right? Sorry if this is an ignorant question. It's unbelievable how hard it is to find info like this via search engines queries.

 

[mass_burner]

Just to be clear, you're speaking of inserts, not just wood stoves, right? Sorry if this is an ignorant question. It's unbelievable how hard it is to find info like this via search engines queries.

For this coversation, I don't think it matters.

 

[Grisu]

Just to be clear, you're speaking of inserts, not just wood stoves, right? Sorry if this is an ignorant question. It's unbelievable how hard it is to find info like this via search engines queries.

While the general principle still applies, inserts are little bit of a different animal. There the heat can really accumulate around the stove due to the restricted airflow and potentially cause an overfire. I therefore run my blower on low for the first 2 to 3 hours of the burn cycle. In addition, should you have a fireplace whose back-wall borders the outside you will heat up the masonry there and loose heat to the yard. Putting Roxul around the insert will help with that heat loss. Running a blower to get the heat into the room will also help.

 

[Sully]

I think that one's kind of up to you. Extra air will make the coals burn faster but I haven't noticed it make much difference in the stove temperature, probably because the extra air also carries more heat up the chimney. If it's warm enough in the house and you can wait to reload, I'd keep it low and stretch the burn out until reloading is necessary. If you're in a hurry to reload and need to reduce that coal bed before you do, turn up the air.

I open it at end of every cycle. Other wise I get coals that just won't shrink. Than I can't get wood to fit coals are great but way to many means less wood

 

[Ko3n3k3]

I open it at end of every cycle. Other wise I get coals that just won't shrink. Than I can't get wood to fit coals are great but way to many means less wood

I don't mean to hijack your post but I'm having the same issue in my osburn 2400i. Is there a better practice to get rid of coals? It seems that my stove temp drops drastically but I have a large bed of red hot coals and a slight blue flame on them. It seems when i reload on top of that the coals don't get burnt up, just end up after my second, very hot, burn the coals just seem to double in size from the new load. Any help is appreciated. Thanks!

 

[BrotherBart]

Usually building large piles of coals is the result of adding wood every time the flames die down and stove top temp starts back down. If a person is around enough to do that then they should drag the coal bed forward and put a small split on top of it with the air open half to full. What happens is the flaming split will keep the stove hot while at the same time the coals below it burn up.

 

[Ko3n3k3]

Alright thanks sir. Do that til coals get manageable and then go for another full load, rinse repeat?

Thanks again

 

[Jon1270]

they should drag the coal bed forward and put a small split on top of it with the air open half to full.

This works because dragging the coals forward brings them closer to the air inlets AND knocks off the heavy layer of ash that probably coats them, so that the glowing charcoal is better exposed to that air. Unlike the flammable mists and gasses that rise into the air and burn off early in the cycle as visible flame, charcoal just sits there waiting for oxygen to come to it.

 

[Jon1270]

Maybe we need to design a stove such that the fire is built inside a rotisserie basket that begins to slowly rotate when the temperature drops below 400F...

 

[Ko3n3k3]

I want to make a skeleton shovel and just scoop up the coals, shake the shovel so the ash falls through and then dump them back down like the picture below but in a shovel. Does anyone else think that would be useful? (broken image removed)