Help with draft/ possible overfire issue

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Wood_Burner56

New Member
Nov 14, 2021
5
East Coast
Hello all. Searched the forum and got some great info germane to my situation but not entirely. Last year installed a True North TN19 in a recessed chimney, and had sweep put in a an insulated liner. Big run of 30 ft. Only burnt for a week or so so I did not have any thermometer on the stove top. Found on very quickly that we were losing a ton of heat up the chimney void as there was no block off plate installed. Because of the way the stove is recessed a traditional block off plate was not really possible. Wanting to help secure more heat but not risk overheating, I had a stainless steel box fabricated that surrounds the stove and slides in around the pipe. I then stuffed roxul between the box and the chimney and into the void as best I could. Threw a magnetic stove pipe thermometer on the stove top and started burning. Since then we’ve had a few fires where I’ve loaded it full (and not with a hot stove as I knew that was a no no,) and the thermometer has maxed out at 850*! It seems like with the damper completely closed the stove will simply still burn with too much air, and this coupled with the secondaries makes it get way hot. Can be burned with smaller loads at 5-600 on stove top thermometer. However I also invested in an infrared gun which reads about 80-100* cooler than the magnetic thermometer. What do you folks think is the issue here, if at all. At no point has either the stove top or flue collar glowed red, And aside from paint curing I haven’t really smelled hot metal. Any recommendations for reducing the draft on the stove? I don’t really know where the secondary air comes in? If need be I could pull the insulation out. Does the fire in this post seem way to rapid for the damper completely shut down?

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begreen

Mooderator
Staff member
Nov 18, 2005
91,319
South Puget Sound, WA
The stove needs a key damper at the flue collar. The TN19 is an easy breathing stove and the draft in a 30' insulated liner is going to be extra strong. The damper will allow you to reduce the draft once the fire is burning well. Other than that, burn large splits, tightly packed and shut down the air as quickly as possible without smoldering the fire.
 
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Wood_Burner56

New Member
Nov 14, 2021
5
East Coast
Very much obliged for the response. At some point we will contact the gentleman who installed the flue and see if he can do that. Only issue is the amount of clearance. I've posted a pic of the inside of the chimney after the heat saving modifications, which I can redo if need be. Very little space there now but without the face plate I threw on and the steel block off box theres about 4" of space between the top of the stove and the masonry, so not sure how easy that would be but that's why we hired a pro. I read one of your posts on here I believe just giving an overview on EPA stoves, which was extremely informative, so thank you. Do you think the stove top thermometer or the infrared reflects the actual temp of the stove top? I've read PE stoves tend to get into the fire breathing territory, and as I said I haven't seen and glowing or smelled any hot metal so that's good haha, just don't want to induce metal fatigue.
The stove needs a key damper at the flue collar. The TN19 is an easy breathing stove and the draft in a 30' insulated liner is going to be extra strong. The damper will allow you to reduce the draft once the fire is burning well. Other than that, burn large splits, tightly packed and shut down the air as quickly as possible without smoldering the fire.22`

IMG_7955.jpg
 

begreen

Mooderator
Staff member
Nov 18, 2005
91,319
South Puget Sound, WA
The IR thermometer is more accurate.

I'm seeing a blocking piece of metal over the front of the stove. That may be having the opposite effect of not letting heat convect from behind the plate. I would remove that and see if the stove runs a little cooler.

Does the stove have a blower? That will cool the stovetop down by about 100-150º.

Is there a block-off plate up in the damper area of the fireplace?
 
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Wood_Burner56

New Member
Nov 14, 2021
5
East Coast
The IR thermometer is more accurate.

I'm seeing a blocking piece of metal over the front of the stove. That may be having the opposite effect of not letting heat convect from behind the plate. I would remove that and see if the stove runs a little cooler.

Does the stove have a blower? That will cool the stovetop down by about 100-150º.

