# Does length really matter



## SCtrailrider (May 1, 2016)

I have a 20' container I use as a clean room to build motors.

I installed a small wood burning stove for some heat, my Dad had this one but wasn't using it and it's small enough it doesn't take up much room.

https://jotul.com/us/products/wood-stoves/j%C3%B8tul-f-400-cf-castine

My flue pipe is 6" and is 8' tall, the stove doesn't really draw good, I know this type of stove isn't like the one in my home but I think it should draw better, I half to crack open the bottom ash door and then it draws good.

The instructions say the pipe should be at least 15' long but that will be a lot sticking out above the container and I doubt I could figure out how to support it so it doesn't get blown over.

As it is at 8' long it's 2' above the top of the container.

So, the question is does the flue pipe really need to be longer?

I'll post a pic later today..

Thanks, Chris


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## Tx Jim (Jun 30, 2014)

8' seems awful short for chimney. I'd guess 15' chimney is mentioned in instructions for a very good reason.


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## slowzuki (Mar 8, 2011)

Tall insulated chimney will always draw better. If it doesn't draft the min pressure designed into the stove you will have to have a bigger air opening as you have found out.

Lower pressure = bigger hole needed to move same amount of air through

In case of an air-tight stove the draft controls are the choke point hole.


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## SCtrailrider (May 1, 2016)

Well i added 5' more to the length, I can sort of tell a difference it does stick way high above the container, I can see I'm going to need to figure out how to stabilize it from the wind..


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## Palmettokat (Jul 10, 2017)

Chris, I have seen flu supported by three wires run of course three different directions to support the flu. You may need two different heights supported.

My father in law built a shop with a wood burning stove (the old kitchen wooden stove, not the air tight type) it draws very well but far from air tight but that flu is not over 12 feet.


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## farmersamm (Nov 2, 2017)

Weld a 'mast' onto your container, and tie off to the chimney with some sort of something strong enough to take the stress. Probably some used pipe ought to be strong enough for the mast, just weld it to the thick corners of the box.


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## rjmoses (Apr 4, 2010)

Another thought: I'm guessing you're talking about a steel shipping container? If so, it may be too air tight to allow enough air in to meet the needed pressure differential. You might have to add an inlet vent to the container.

Ralph


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