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Smoker Door Heat Loss Question

aggie09

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Joined Oct 14, 2021
I recently picked up a Johnson 24” t-pit. This is my first offset as I’ve mostly used a WSM and other charcoal cookers in the past. When fired up the first time I was surprised by the amount of heat loss from the doors. I took a video when there was still some white smoke and it seemed like more smoke was coming out of the doors than the actual stack. Is this amount of heat loss around the doors normal/expected on larger offsets? Here’s a link to the video I took: Thanks
 

Mr. Zorg

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Joined Aug 26, 2021
Depends on how well it was built WRT doors sealing. My vintage 24" diameter original Oklahoma Joe's Chuckwagon combination horizontal and vertical offset has little leakage along the horizontal door edges but significantly visible leaks along the vertical section door seams.

In practice I'm still able to maintain what I consider to be "good control" primarily using the firebox inlet register and occasionally using the swing away cover on the stubby stack when needed to get better control range at the firebox inlet air register.

So to me, the question is, how well do you feel your pit allows you to have, or not have, over your pit's hydraulics?
 

mike243

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I wouldn't worry about it in all honesty, if you didn't have a abundance of heat/smoke it would draft on out the chimney, you could add longer chimney tubes and seals every where but doubt id would help a lot for wood usage ect
 

daveomak

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If you take the time to seal ALL of the air leaks, you will have much better control of the CC temperature and use less fuel...
The only openings to atmosphere, ideally, is the air inlets on the FB door and the exhaust stack...

The lower inlet adds air to the fuel supply, adjusting the temperature in the Cook Chamber...
The upper air inlet moves heat from the FB to the CC... reducing fuel consumption and making for even temperatures across the cooking surface....
If there are air leaks in the "system", the "system" does not work properly...
Adjusting the smoker so there are NO AIR LEAKS will increase your smoking pleasure.... you will be "GOLDEN"...

Smoker Exh and Intakes 2.jpg
 

tx smoker

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This is my first offset as I’ve mostly used a WSM and other charcoal cookers in the past
Alright...for starters, this is not considered an offset smoker. A traditional offset has the firebox at the end of the cook chamber....hence "offset". The T-Pits are designed to be reverse flow from both directions and heat perfectly even from end to end and top to bottom. The heat can be adjusted end to end by shifting the heat deflector plate one way or the other thus damping down one end and opening the other end for more heat. I have my firebox set up differently so heat and/or smoke loss from there is not an issue. I have a custom stretched 2-door version of that same smoker and absolutely love it. Far and again the easiest to use and most efficient smoker I've ever had. When I got mine I did have smoke loss at the tops of the doors on the cook chamber. Took a minute to figure out why and turns out that it's the way he mounts the hinges. The circular pieces of steel welded to the CC which hold the hinge for the doors is about 3/32" thick and raises the top of the doors that far off the body of the CC. All I had to do was use some of the same gasket material that is used on the Big Green Egg. I ran the gasket material all the way across the tops of the doors and part way down each side and that totally sealed it. I wasn't getting any smoke or heat loss along the bottoms because the doors laid flat against the body of the CC and the gaps up the sides got larger as they went up due to the tops f the doors being raised off the body of the CC from the hinge mounts. Here are a few pics:
017.jpg

018.jpg


You can see how the tubular steel raises the door off the body of the CC
019.jpg

020.jpg

021.jpg

022.jpg

026.jpg


I also drilled some holes through both ends and installed brass plumbing fittings to run the temp probes through
027.jpg


Hope this helps answer some questions for you. To validate how much I love this smoker, I'm working with Chad right now to see about having a custom vertical unit built. We will see how that turns out but one way or another, I have a new smoker in the works. Lemme know if you have any additional questions.

Robert
 
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tx smoker

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Adjusting the smoker so there are NO AIR LEAKS will increase your smoking pleasure.... you will be "GOLDEN"...
Dave has spoken the gospel. In addition to all he and others have said, if there are "openings" or air leaks, they not only allow heat and smoke to escape, they will also allow wind to blow in. That can wreak havoc on trying to maintain steady temps. A couple dollars worth of that gasket material will solve all your problems. Please note however that I did not install it all the way around the doors, only where I saw smoke escaping. Some portions of the doors laid flat against the CC so there was no loss and no need for the gasket.

Robert
 

Smokin Okie

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Dave has spoken the gospel. In addition to all he and others have said, if there are "openings" or air leaks, they not only allow heat and smoke to escape, they will also allow wind to blow in. That can wreak havoc on trying to maintain steady temps. A couple dollars worth of that gasket material will solve all your problems. Please note however that I did not install it all the way around the doors, only where I saw smoke escaping. Some portions of the doors laid flat against the CC so there was no loss and no need for the gasket.

Robert
Amen.

I was told to not worry about the leaks on my Old Country Brazos, was told it just helps air flow. Was mostly people making apologies for OC's poor build.

And I followed that advise until I did a biscuit test and saw with my own eyes, how much cooler is was along the door side of the cooking grate. The lower left corner was particularly bad.

Sealed it up with RTV sealant and even had to use clamps on the lower corners of the sprung door, but it handled much better after that. Before, I was getting all kinds of funky readings from temp gauges, both analog and digital. Not after.
 

aggie09

Newbie
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Joined Oct 14, 2021
Thanks for all the replies! I appreciate all the insight. I already have some of the felt gasket material like used on the BGE, so I'll try that first before the RTV sealant. I'll post a more detailed review/update in a few months when I get more cooks done.
 
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