Economical Burn

[PhatWood]

I'm a new owner of a woodburning insert and I'm totally obsessed. I have a Pacific Energy Summit and I am burning wood that I had spent the past year splitting and seasoning. I've been reading on this website trying to get some good ideas on how to make and sustain a good fire.

I have a lot of questions, but I will start with this one. What is the best way to make the logs last the longest? What I've been doing is getting the fire started with the kindling. Then when it's down to hot embers I add bigger logs, let them catch fire and char, then slowly turn down the damper until I get a secondary burn where the flames come in from the top. Then I just let it burn like this and it stays in the "burn zone" temperature (according to my magnetic thermometer) for a while, but it eventually dips down into the "creosote" temps pretty soon. I feel like I am burning a lot of wood, but maybe that's what I should expect. I wanted to know what's the most efficient way to burn the logs and greatly appreciate any advice you can offer.

Thanks in advance.

 

[Wood Pirate]

I just purchased and installed a freestanding Pacific Energy Summit. I really like the stove. I have definitely been using a lot less wood then I did with my old stove.
I have been pretty much burning it the same way you are. I char the wood and then turn the air down low. I have been turning the air down all the way once it gets going (and not sure if that's the best thing to do) but it burns slower and I can see the secondary combustion. Burns very clean.
I think (and could be wrong) that when you have coals putting out heat, you don't have to worry as much about the temps on the gauge showing creosoting.

 

[bsruther]

There are always pointers and tips to be had, but in the end, trial and error and finding what works best for you is what will give you the most from your wood.
I don't know if starting a fire a certain way will help to burn the wood more efficiently or not, but I've always started fires with the load of splits piled on top of the kindling. Works every time.
A lot of people talk about the top down method, but I've never tried it and don't care to.

 

[begreen]

I start a fire with two medium-large 6" splits loaded N/S with a gap of 2-3" between them. In the gap goes balled up newspaper, pistachio nut shells, or if I am rushed, a chunk of SuperCedar. Then criss-crossed across the gap are kindling sticks. I ignite them, let the kindling and logs get burning pretty well with the air wide open (~10min.), then place another log in gap, but slightly askew so that it doesn't squelch the fire. I let that get going strongly (+10 min.) and then add wood to fill the firebox. Shut the air down 50% and let the wood get fully involved in flame (+5-10 min.) Shut the air down to 25% or all the way if the fire can take it without smoldering. Usually this will heat for 6-8 hrs. or 8-10 hrs with hardwood.

 

[Hogwildz]

The wood ain't ready, hence you have to let more air in to burn it, and less than stellar burn times.
Large splits or rounds on bottom topped with mediums & smalls to fill in the top. Your issue is the larger pcs will be even wetter, and will burn like crap.
All stoves diminish in temps, and will eventually fall into the " creosote" temps. With good wood, and hitting a good temp, by the time it gets back down into the creo zone, there is not issue of creo, as it will be in the coaling stages with most the nasties already burned off.

 

[PhatWood]

Thanks for all the advice. My wood is a mixture of sizes, but mostly smaller thin pieces that I made when I got a little carried away after I discovered my love for splitting wood. I have a bunch of larger splits that I will have for next year. The wood may not be ready, even though it's been stacked and covered properly for a year. However, it's mostly red oak, which I understand can take a long time to get really dry. Either way, it's still burning nicely and I think that the burns are extending with practice.

Begreen, I will try your technique. I haven't been fully filling the firebox except for the overnight burns. I seem to get a really nice coal bed that lasts for a while and seems like a clean burn.

One thing I keep reading about is the "runaway burn" that everyone seems to be afraid of. What is that? It sounds scary and I don't want to have that happen. Is that the same thing as an "over fire"? I keep reading about ways to avoid a chimney fire, but how do you know if you have one?

Thanks, guys!

 

[begreen]

Almost all runaway fires are not. A runaway implies out of control. What most people are seeing when they report a runaway is a large secondary bloom burning off. That is when they find out there is no brake pedal on their stove. But the stove is still under control. As the gases are burned off the wood it will settle down. To avoid this condition, don't fill it with a full load of thin splits. They are going to offgas much quicker than large splits. Instead start with larger splits loaded N/S and some kindling in the valley between them. And turn down the stove's air control soon enough to regulate the rate of offgassing. Most newcomers wait too late, trying to go by stove top thermometer temperature. Don't do that, go by what you see. With small splits in a fresh startup they may be fully involved in flame yet the stove top is just 250F. Regardless, turn down the air until the flame starts slowing down. Then let the flame regain strength. Repeat when the flame is strong again.

