I just THOUGHT I knew how to burn my TL300

[mellow]

Mine is AT200CHIM, which looks just like the AT100. I think they packaged the probes and buzzer with AT100 and gave it a new p/n

On edit: i see the AT200 has external buzzer and low temp(reload) alarm the TL100 does not have.

AT200 has the different thermocouple connector and port for external buzzer, that is the only difference. I recommend the AT-100 due to the built in alarm is loud enough for most and it is cheaper.

Both have AL and AH settings.

 

[razerface]

AT200 has the different thermocouple connector and port for external buzzer, that is the only difference. I recommend the AT-100 due to the built in alarm is loud enough for most and it is cheaper.

Both have AL and AH settings.

The AT100 only has AL and AH. If you set AL to 880 and AH to 900,,,that is 1 alarm, which would be on at 900deg,, off at 880deg.

The AT200 has A1L and A1H, A2L and A2H to set, which is 2 separate alarms.
If you read the online instruction manual for both of them, the AT 200 has 2 different temp ranges you can set, where the AT100 only has 1. The AT200 lets you set a low temp alarm for when your stove needs reloaded, or goes cold with the second alarm.

I needed the external buzzer cause I am hard of hearing. I ran it up the stairwell and mounted it upstairs. My wife rolled her eyes on that one,,,, I reminded her how funny she'll look when they stick like that!

 

[mellow]

Ahh, overlooked that. I am only interested in the single alarm so I know if my stove is running away on me.

 

[branchburner]

Does that mean a surface pickup would be better then the probe if it was a fast thermocouple type? Then not worry about air temp,,,just pipe?
.

Don't think it matters, so long as you can translate the probe temp into terms of pipe temp, and are working from the same apples-to-apples standard as others. For example, I can't directly compare my flue temp to others because my setup in a fireplace limits my mag placement to about 6" up the pipe from the stove, which will show higher temps than those using a reading higher on the pipe.

Consider it this way, too, that the temp in your AB needs to hit about 1100f before secondary even kicks in (how hot is actually DOES get after that, I don't know... anybody?) -- but while it hits 1100f, its pretty clear the outer surface temp of the stove won't be nearly that hot... and where you take the temp on the stove top may vary greatly at different stages of the burn and with different stoves. Precision is not so important as the general: not too hot (no glow), not too cool (no creo).

 

[Seasoned Oak]

I look at the 6Ft of single wall pipe above the stove as just another heat exchanger. By the time the pipe goes into the chimney it has given up most of the heat it had at the stovetop.
probably down around 200F, even though it may be between 400 and 500 right at the stove exit.

 

[1kzwoman]

I look at the 6Ft of single wall pipe above the stove as just another heat exchanger. By the time the pipe goes into the chimney it has given up most of the heat it had at the stovetop.
probably down around 200F, even though it may be between 400 and 500 right at the stove exit.

Your post holds true with temps I see with my stove using mag & red dot thermometers. Total stack about 18'

 

[razerface]

it certainly sounds like this stove should run a single wall pipe off the stove. Get more heat and cool the hot flu down, allowing me to burn hotter on the stovetop. I will change and see what happens to my creosote. I cleaned last week and had only some grey dust and a couple small black pieces from the cap. I'll have to keep thinking about the pipe dampner.

 

[blazincajun]

With a 34ft chimney and very strong draft, you might install a pipe damper as an extra element of draft control (while the other method is to try to adjust secondary air input with a modification, not recommended as it voids the warranty). Even if you rarely or never use it, it might be nice to have the option.

Try single wall pipe to chimney. You may need to reduce the width of you chimney down a size. Usually done while actually measuring draft pressures according to technical specifications on long chimneys. Andrew

 

[razerface]

Try single wall pipe to chimney. You may need to reduce the width of you chimney down a size. Usually done while actually measuring draft pressures according to technical specifications on long chimneys. Andrew

my chimney is round.

