I just THOUGHT I knew how to burn my TL300

[MishMouse]

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Since pictures do not show actual distance, is the stuff that is located behind and on the right hand side of your stove set within the proper clearances?

As to flue temps, if you have a good draft you should be able to run it on notch 1 or even all the way off without having issues.
Sometimes when I have a good load going with a really strong draft, if I have my primary set at 2 or above my flue temps do stay a little on the high side. 350-400on a double wall pipe. But, when I cut it down to 1 or off it drops off between 150-250. So once your load gets going and the AB is engaged, you may have to run it on either 1 or off.

If excessive draft is the issue here is a link to some info that may help: (broken link removed to http://www.chimneysweeponline.com/hoxdraft.htm)

 

[branchburner]

what temp it would go to, if I did not have the alarm,,and go turn air down and work to get stove cooled when it happens.

I agree with the others, try burning with no primary... the only way you are going to find out how well that works with your setup is to try it. With my stove, the difference between setting the air at 0 or at 1 or 2 does not make a huge difference in flue temps, however.

Just to be clear and make sure we're on the same page, does the TL300 have 16 notches like the Oakwood? When I am burning at "2" it is with the air open 1/8, for example.

 

[razerface]

Just to be clear and make sure we're on the same page, does the TL300 have 16 notches like the Oakwood? When I am burning at "2" it is with the air open 1/8, for example.

no, our stoves are not the same. I hace 3 notches to the left of center on the adjustment, and 1 more notch slightly to the right of center for total of 4. Then there is a smooth space that probable equals 3 more notches farther to the right. I'll get a pic tonite when i get home. My 2nd notch probably is the same as your 4th or 5th or 6th notch since you have 16. I have never seen the Oakwood in person, so I am guessing

 

[razerface]

I agree with the others, try burning with no primary... the only way you are going to find out how well that works with your setup is to try it.

i know my wife left it on no primary air when it overheated the flue on her,, while waiting on me to come home and fix it,,,and it coated about 1/2 the glass with creosote, but i will expermint with it.

 

[razerface]

Since pictures do not show actual distance, is the stuff that is located behind and on the right hand side of your stove set within the proper clearances?

As to flue temps, if you have a good draft you should be able to run it on notch 1 or even all the way off without having issues.
Sometimes when I have a good load going with a really strong draft, if I have my primary set at 2 or above my flue temps do stay a little on the high side. 350-400on a double wall pipe. But, when I cut it down to 1 or off it drops off between 150-250. So once your load gets going and the AB is engaged, you may have to run it on either 1 or off.

If excessive draft is the issue here is a link to some info that may help: (broken link removed to http://www.chimneysweeponline.com/hoxdraft.htm)

yes, everything is good on clearances. I have a manometer ordered to check and measure my draft, but it has not arrived yet. Hopefully soon!

I may have to send it around to you guys to measure yours so I can compare,,or I won't have any base line other the the. manual numbers

 

[Seasoned Oak]

How about contacting your dealer about Internal flue temps? Be warned beforehand that harman dealers are notorious for lack of service after the sale. Or you could email the techs at harman.
I still think you stove is operating normally and your over analyzing it. Dont forget that the AB is burning cherry red at 1500+ just a few Ft below where your taking your measurement so i would think 1200 is about right.

 

[branchburner]

no, our stoves are not the same. I have 3 notches to the left of center on the adjustment, and 1 more notch slightly to the right of center for total of 4. Then there is a smooth space that probable equals 3 more notches farther to the right. I'll get a pic tonite when i get home. My 2nd notch probably is the same as your 4th or 5th or 6th notch since you have 16. I have never seen the Oakwood in person, so I am guessing

Well that's good to know! What that means is you have been doing "medium" burns rather than low burns. My air control is simply a slider, so the notches are just markings that allow me to gauge if the air is 1/2 open, 1/4, etc. You should be able to burn at 0 or 1 with good heat output, and get longer burns. You may get some dark glass at 0 (maybe due to the ash you are adding?) but it will burn off when you reload at higher air. If your wood is not dry enough, that would explain why you can't get clean glass or do low burns successfully.

That said, it is still odd to get such a spike in flue temps hours later into the burn, even at a medium air setting. In theory, the stove should not be even close to overfire at that setting after it's been stable for a few hours. It has never happened to me, though I do have a smaller firebox and shorter flue. The only thing that occurs to me is that with your stove and wood, the peak secondary combustion is delayed and the effects of too much air don't show themselves until you're quite a bit further into the burn. This would make sense (I think) if your wood is not fully seasoned: the early part of the burn is drying out the wood enough so that the major out-gassing and heat production in the AB is taking place much later. So you should definitely try burning lower and see how it goes.