 

[Grisu]

One thing I keep reading about is the "runaway burn" that everyone seems to be afraid of. What is that? It sounds scary and I don't want to have that happen. Is that the same thing as an "over fire"?

A runaway burn can lead to an overfire. It happens when the wood in the firebox gets really hot and starts outgassing at a high rate. The secondaries will be blazing and when you are looking into the firebox it is like you opened the gates to hell. Your stove temp may easily climb above 800 F on such occasions which indicates an overfire. If you cannot avoid it in the first place through proper burning practice, try the following: Open your primary air all the way. Carefully open the door first slightly then almost fully. That breaks the secondary combustion and the inrushing "cold" house air will cool the firebox.
Such a runaway burn can happen when the wood was loaded into a hot stove onto hot coals and the primary air was not closed fast enough. However, with your semi-dry wood I would not be too concerned.

 

[begreen]

I have had some monsterous secondary blooms but the thermometer never has hit 800F in the T6. It would take a major spaceout for that to happen. FWIW overfire is an ambiguous term. 800F is very hot, but not hot enough to get metal glowing red which is how some stove mfg. define overfiring. I've had the old Jotul up that hot due to my spacing out and it is still in very good condition after 30 yrs.

 

[PhatWood]

I've been trying to get the secondary burn effect with the gasses burning up from the top, which seems to happen when I turn the air control down. Maybe I'm not scared enough, but I like the way that looks and seems to heat up the oven nicely. I have a magnetic thermometer that I keep on the faceplate directly above the oven glass door which guides me to keep it in the 300-600 range. To get it in that range, after establishing a coal bed, I lay some splits N/S or E/W (I haven't really paid much attention - whatever fits (some are really long and only fit EW)), keep the air control opened fully for a few minutes until they catch fire and char, then I turn it down to 50% and usually see the secondary burn at that point. Then the temp rises and after a few more minutes I turn the air control all the way down.

Interestingly enough, I just got an infrared laser thermometer today and I think that I've been getting temps 100-200 degrees hotter than the magnetic thermometer says. Which one should I go by? Is it the temperature of the glass or the temp of the inside firebox or the temp of the metal outside (measured by the magnetic thermometer) that matters?

I guess I don't know if what I'm thinking is a normal "secondary burn" is really the "opening of the gates of hell". Thanks.

 

[Grisu]

Point the IR thermometer from about 3" away just above the door in the center. The temp in that spot is slightly below the stove top temp in my PE Super. When the temps climb above 700 F there I turn the blower up a bit to make sure the insert does not get too hot.

A "normal" secondary burn is flames coming from the top baffle and glowing coals/wood with little flame in the bottom of the firebox. When you see fire everywhere even with the air closed then you are about to get a runaway fire.

(some are really long and only fit EW)

Sure you have a Summit? Longer pieces should rather fit N-S than E-W.

 

[PhatWood]

Thanks Grisu. I have been measuring the temperature with the magnetic thermometer in the spot you suggested I check with the IR thermometer. When I compare the 2 thermometer readings at that spot, they're both pretty similar. So, are the "ideal burning temps" the temperature inside where the flames are, or the temperature of the metal on the outside of the firebox?

I definitely have a PE Summit insert and you're correct that it is longer than it is wide. I guess what I meant to say about the very long pieces that I put them in along the diagonal when they were too long to be NS.

 

[Grisu]

Thanks Grisu. I have been measuring the temperature with the magnetic thermometer in the spot you suggested I check with the IR thermometer. When I compare the 2 thermometer readings at that spot, they're both pretty similar. So, are the "ideal burning temps" the temperature inside where the flames are, or the temperature of the metal on the outside of the firebox?

An IR thermometer measures radiant heat which can vary wildly within a firebox as flames move. To get anything reliable and comparable to other members here you need the stovetop temperature or a similar spot.

I definitely have a PE Summit insert and you're correct that it is longer than it is wide. I guess what I meant to say about the very long pieces that I put them in along the diagonal when they were too long to be NS.

Just teasing a Newbie a little bit. Diagonally I can fit in 23" pieces if they are not too thick. I know that so well because above that I need to get the chainsaw out to cut them to length again. I rather burn them without the extra work.