Smoke spilling out of back of stove!

[KennyK]

I recently installed a gently used Jotul F100 using the rear flue, and the first few times I burned it, I noticed a little bit of smoke coming off the stove, not out of the door, but from what seemed like the back top area of the stove. I thought it might be the stove paint as I had used some on the stove and flue, and/or maybe that the seal where the flue enters the collar of the stove vent wasn't totally sealed. It would only do that as I was starting to burn and after a few times using the stove it stopped happening. Tonight, a few weeks into using the stove, it happened again. Tonight it appeared like the smoke was coming from lower down on the back of the stove, but there's a rear heat shield, so it was hard to tell and I thought it might have been coming from another area of the stove but getting trapped between the stove and heatshield and coming out at the bottom of the shield. It looked to me to be a little more smoke than I had seen before, though not a ton, perhaps about as much as when you put out a candle, and it lasted less than about a minute until the draft got going. Any thoughts? Could this be something dangerous? Before using the stove I removed the top and vacuumed it out, I didn't notice any cracks, and the gasket seemed to be in good shape but perhaps I didn't totally line up the gasket. When the installed the stove, they put some sort of black paste like sealant when the flue enters the flue collar, but some chipped off - I thought this was just excess, but maybe not. Any input on how concerned I should be and/or how I might address this would be greatly appreciated.

Thanks!

 

[Sprinter]

I recently installed a gently used Jotul F100 using the rear flue, and the first few times I burned it, I noticed a little bit of smoke coming off the stove, not out of the door, but from what seemed like the back top area of the stove. I thought it might be the stove paint as I had used some on the stove and flue, and/or maybe that the seal where the flue enters the collar of the stove vent wasn't totally sealed. It would only do that as I was starting to burn and after a few times using the stove it stopped happening. Tonight, a few weeks into using the stove, it happened again. Tonight it appeared like the smoke was coming from lower down on the back of the stove, but there's a rear heat shield, so it was hard to tell and I thought it might have been coming from another area of the stove but getting trapped between the stove and heatshield and coming out at the bottom of the shield. It looked to me to be a little more smoke than I had seen before, though not a ton, perhaps about as much as when you put out a candle, and it lasted less than about a minute until the draft got going. Any thoughts? Could this be something dangerous? Before using the stove I removed the top and vacuumed it out, I didn't notice any cracks, and the gasket seemed to be in good shape but perhaps I didn't totally line up the gasket. When the installed the stove, they put some sort of black paste like sealant when the flue enters the flue collar, but some chipped off - I thought this was just excess, but maybe not. Any input on how concerned I should be and/or how I might address this would be greatly appreciated.

Thanks!

I'm going to put in my 2 cents, then lets others have it. That black paste if it is now hardened sounds something like Rutland cement. That kind of thing, or any sealant, shouldnt be necessary on the flue. The positive pressure after the collar should prevent fire smoke from leaving.

Is the flue installed so it sits on the outside or inside of the collar? Is the smoke from the fire or does it smell chemically? Single wall or double wall flue?

We have some good, experienced installers here that can help better, but this sounds like an installation problem to me, unless it really is just paint curing off

 

[bholler]

I recently installed a gently used Jotul F100 using the rear flue, and the first few times I burned it, I noticed a little bit of smoke coming off the stove, not out of the door, but from what seemed like the back top area of the stove. I thought it might be the stove paint as I had used some on the stove and flue, and/or maybe that the seal where the flue enters the collar of the stove vent wasn't totally sealed. It would only do that as I was starting to burn and after a few times using the stove it stopped happening. Tonight, a few weeks into using the stove, it happened again. Tonight it appeared like the smoke was coming from lower down on the back of the stove, but there's a rear heat shield, so it was hard to tell and I thought it might have been coming from another area of the stove but getting trapped between the stove and heatshield and coming out at the bottom of the shield. It looked to me to be a little more smoke than I had seen before, though not a ton, perhaps about as much as when you put out a candle, and it lasted less than about a minute until the draft got going. Any thoughts? Could this be something dangerous? Before using the stove I removed the top and vacuumed it out, I didn't notice any cracks, and the gasket seemed to be in good shape but perhaps I didn't totally line up the gasket. When the installed the stove, they put some sort of black paste like sealant when the flue enters the flue collar, but some chipped off - I thought this was just excess, but maybe not. Any input on how concerned I should be and/or how I might address this would be greatly appreciated.