Is there a block-off plate up in the damper area of the fireplace?
Yes, so it's actually a "box" fabricated from stainless steel that surrounds the stove, as there's not enough clearance for a traditional block off plate. The front plate is honestly just for looks, as the block off "box" is a lot uglier than a traditional plate as you can see it/insulation. Also a bit worried about dogs maybe trying to eat bits of roxul if it migrates out. Quite an irony if the block off device and insulation is in fact doing what I wanted and keeping heat from migrating up the chimney only to be blocked off by my aesthetic fix. No blower unfortunately as the fireplace was not deep enough to support it because it mounts in the rear. Very oddly small fireplace TBH even for an old house, and frankly I bought the stove because I got a hell of a deal on it but it really isn't perfect for this set up, sort of a tail wags dog scenario, but finding a nice rear vent stove with a 2 Ft3 firebox seems near impossible on our budget.
 

begreen

Mooderator
Staff member
Nov 18, 2005
91,319
South Puget Sound, WA
It sounds like the box is trapping heat. Remove the top panel and put a fan blowing room air into the box down low so that it circulates around the stove and out the top.

The stovepipe damper will tame it along with the previous suggestions.
 

Wood_Burner56

New Member
Nov 14, 2021
5
East Coast
It sounds like the box is trapping heat. Remove the top panel and put a fan blowing room air into the box down low so that it circulates around the stove and out the top.

The stovepipe damper will tame it along with the previous suggestions.
Thank you for the suggestions! I'll try to give this a go.
 

Wood_Burner56

New Member
Nov 14, 2021
5
East Coast
It sounds like the box is trapping heat. Remove the top panel and put a fan blowing room air into the box down low so that it circulates around the stove and out the top.

The stovepipe damper will tame it along with the previous suggestions.
One final question for you. Do you know if the secondary air for this stove can be accessed and restricted? I know some stoves can be damped down a bit more through the secondary air lever, don't know about this one though.
 

begreen

Mooderator
Staff member
Nov 18, 2005
91,319
South Puget Sound, WA
It's possible on most stoves. Whether it is the best solution or not depends on the situation.
 
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ABMax24

Minister of Fire
Sep 18, 2019
1,318
Grande Prairie, Alberta, Canada
One final question for you. Do you know if the secondary air for this stove can be accessed and restricted? I know some stoves can be damped down a bit more through the secondary air lever, don't know about this one though.

I've been down that road, it is absolutely possible to restrict the secondary air on a tube stove, but it's very difficult to get balanced properly on a tall chimney like yours, mine is 36ft and it was incredibly finnicky to tune. I spent a full season changing the amount of restriction on an almost weekly basis and it never really did work all that well.

I put in a flue damper, my stove is now stock and I'm not looking back, far simpler and the damper allows draft to be adjusted on the fly to suit variables like wind and outdoor temperature.
 
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planner steve

Burning Hunk
Dec 24, 2014
102
Northern Idaho
Hello all. Searched the forum and got some great info germane to my situation but not entirely. Last year installed a True North TN19 in a recessed chimney, and had sweep put in a an insulated liner. Big run of 30 ft. Only burnt for a week or so so I did not have any thermometer on the stove top. Found on very quickly that we were losing a ton of heat up the chimney void as there was no block off plate installed. Because of the way the stove is recessed a traditional block off plate was not really possible. Wanting to help secure more heat but not risk overheating, I had a stainless steel box fabricated that surrounds the stove and slides in around the pipe. I then stuffed roxul between the box and the chimney and into the void as best I could. Threw a magnetic stove pipe thermometer on the stove top and started burning. Since then we’ve had a few fires where I’ve loaded it full (and not with a hot stove as I knew that was a no no,) and the thermometer has maxed out at 850*! It seems like with the damper completely closed the stove will simply still burn with too much air, and this coupled with the secondaries makes it get way hot. Can be burned with smaller loads at 5-600 on stove top thermometer. However I also invested in an infrared gun which reads about 80-100* cooler than the magnetic thermometer. What do you folks think is the issue here, if at all. At no point has either the stove top or flue collar glowed red, And aside from paint curing I haven’t really smelled hot metal. Any recommendations for reducing the draft on the stove? I don’t really know where the secondary air comes in? If need be I could pull the insulation out. Does the fire in this post seem way to rapid for the damper completely shut down?

I have a PE Super 27 and construction looks similar. I have a tall chimney also and if I am not careful I can overheat. But I have a blower and with closing the damper I am able to avoid overheating. Put a blower on it and you will likely be able to avoid overheating and recover more of that heat. If that doesn't do it, then maybe add flue damper as next step?

Are there any downsides to having a flue damper? Maybe those who have gone that route can comment?