Hello Folks,
OP back again.
This is a bit of an epic post, so stick with me.
So I agreed with those of you who figured it was a bit jumping to conclusions to try and fully diagnose off one load of poplar (the previous test-fire). Especially seeing as how I didn't load it as I usually would for a cold stove (with some scrap between the kindling and cordwood). I must have misunderstood, I thought we were doing some weird test-fire without any scrap to take that aspect out of the equation. I think we can more or less ignore those previous results, considering what happened with the poplar load below.
Test fire #1: "25% scrap, 75% poplar" as suggested by Jags
load consisted of paper, bark, 4 pieces foot-long pieces of scrap 2x4, 4 normal-sized splits of poplar
In the last test-fire, we had already established that the poplar didn't produce black-smoke and would quit smoking completely once up to temp, so I didn't bother running in and out to check the chimney as often, same results as the last test burn, some smoke at the start-up, but once up to temp, no problems, only heat-mirage at the cap.
0 minutes: lit the fire
6 minutes: stove temp (measured by IR thermo at upper left-hand corner of griddle) up to 350 F. Stove is chugging air hard, so I shut off the ignition air.
8: 500 F so took the primary air down to 5-10%
10: 525 F
15: 600 F so took the primary air down to minimum
17: 650 F
23: 665 F
27: 685 F
30: 700 F
34: 725 F
36: 750 F Fire was drawing like crazy, flames whipping around, despite being choked back as far as possible. Since the temperature was still climbing, I became worried about over-firing the stove, but with the primary air already at minimum, my only option was to close the window and induce a negative-pressure in the basement, so I did. It helped immediately with the draw, and the temperature began to fall soon after.
40: 765 F
43: 725 F
45: 700 F
1 hour and 25 minutes: 500 F
So I don't know if this is a normal situation with poplar of 18% moisture (this is only the second time I've burnt this species), but I was concerned over the possibility of over-fire. I know Jags, you said to keep it below 700 F. Made me wish I still had the flue-damper installed. Also makes me wonder what would have happened had I already had the new combustion-air to the furnace and fresh-air intake for the basement already installed (happening this Saturday, to resolve the negative pressure issue), and thus no ability to close the window and cut air to the stove further.
- What is the max safe temp for the stove?
- What peak temperature should I be shooting for?
- Should I have been able to control the fire more easily or is this the way it goes? (Had I been loading onto an established coal-bed, say before turning in for the night, I could easily have packed the stove way more. Does this mean I can't load the stove fully with poplar alone? Need to mix in some Oak etc?).
- Suggestions / insights I'm not cluing into see as how I'm a first-time burner?
I also did another test-fire with the 9-12% moisture pine:
Test fire #2: Can I get the pine to burn without black smoke?
After having "burning-tires" amounts of black smoke when burning a load of only smaller pine-splits, despite good temperatures reached, I wanted to see if I could burn smaller numbers of larger pieces of pine and have a clean burn (thus testing out the excess-gases-condensating theory).
Load was paper, bark, two 15" pieces of scrap 2x4, and 2 larger-sized pine-splits.
Here is what happened:
0 minutes: lit the fire.
5 minutes: 250 F
8 minutes: 425 F, drawing well, but not chugging like the previous time. But up to temp so I cut the ignition air. Some grey smoke at the chimney still.
11 minutes: 475 F
12 minutes: 500 F
14: 525 F. Less grey smoke at chimney, but some still visible. Cut the primary air down to 5 - 10%.
20: 550 F. No smoke at the chimney, only heat-mirage.
25 minutes: 535 F. Still clean-burn at the cap.
So correct me if I'm drawing the wrong conclusion, but looks that the previous times with black-smoke was likely due to the 2ndary tubes being overwhelmed with excess particulate / gases?
Is this what the installer was talking about regarding the pine being "punky": Too dry and burns too fast?
What else should I be pulling out of this test-fire?
Suggestions for future loads, combinations of species to balance things out further? Or test things further?
I'm just glad I've found a way to cleanly burn that cord and a half of pine I have sitting in the garage.
Thanks for reading this epic post,
And being so generous with your time and experience this past week.
OP back again.
This is a bit of an epic post, so stick with me.
