Wood stove and fireplace sharing same flue

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snosurfa7

Member
Mar 25, 2009
48
VA
Looked at a property this past week, built in 1977. Had a large stone fireplace on one side but on the back had a wood stove with a pipe going into the back of the same large stone fireplace. To get an idea this was one of those tall, all stone all the way around fireplaces - so it is not like the pipe was going into drywall or anything, just directly into the back of the fireplace/chimney.

Looked like the wood stove chimney pipe just emptied out into the chimney for the fireplace. The pipe did empty into above the flue as well, not near where the fire would be burning.

Now I now technically you should have your chimney lined and stove pipe going all the way up, but, provided this chimney is built to spec, is this still a sketchy set-up? And if so, why?
 
If, in fact, the chimney structure has but a single flue up to daylight and the woodstove is just piped into the same flue as the open fireplace, then it's not just "sketchy", it's illegal and unsafe. The reason being that with either appliance burning and the other not, should anything untoward happen with the drafting up the flue, the exhaust gases from the operating appliance can enter the living space through the other appliance. You might be burning in the wood stove and have toxic gases coming into the house through the open fireplace. Not good. Rick
 
You might have misunderstood the set-up...if you are burning the stove, you can close the flue - nothing can get into the fireplace section. The stove pipe empties above the flue for the fireplace.

If you are burning the fireplace - well, I guess some gases could get into the wood stove but the wood stove is technically a closed unit. And I'm assuming most gases would prefer to travel up the chimney and not into the stove pipe at an angle then down back into the wood stove.

I agree though, it seems unsafe at first glance but when you think about it I'm not quite sure how dangerous it really is. But the thing is, I'd like to fix it to make it consistent with current guidelines in the sense of my current wood stove set-up - and I'm not quite sure how to do that. You can't really run a pipe all the way up the chimney because if you burn in the fireplace cresote would build up on the outside of that pipe too...and that can't be safe.
 
snosurfa7 said:
You might have misunderstood the set-up...

I think I understood it just fine.

snosurfa7 said:
...if you are burning the stove, you can close the flue - nothing can get into the fireplace section. The stove pipe empties above the flue for the fireplace...

Terminology problem here. It's important that we all sing from the same sheet of music. The "flue" in any application originates at the appliance and terminates when it gets up and out to daylight. I think what you're calling the "flue" is really the damper for the fireplace. These are not gas-tight fixtures.

snosurfa7 said:
...If you are burning the fireplace - well, I guess some gases could get into the wood stove but the wood stove is technically a closed unit. And I'm assuming most gases would prefer to travel up the chimney and not into the stove pipe at an angle then down back into the wood stove...

No, the woodstove is not a "closed unit". Gases will go wherever they can find a path to go. If down and out into your living space is easier than up and out to daylight, then into the living space they'll go. All it takes is a pressure differential, and that can be the result of any number of things.

snosurfa7 said:
...I agree though, it seems unsafe at first glance but when you think about it I'm not quite sure how dangerous it really is...

I am thinking about it. I wouldn't have that set up in my house.

snosurfa7 said:
...But the thing is, I'd like to fix it to make it consistent with current guidelines in the sense of my current wood stove set-up - and I'm not quite sure how to do that. You can't really run a pipe all the way up the chimney because if you burn in the fireplace cresote would build up on the outside of that pipe too...and that can't be safe.

If you don't want to install a separate flue for the woodstove, then you need to make a choice between the two appliances. If it's the woodstove you want to use, then install a liner the full height of the chimney and permanently disable the open fireplace. If it's the fireplace you want to use, then rip out the woodstove and patch the chimney structure penetration. Rick
 
fossil said:
snosurfa7 said:
You might have misunderstood the set-up...

I think I understood it just fine.

snosurfa7 said:
...if you are burning the stove, you can close the flue - nothing can get into the fireplace section. The stove pipe empties above the flue for the fireplace...