I would try to watch what happens during an entire burn cycle during the day to get a better feel for how the stove is behaving and the heat it's throwing, and how much smoke is coming from the stack during the cycle. I would also suggest doing some loads of wood that you are 100% sure is <20% MC, as in two years old or kiln dried. You might see a very different burn cycle and temperature profile compared to what you have been seeing. Fully dry wood should allow you to burn smoke-free with your primary fully shut and steady cruising temps on both stove top and flue, with no spikes.

 

[branchburner]

i would think 1200 is about right.

But why 1200 and rising 3 hours into the burn? Seems like they should stabilize and drop a bit well before that.

 

[MishMouse]

I am starting to think this is the reason why my installers/sweeps told me not to install an internal thermometer on my double wall pipe.

For me I think I am ok as long as I keep the temp on my double wall pipe below 500. For me, off the stove the pipe goes up around 6" then takes a 45 angle. I measure the temps about 12" up on that 45. The flames tend to hit that area of the pipe so that it gets the hottest which is why I measure in this spot.
About 6-12" above that I have another thermometer and the temps on it is about 200less.

Though I do have to mention that I did ruin my pipe by letting it get to hot upon startup, this happened when I wasn't following the procedures I mentioned in one of my prior posts. A few times the temp on my double wall spiked the thermometer and that caused damage to the double wall pipe and the class A HT pipe. The temps in the pipe at the spike must have been well over 2000to cause the damage that happened. Now I put it into AB when it reads between 300and 350.

 

[razerface]

How about contacting your dealer about Internal flue temps? Be warned beforehand that harman dealers are notorious for lack of service after the sale. Or you could email the techs at harman.
I still think you stove is operating normally and your over analyzing it. Dont forget that the AB is burning cherry red at 1500+ just a few Ft below where your taking your measurement so i would think 1200 is about right.

99% of the time, it runs at 650-780sometimes stretching into the 800's but always dropping back down. These are cruising temps, unrelated to start-up or reloading fires .


I will email Harman and see what they say. The dealer looked at me like i was a was from mars when i asked them.

 

[MishMouse]

But why 1200 and rising 3 hours into the burn? Seems like they should stabilize and drop a bit well before that.

What almost sounds like happened is something increased the draft.
Either a failing gasket somewhere in the system, a change in the weather causing a stronger downdraft or maybe the gunk on the cap caught fire.

 

[razerface]

But why 1200 and rising 3 hours into the burn? Seems like they should stabilize and drop a bit well before that.

that is exactly my problem. The burn stabilizes,,,burns great,,,then without anyone touching the stove,,,goes wild and gains temp. It is not predictable which load or when it will happen. The ONLY common thing so far,, is every time, it has been a "stuffed to the gills" load, and approx 2-3 hours into the burn. I am thinking there may also have been some of the greener ash in all the bad loads. I will pay more attn to that.

The ash is 25-27, the oak is 18-20

 

[branchburner]

The ash is 25-27, the oak is 18-20

I'd pass on that ash and see how the loads of pure oak go

 

[razerface]

I'd pass on that ash and see how the loads of pure oak go

i can do that. Remember, there was also ash in loads that did NOT go hot. That was an interesting theory of the ash finally getting dry enough to burn on top of a hot load,,,and poof! Run away!

 

[branchburner]

The other related theory, sort of like the MishMouse idea that gunk on the cap caught fire and created draft, would be that you have been having an occasional mini-flue-fire, where some creosote build-up in the pipe is getting lit off and suddenly sending the temps up. I doubt that would happen just due to an occasional piece of green-ish wood, but might happen if your AB repeatedly is not actually firing until long after you close the bypass, or is stalling out. This could happen even with seasoned wood if the coal bed was not deep enough, air/bypass shut too soon, shoe opening blocked by a split, etc.

 

[razerface]

I can usually see the ab glow or flames coming out the sides back by the shoe. I do not stop opening the damper and restarting the fire until the AB is constant when I close the damper. I threw a pic of my air control , view straight down at it, so you can relate to my notches.