Thanks!

What is your chimney setup? It sounds like lack of draft to me.

 

[Woody Stover]

Yeah, probably furnace cement. If part of it cracked out, it could leak a little smoke there if draft wasn't strong with a cold flue. Warm outside temps would exacerbate the sitchiation, especially on a stove that wants strong draft, which I assume that is..

 

[Sprinter]

Yeah, I was about to ask that too. How tall is your chimney from stove to peak? Is there sufficient clearance from the peak of the roof, etc? A lot of things can cause a poor draft.

 

[KennyK]

I'm going to put in my 2 cents, then lets others have it. That black paste if it is now hardened sounds something like Rutland cement. That kind of thing, or any sealant, shouldnt be necessary on the flue. The positive pressure after the collar should prevent fire smoke from leaving.

Is the flue installed so it sits on the outside or inside of the collar? Is the smoke from the fire or does it smell chemically? Single wall or double wall flue?

We have some good, experienced installers here that can help better, but this sounds like an installation problem to me, unless it really is just paint curing off

Flue sits inside collar. The first few days I used the stove I was getting a chemical smell but it went away, smelled like wood today. Single wall flue.

 

[KennyK]

Temps were definitely warmer today when I lit the stove. I'm new to burning, but I haven't seemed to have any draft problems, but maybe that was it. I'd certainly prefer that than anything more dangerous! With my lack of experience, when I read about back draft, I always imagined that pushing smoke out the door of the stove, could it push smoke out other parts of the stove, like where the flue meets the collar or other areas? I have a 30 foot 6 inch insulated smooth walled flex liner inside a masonry chimney to a T to a short piece of single wall stove pipe to the rear exhaust on the stove, and again, in my little time burning, it seems to be working well. The chimney clears the roof by just about the minimum that the manual calls for.

 

[Sprinter]

I have a 30 foot 6 inch insulated smooth walled flex liner inside a masonry chimney to a T to a short piece of single wall stove pipe to the rear exhaust on the stove

Wow, usually, a 30' tall flue would be causing excessive draft if anything, not insufficient draft.

 

[HomeinPA]

When the stove is cold and you open the door to the stove and hold your hand at the top of the door, do you feel cold air? It sounded like it was during startup. Was the fire very lazy and the stove full of smoke when this happened?

 

[KennyK]

When the stove is cold and you open the door to the stove and hold your hand at the top of the door, do you feel cold air? It sounded like it was during startup. Was the fire very lazy and the stove full of smoke when this happened?

This was right at the startup. The stove had a bunch of kindling, some newspaper and a fairly small split or two. It only lasted about a minute and happened about a minute after lighting the newspaper just as the kindling was starting to catch.

As for your first question, I'll have to check later - the stove is currently cruising along at 550 degrees! Do you mean cold air coming in from the flue out towards the direction of the stove door? If so, I don't think so.

 

[HomeinPA]

This was right at the startup. The stove had a bunch of kindling, some newspaper and a fairly small split or two. It only lasted about a minute and happened about a minute after lighting the newspaper just as the kindling was starting to catch.

As for your first question, I'll have to check later - the stove is currently cruising along at 550 degrees! Do you mean cold air coming in from the flue out towards the direction of the stove door? If so, I don't think so.

Yeah. I'm thinkin' up in Boston there, being a bit chilly and all, you might have an issue with pushing that column of cold air out at start up and the smoke you see is just eeking out of any crack it can find. Probably an air inlet under the stove. Next time you try cold starting the stove pop open a window about 6 inches or open the door a bit, go back and light the fire and get it going and then close the window. You should see a good lively flame the entire time. If it get's lazy and dies down it's not drafting right. I have the same issue many times.

 

[RobbieB]

That's why I play the flame of the propane torch back and forth over the top of the stove before I put it to the paper.

Get that column of cold air up the flue before the smoke starts.

 

[firefighterjake]

Yeah. I'm thinkin' up in Boston there, being a bit chilly and all, you might have an issue with pushing that column of cold air out at start up and the smoke you see is just eeking out of any crack it can find. Probably an air inlet under the stove. Next time you try cold starting the stove pop open a window about 6 inches or open the door a bit, go back and light the fire and get it going and then close the window. You should see a good lively flame the entire time. If it get's lazy and dies down it's not drafting right. I have the same issue many times.

+1 . . . warmer temps outside most likely meant not a very strong draft. I have a pretty tall chimney and in the shoulder season often need to open a nearby window a couple of inches to establish a draft.

