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My father-in-law built an outdoor fireplace. The opening is 3' x 3' and the chimney was 5', but the smoke tends to go out the opening instead of the chimney. I blocked off 3 sides but that didn't do anything, so I removed one of the sides. I added additional chimney height, but smoke still came out the sides.

Here's a picture of it with a fire going. You can't see it, but some of the smoke is going out the chimney, but as you can see, some of the smoke goes around the chimney.

Any ideas on how to make the chimney draft better?

enter image description here

isherwood
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Tom
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1 Answers1

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Chimney effect only works when the system is mostly closed. You have a wide open firebox, so the mild vacuum created by the flue is basically ignored beyond a few inches from it. (See also complaints about kitchen exhaust hoods.) If this arrangement worked as you expected, all backyard fire pits would have pipes suspended over them.

You need the fire to be closer to the flue opening or you need to close in the sides of the firebox so that there's just one or two relatively small intake openings, concentrating flow. Blocking three sides and leaving the front wide open would only work if there's enough heat coming from the fire to induce updraft (and very little breeze). A weak fire won't do the job.

isherwood
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