Terminology problem here. It's important that we all sing from the same sheet of music. The "flue" in any application originates at the appliance and terminates when it gets up and out to daylight. I think what you're calling the "flue" is really the damper for the fireplace. These are not gas-tight fixtures.

snosurfa7 said:
...If you are burning the fireplace - well, I guess some gases could get into the wood stove but the wood stove is technically a closed unit. And I'm assuming most gases would prefer to travel up the chimney and not into the stove pipe at an angle then down back into the wood stove...

No, the woodstove is not a "closed unit". Gases will go wherever they can find a path to go. If down and out into your living space is easier than up and out to daylight, then into the living space they'll go. All it takes is a pressure differential, and that can be the result of any number of things.

snosurfa7 said:
...I agree though, it seems unsafe at first glance but when you think about it I'm not quite sure how dangerous it really is...

I am thinking about it. I wouldn't have that set up in my house.

snosurfa7 said:
...But the thing is, I'd like to fix it to make it consistent with current guidelines in the sense of my current wood stove set-up - and I'm not quite sure how to do that. You can't really run a pipe all the way up the chimney because if you burn in the fireplace cresote would build up on the outside of that pipe too...and that can't be safe.

If you don't want to install a separate flue for the woodstove, then you need to make a choice between the two appliances. If it's the woodstove you want to use, then install a liner the full height of the chimney and permanently disable the open fireplace. If it's the fireplace you want to use, then rip out the woodstove and patch the chimney structure penetration. Rick

Very Well said Rick...... Only one appliance per chimney. No Matter what it is. It could be a Pellet stove, Gas Hot Water Heater, Etc.
 
Well said, point taken. You are right - damper not flue.

Well, I figured if the current set-up was inappropriate (which it sounds like it is) I'd just put an insert in the fireplace and take out the old woodstove. But it is one of those fireplaces that you just want to burn a big old fire in, so I might have to, if I get the property, just put a woodstove elsewhere - it's just a pretty small place and not much room elsewhere but I'm sure I could find a place. Maybe an external wood burner - anything so as to not have to fill up the current oil furnace.

Thanks
 
Consider installing a decent sized, EPA insert with a nice fire view. A modern EPA stove will keep the glass clean as long as you are burning dry wood properly. Maybe a Buck 74 will fit? Try that for a year. It could be that the masonry heats up enough from the insert that an additional stove would be superfluous.
 
snosurfa7, Rick gave you some really good answers. Then besides his answers one might consider what might happen should the worse happen. Would you insurance pay in case of a fire when they found an illegal situation? For sure it would not meet code so therefore they probably could get out of paying.

I've found it best to exceed code if at all possible. Some just go by code but there is nothing to stop someone from going past what code requires.
 
Backwoods Savage said:
I've found it best to exceed code if at all possible. Some just go by code but there is nothing to stop someone from going past what code requires.

You got it Dennis, code is by far just the minimum and still to me questionable at times. When the poop hits the fan, it is nice to know you covered all the bases. Its not a case IF, but WHEN that most things can happen. My home and family are not up to experiments. :coolsmile:
 
Did you take a look at the chimney outside to see if there is 1 or 2 chimney flues? A big stone structure like you discribe might have 2 seperate flues inside.
 
Todd said:
Did you take a look at the chimney outside to see if there is 1 or 2 chimney flues? A big stone structure like you discribe might have 2 seperate flues inside.

+1 My thoughts exactly. Brilliant minds think alike - you wouldn't happen to have a Keystone woodstove too? ;)

Bill
 
north of 60 said:
Backwoods Savage said:
I've found it best to exceed code if at all possible. Some just go by code but there is nothing to stop someone from going past what code requires.

You got it Dennis, code is by far just the minimum and still to me questionable at times. When the poop hits the fan, it is nice to know you covered all the bases. Its not a case IF, but WHEN that most things can happen. My home and family are not up to experiments. :coolsmile:


Right North. Hey, I guess the heating season is upon you up there huh? Hope you were able to get more wood over the summer. How is the tourism doing now? Do you notice a decrease in traffic? Then there is hunting season and I well remember some of the big moose we saw up there. Would love to hunt there sometime.
 
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