 

[Seasoned Oak]

it certainly sounds like this stove should run a single wall pipe off the stove. Get more heat and cool the hot flu down, allowing me to burn hotter on the stovetop. I will change and see what happens to my creosote. I cleaned last week and had only some grey dust and a couple small black pieces from the cap. I'll have to keep thinking about the pipe dampner.

No way would i put a damper on my flue pipe. This stove likes a strong draft. Its also very controllable. Only way mine overheats is if i forget to close the bypass .Once closed you can turn down the air far enough to give you an 18 hour burn ,PROVIDED you have a strong draft. IF you operate this stove correctly with fairly dry wood creosote will be a thing of the past. It has one of the lowest emission levels iv ever seen on a conventional wood stove.

 

[razerface]

i have never got more then 8-9 hour burn, with a good hot coal bed left over that would have gone another hour or maybe 2. I left the house at 6am, with the air in 1.5 notch. I'll see when I get home, but before I left I saw brown on the glass,,which i never get when i burn over the second notch.

Seasoned, do you have an OAK on yours?

 

[Seasoned Oak]

i have never got more then 8-9 hour burn, with a good hot coal bed left over that would have gone another hour or maybe 2. I left the house at 6am, with the air in 1.5 notch. I'll see when I get home, but before I left I saw brown on the glass,,which i never get when i burn over the second notch.
Seasoned, do you have an OAK on yours?

Sort of. I have an underground pipe that carries power and water to my garage. it pulls air from the garage then underground for about 100 Ft so its closer to ground temp and not as cold as pulling straight from outdoors. As far as burn time, my record is 27 hours with a full load of seasoned oak and still enough hot coals for a reload. Usable heat time is probably somewhere around 12-15 hours. Definitely an overnight burner.

 

[branchburner]

Once closed you can turn down the air far enough to give you an 18 hour burn ,PROVIDED you have a strong draft .

Maybe better stated as " Once closed I can turn down the air far enough to give me an 18 hour burn , because have a strong draft that is not too strong." You are describing your stove/flue, not that of the OP. YMMV.

If you are getting very long burns at normal or low flue temps, I can't see why you would put a damper on your flue pipe. On the other hand, if you were getting short burns at high flue temps, with primary air shut, I can't see why you wouldn't consider a damper on your flue pipe.

The same stove model performs differently with various flue setups. The fact is, stronger draft past a point -- if too strong -- will give a hotter and shorter burn time, not a longer one. Never heard of anyone having extra long burn times in conjunction with extremely high flue temps and possible overfires!

 

[Seasoned Oak]

THe harman manual calls for no less than .10 using a magnahelic or other pressure gauge
which reads in inches of water column (in. H20). With a brisk fire and air control on high and .06 with the air control setting on low .
Interestingly it does not state what would be considered too much.
Before i would consider any kind of damper in the flue ,i would measure your draft to see if indeed you do have too much. 'No where in the harman manual did i find any recommendation of installing a flue pipe damper.

 

[razerface]

I will work on getting my draft measured. Is that something I can do , or are the tools expensive?

I just got done playing. I have decided that 1200 is my number where I want my high alarm to go off. I may go higher later.

The mag gage reads on the hot line when the stove is at 1200. I had to move it 4 inches down closer to the stove to make that happen. Just for fun. In the pic it isn't on the hot side. Just showing the gage that I made match the digital and my chosen temp.

I also pulled the probe when my air was reading 1223. I pulled it from the inner pipe, but did not pull it from the outer wall. Then I cocked it at an angle and held it against the inner wall. It read 537, less then half of the inside air temp. When I put it back in the pipe, it went to 1257, so I considered that pretty steady.

 

[razerface]

Digital temp has held steady at around 783, inner pipe is 298, outer pipe is 280. I am surprised to see the inner and outer that close. Maybe a mag can be used on a double wall. The double wall is not insulated.