Cap is pretty clean. I did a cleaning a week or so ago

 

[Seasoned Oak]

You must have just started the stove to set the air that high. Its more tricky to operate this stove if your not around to turn the air down once the whole load is glowing. Dont fret over a little soot on the glass. All that is important is if the AB is lit up. I purposely load my stove so i can see right into it. Internal flue temps will be all over the map on most stoves.As long as you can maintain 400 or more stovetop with the AB still lit up,you can run it all the way left. You will get longer burn times and lower stack temps if you do.

 

[razerface]

Good morning! I slept in this morning. I knew you would mention that air position! It was on the second notch, but I slid it over to be sure the notch showed in the pic for branchburner.

I want to try a load today with it all the way to the left. I'll be home all day so it is a good time to try.

 

[razerface]

. All that is important is if the AB is lit up. I purposely load my stove so i can see right into it.

Do you look down one side? There are not always flames visible on the side right? Sometimes I have the flames shooting from the angled channels, especially as soon as I engage the AB, but mostly just watch for both or either side glowing brightly, reflecting off the sidewall in the back corners.

 

[Seasoned Oak]

I made a tunnel out of the wood so i can see the whole area. During the first paret of the burn it looks like a dozen torches with flames coming from every hole,later the whole ceramic structure glows cherry red. IF you are getting soot on your glass i dont think you have excessive draft,that only occurs on my stove when the draft is not that strong.

 

[razerface]

I saw it do it last night!

I was burning with the air all the way shut down. It had been cruising, almost 3 hours after reload, putting out good heat,,,the I heard it happen! The stove started roaring, just like when you engage the AB on a hot flue, but much louder! I walked over and looked in the stove,,,the AB was blowtorching,,,,I don't mean small either,,,,it was big,hard blowing torches on both sides, about twice as strong as normal hot ones. Loud!

With the air shut completely off, the temp in the flue rose to 1234 from 781 in less then 1 minute! I never touched anything, it lasted 7 minutes, and the torches vanished. The stove went back down to 822. If I had been burning on the 2nd or 3rd notch, that would have been the extreme flue temps my alarms were recording, but since I had the air completely shut down, it held the temps down this time.

Why is this?

 

[branchburner]

With the air shut completely off, the temp in the flue rose to 1234 from 781 in less then 1 minute! I never touched anything, it lasted 7 minutes, and the torches vanished. The stove went back down to 822. If I had been burning on the 2nd or 3rd notch, that would have been the extreme flue temps my alarms were recording.

Why is this?

Sounds like you are experiencing what has been described on VC Everburn threads as a "thermonuclear event". Maybe the secondary combustion is hitting a "sweet spot" where a sudden increase in the outgassing causes the fire to get hotter, the hot fire creates more draft, in turn making the fire burn even hotter. Basically, the same feedback system that causes any fire to get hotter.

It's almost like the fire is pouring gasoline on itself, that gasoline being extra air. The fire gets temporarily hotter until the source of that extra fuel dries up. But why a sudden increase in air that stops after seven minutes? This is hard to say.

The good news is:
- you can burn with the air shut completely off
- when you did, the temp spike was not up to alarming levels
- the temp spike was self-limiting, requiring no intervention

But the fact that a few hours into the burn your "normal" flue temps are around 800f, with primary air fully shut, suggests to me the draft is a bit stronger than you need to get a long, efficient and sustained secondary burn. I'd want lower flue temps, in the 500-700f range.

 

[Seasoned Oak]

Sounds like you had a short chimney fire that lasted 7 minutes.Or a windy spell outside that pulls hard on your draft for some reason. If you are getting too much draft from time to time i can imagine that it would pull the hot gasses up into your flue before the stove had time to absorb the heat. Although this is one of the cleanest burning stoves you can find,outside of a cat stove. So i cant imagine anything building up in the flue.
Iv had my stove in 2 different houses, one with 25Ft flue and now with a 35Ft+ flue and dont have this situation at either.

 

[razerface]

Sounds like you had a short chimney fire that lasted 7 minutes. Although this is one of the cleanest burning stoves you can find,outside of a cat stove. So i cant imagine anything building up in the flue.

That chimney is clean. Guaranteed.

 

[MishMouse]

How does your cap look, maybe something caught on it?
I had a extended jet sound that happened about an hour into a normal burn, I looked at the cap and some of the stuff at the top was burning.
Not, a true chimney fire, just more of a cap cleaning event. Since you have such a tall chimney and it has been unusually cold stuff could be building up in your cap, then catching fire causing an increased draft. Next time it happens go outside and look at you cap and see if anything unusual is going on.
The cap clogging issue occurs mainly when I burn pine and it is less then -15outside.