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Discussion Starter · #1 ·
I have an old fireplace that has never worked well, and always smokes up the room and house when used (even with all air conditioning and bathroom/kitchen vents off).

I believe part of the problem is inadequate venting due to the negative pressure in the house. I see some items in the marketplace that can be installed for external, fresh combustion air, and is supposed to help with the smoke and negative pressure issues.

Anyone have experience with this ?

Does it work, or no ?
 

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retired framer
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If you have an outside ash clean out with a hole in the back of the fire box. sometimes just opening that door will give you enough fire air.

Are you warming the chimney or starting the draft when you light the fire?
 

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Couple of potential issues including the one that you are thinking, e.g. deficiencies in the formula governing opening width bye height by depth....as well as potential placement of smoke shelf.
 

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Do you know how to use a fireplace? That's not an insult. We just don't know.

Did you check the obvious stuff? Is there a blockage? Is the damper functioning properly? Sometimes the damper linkage breaks and even though you think it's open, it actually isn't.

If it's an "old fireplace", can we assume it's an old house? If it's an old house, it's probably not sealed up that well. I don't know if the negative pressure is an issue. You could try it with the front door wide open. Then you definitely don't have much negative pressure. How much smoke is coming out the top of the chimney? Seems like an easy thing to diagnose.

Maybe it is the wood you are burning or something unrelated to the air flow.
 

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It doesn't really get cold enough here in SA to make a fire place worth it as it usually only freezes just 2-4 days a year here and barely below 32 at that.
 

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Hi Bootz and welcome to the forum. Last question first, "Anyone have experience with this ?" Lots of experience but I'll wait for your return before starting.

Bud
 

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Discussion Starter · #8 ·
When I say old, I mean a 70's home build. Cheaply made it seems. not brick or anything like that. looks like a cheap insert thing.

When I get the time, I'll check the damper function and flue. I just recently got it cleaned out well enough to even look in it.

BTW, don't really know JACK about fireplaces, and this one has rarely been used due to the smokey situation we've experienced since I was a kid.

Just looking for information before I get in and get really dirty, and be ready for a best/worse case scenario. I may even remove it and do something else with the space, but a working fireplace might be nice as well.
 

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Thanks for returning, it is a good topic to go over as there are many "good old fireplaces" that suffer the smoky problem.

The truth is, many were never built to work do to a lack of understanding why.

Some questions:
1. Describe your house, ranch, 2-story, basement, and where is the fireplace located?
2. Does the fireplace chimney pass up through the conditioned living space, or is it on an outside wall exposed to the cold.
3. Is the chimney/flue used for only that fireplace?
4. An outside picture might help, but does the chimney extend well above the roof?
In that pictures if you can show the surrounding homes and trees.
5. A picture of the front of the fireplace also?

It was mentioned that opening the front door would eliminate any negative pressure, that is not correct. When it is cold outside a home will still experience a stack effect with a positive pressure up high and a negative pressure down low. But we need answers to the above before we blame house pressures.

Bud
 

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It was mentioned that opening the front door would eliminate any negative pressure, that is not correct. When it is cold outside a home will still experience a stack effect with a positive pressure up high and a negative pressure down low.
I'm not following that. This is my train of thought. Hot air rises. If you are leaking hot air into the attic, that has to get replaced by cool air coming in. If there is a lot of air leaking out and no place for it to come in downstairs, that negative pressure can suck air DOWN the chimney. That's not good.

But if the front door is wide open, there will be plenty of air coming in to replace the air leaking into the attic. This problem goes away, no?
 

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I'm not following that. This is my train of thought. Hot air rises. If you are leaking hot air into the attic, that has to get replaced by cool air coming in. If there is a lot of air leaking out and no place for it to come in downstairs, that negative pressure can suck air DOWN the chimney. That's not good.

But if the front door is wide open, there will be plenty of air coming in to replace the air leaking into the attic. This problem goes away, no?
Hi mm, don't feel like you are alone, the explanation runs contrary to long term thinking and requires a lot of support information to change that thinking. For your question here I will try to be short.
The volume of incoming air MUST always equal the volume of outgoing air. The stack effect I mentioned will adjust high and low pressures to keep those two equal. So opening a front door (or a window) that allows more air to come in will be balanced by a shift in pressures that forces more air out which is why opening a window can sometimes help to force more air up and out a chimney, better draft. Note I said sometimes because there are other factors like a basement window would help more than a second floor window.

The open a window suggestion should only be used as a test, it is not a solution as very easy for someone to close that window and cause a potential problem as the fire finally dies out.

An outside chimney and even some inside chimneys can end up filled with cold (heavy) air. Add in some wind and bad air currents and that nice fireplace gets the nickname "old smoky"

When Bootz gets back with more details we will see if his can be made to work.

Bud
 

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retired framer
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Have you checked the top outside for a birds nest, if you can't see down from the top, tie a weight to a rope and drop it in there and mark the rope when it stops so you can measure that it makes it all the way to the bottom.
 

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Having experienced back-drafting chimneys with a wood stove, one thing it has surly taught me is to always check the draft condition before I light it. In my case cracking a near by window has always solved the issue.

But I check for draft using a stick candle. If the draft is not there the fire doesn't get lit.

Another quick comment. At least in my situation, the colder the outside air, the better my chimney drafts. But as outside temps warm, the the draft weakens.

But in any condition, once I get the chimney warmed up it works well.
 

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retired framer
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The goal is to use the fireplace without opening windows/doors, etc.
That's why I was asking about the external vent.

I'll be getting on the roof eventually and checking for blockage, and possibly cleaning if needed. I don't believe it's ever been cleaned.

Curious about items like this : The Drescher Air Vent

https://www.weixindustries.com/the-drescher-fireplace-vent/

people are suggesting open doors and windows and fire starting procedures to find out if that is the problem before agreeing that you should spend the time and money on something that would not help.
 

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Discussion Starter · #18 ·
I see.. OK, I'll have to check that out at a later date, it makes sense. Not in a position to spend much time on it. Good ideas for later, though

Thanx everyone who responded
 
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