 

[Seasoned Oak]

Digital temp has held steady at around 783, inner pipe is 298, outer pipe is 280. I am surprised to see the inner and outer that close. Maybe a mag can be used on a double wall. The double wall is not insulated.

I suspect your temps are average. Dont forget that your AB ceramic is glowing cherry red just a few feet below,probably in excess of 1500F. I do know they stopped making the AB structure out of cast iron in th eolder models as it was cracking from the heat,they switched to this new fibre material. So at what temp does cast iron crack?

 

[branchburner]

Nowhere in the harman manual did i find any recommendation of installing a flue pipe damper.

Maybe not, but my Oakwood manual says : "Overdraft can be caused by a very tall chimney, and can cause overfiring... signs include rapid fuel consumption... avoid overfiring... caused by too much air flowing through the stove too quickly... if you notice signs of overfiring reduce the air supply to the fire".

If primary air is already shut, I can only think of three ways to reduce the air supply to the fire:
- plug the secondary air holes
- kill the draft by opening the front door
- slow the draft by way of a pipe damper

So if a chimney is pushing 40' it might make sense to downsize to a 5.5" liner, but putting in a pipe damper is heckuva lot cheaper, and gives the option of adjusting flow depending on conditions (not to mention letting you burn a smallish fire with bypass open in warmer weather). Personally, I'd go with making the secondary air adjustable... might even get around to trying it one of these days!

 

[razerface]

I ordered a manometer to check my draft. 60 bucks for a digital on eBay.

Last night, at midnight, about 2 hrs after loading, the alarm went off. It was 1131 in the flue by the time I got to the stove, (alarm at 1070) and after shutting the air completely off, opening and closing the top a few times, it kept rising until 1360.

It stayed above 1000 for the next half hour no matter what I did, with visible flame all over the wood. Was not extremely hot flame, as it had creosote all over the window.

I sat with it for over an hour till it was at 880 deg, and seemed stable. I want to blame it on lightweight wood that burns too fast. I vaguely thought about it while loading, but loaded anyway, figuring it would get up in middle of the night and put more in if it all burned up. That theory is supported by the fact that the stove was cold at 5am when the low alarm went off.

Or my big draft ate the wood with over fire. Sigh,,,,

 

[branchburner]

It was 1131 in the flue by the time I got to the stove, (alarm at 1070) and after shutting the air completely off, opening and closing the top a few times, it kept rising until 1360.

Where was your air setting for the 2 hrs after loading?

 

[Seasoned Oak]

I have a tall (close to 40Ft) chimney and a strong draft on my harman but there has never been a fire i could not control with the primary air lever,even when burning large amounts of dry pine. When closed all the way there is no flame at all in the firebox,only a glowing afterburn chamber. I still get long burns. The stronger draft simply allows me to use a lower primary air setting.

 

[razerface]

Where was your air setting for the 2 hrs after loading?

2nd notch from left

 

[razerface]

When you guys are in the middle of a burn, what does it look like?

I just came home to check mine cause I am scared of it right now. I loaded it to the top before I left at 7:30am, on notch 2.

When I checked, at around 11am, it showed the splits still stacked up past the window, and all of them burning with yellow flames,,clear to the top of the load. Creosote on the window. I opened the top door and the whole load is burning together, all splits were coaled and glowing from top to bottom. When I poked with the poker, the pile collapsed to half it's size.

I was under the impression that the load would burn from the bottom, upwards. Not true?

 

[razerface]

Before i would consider any kind of damper in the flue ,i would measure your draft to see if indeed you do have too much.

Have you had your measured?

 

[Seasoned Oak]

Have you had your measured?

No need as i know i dont have too much. It seems the stronger the draft the more likely you can run the stove on minimum air. When i had this same stove on a shorter flue i could not turn the air down past 3 notches from the left. If the fire slows too much the AB goes out. Somewhere just below 400 stovetop