So I agreed with those of you who figured it was a bit jumping to conclusions to try and fully diagnose off one load of poplar (the previous test-fire). Especially seeing as how I didn't load it as I usually would for a cold stove (with some scrap between the kindling and cordwood). I must have misunderstood, I thought we were doing some weird test-fire without any scrap to take that aspect out of the equation. I think we can more or less ignore those previous results, considering what happened with the poplar load below.
Test fire #1: "25% scrap, 75% poplar" as suggested by Jags
load consisted of paper, bark, 4 pieces foot-long pieces of scrap 2x4, 4 normal-sized splits of poplar
In the last test-fire, we had already established that the poplar didn't produce black-smoke and would quit smoking completely once up to temp, so I didn't bother running in and out to check the chimney as often, same results as the last test burn, some smoke at the start-up, but once up to temp, no problems, only heat-mirage at the cap.
0 minutes: lit the fire
6 minutes: stove temp (measured by IR thermo at upper left-hand corner of griddle) up to 350 F. Stove is chugging air hard, so I shut off the ignition air.
8: 500 F so took the primary air down to 5-10%
10: 525 F
15: 600 F so took the primary air down to minimum
17: 650 F
23: 665 F
27: 685 F
30: 700 F
34: 725 F
36: 750 F Fire was drawing like crazy, flames whipping around, despite being choked back as far as possible. Since the temperature was still climbing, I became worried about over-firing the stove, but with the primary air already at minimum, my only option was to close the window and induce a negative-pressure in the basement, so I did. It helped immediately with the draw, and the temperature began to fall soon after.
40: 765 F
43: 725 F
45: 700 F
1 hour and 25 minutes: 500 F
So I don't know if this is a normal situation with poplar of 18% moisture (this is only the second time I've burnt this species), but I was concerned over the possibility of over-fire. I know Jags, you said to keep it below 700 F. Made me wish I still had the flue-damper installed. Also makes me wonder what would have happened had I already had the new combustion-air to the furnace and fresh-air intake for the basement already installed (happening this Saturday, to resolve the negative pressure issue), and thus no ability to close the window and cut air to the stove further.
- What is the max safe temp for the stove?
- What peak temperature should I be shooting for?
- Should I have been able to control the fire more easily or is this the way it goes? (Had I been loading onto an established coal-bed, say before turning in for the night, I could easily have packed the stove way more. Does this mean I can't load the stove fully with poplar alone? Need to mix in some Oak etc?).
- Suggestions / insights I'm not cluing into see as how I'm a first-time burner?
I also did another test-fire with the 9-12% moisture pine:
Test fire #2: Can I get the pine to burn without black smoke?
After having "burning-tires" amounts of black smoke when burning a load of only smaller pine-splits, despite good temperatures reached, I wanted to see if I could burn smaller numbers of larger pieces of pine and have a clean burn (thus testing out the excess-gases-condensating theory).
Load was paper, bark, two 15" pieces of scrap 2x4, and 2 larger-sized pine-splits.
Here is what happened:
0 minutes: lit the fire.
5 minutes: 250 F
8 minutes: 425 F, drawing well, but not chugging like the previous time. But up to temp so I cut the ignition air. Some grey smoke at the chimney still.
11 minutes: 475 F
12 minutes: 500 F
14: 525 F. Less grey smoke at chimney, but some still visible. Cut the primary air down to 5 - 10%.
20: 550 F. No smoke at the chimney, only heat-mirage.
25 minutes: 535 F. Still clean-burn at the cap.
So correct me if I'm drawing the wrong conclusion, but looks that the previous times with black-smoke was likely due to the 2ndary tubes being overwhelmed with excess particulate / gases?
Is this what the installer was talking about regarding the pine being "punky": Too dry and burns too fast?
What else should I be pulling out of this test-fire?
Suggestions for future loads, combinations of species to balance things out further? Or test things further?
I'm just glad I've found a way to cleanly burn that cord and a half of pine I have sitting in the garage.
Thanks for reading this epic post,
And being so generous with your time and experience this past week.
Several have commented that the IR likes to run, and with those loads... 
As mentioned, you'll get a feel for when to start cutting the air to keep the new load under control and avoid getting too much wood gassing. As also mentioned, about the time you think you have it figured out, you'll get the mystery load that goes high on ya, so be ready for that. 