 

[black smoke signals]

Like bholler said it sounds like draft is your problem check the tee connections = Draft killers

 

[black smoke signals]

If it get's lazy and dies down it's not drafting right. I have the same issue many times.

So can you install an oak on your stove to help eliminate your issues?

 

[HomeinPA]

So can you install an oak on your stove to help eliminate your issues?

Maybe. It depends. In my case it's a house pressurization issue which I don't think a little 3" OAK is going to solve but then again, I've not worried about it that much. It's easier for me to pop the basement door open for a couple minutes than to let cold air into my house on a constant basis.

 

[JabaduGarfunkle]

That happens to me every time i start the stove from cold. I've always assumed that the smoky air caused by burning newspaper and kindling are coming out the air inlet during startup and it always goes away as soon as I get anything even remotely going. It's usually not much time begin with.

I'll have to check for cracks or something now in case there's not supposed to be an 'air inlet' there since I do have trouble keeping the temp below 700 when the winds are strong and giving me too much draft. Maybe that smoke is showing me where too much air gets in?

 

[KennyK]

Thanks everyone! I'm feeling much better, as it seems like this isn't abnormal or a dangerous situation where fire is going to jump out of my stove, rather just that some smoke is sneaking out when there isn't a great draft (which so far hasn't been often nor for more than a minute start up from cold stove). Seems like maybe I should go put a little more stove cement around where the flue goes into the collar, as well as perhaps at the T and where the T connect with the liner - seem right?

 

[begreen]

Is this fireplace in the basement? It sounds like you will need to get the draft moving up the flue before starting a fire. Some tricks are using a source of heat above the baffle if possible. Some use a propane torch or a heat gun. It might take a while due to the horiz. run out the back of the stove and then the 90º turn at the tee. Once draft is established you might try a top down start to minimize smoke while the flue is warming up.

 

[Sprinter]

Seems like maybe I should go put a little more stove cement around where the flue goes into the collar, as well as perhaps at the T and where the T connect with the liner - seem right?

Sealing up flue joints shouldn't be necessary, but probably won't hurt either I suppose. Better to fix the actual problem IMO. If smoke is escaping through the flue like that, you still have a problem to solve first.

 

[KennyK]

Is this fireplace in the basement? It sounds like you will need to get the draft moving up the flue before starting a fire. Some tricks are using a source of heat above the baffle if possible. Some use a propane torch or a heat gun. It might take a while due to the horiz. run out the back of the stove and then the 90º turn at the tee. Once draft is established you might try a top down start to minimize smoke while the flue is warming up.

The fireplace is not in the basement - first floor of a three story house. Again, most of the times I've run the stove this happened, and when it did, it was only for a few seconds and then draft seems to get going strong, so I'm not overly worried now that I know it's not an abnormal thing. That said, I will keep my eye on it and try some the flue warming tricks mentioned here. I don't have a very long horizontal run to the T (I'd say 8 to 12 inches), however, I'm considering swapping out a different stove and perhaps putting in a longer horizontal run - is a longer horizontal run a bad idea? How long of horizontal from a rear exit stove to a 90 T is too long?

 

[KennyK]

Sealing up flue joints shouldn't be necessary, but probably won't hurt either I suppose. Better to fix the actual problem IMO.

In regards to fixing the actually problem, what do you think that might be? You suggested in an earlier post that it sounded like an installation problem. Since, a bunch of folks (including you!) have said it sounds like draft. Do you think that there could be an installation or other problem, and if so, what should I look for?

 

[begreen]

The fireplace is not in the basement - first floor of a three story house. Again, most of the times I've run the stove this happened, and when it did, it was only for a few seconds and then draft seems to get going strong, so I'm not overly worried now that I know it's not an abnormal thing. That said, I will keep my eye on it and try some the flue warming tricks mentioned here. I don't have a very long horizontal run to the T (I'd say 8 to 12 inches), however, I'm considering swapping out a different stove and perhaps putting in a longer horizontal run - is a longer horizontal run a bad idea? How long of horizontal from a rear exit stove to a 90 T is too long?

8" to 12" isn't too bad. 24-36" would be worse.

Most houses with a 1st floor 30' flue would be complaining of too strong draft. Is there a vent, leaky windows or doors on the third floor?

 

[Sprinter]

In regards to fixing the actually problem, what do you think that might be? You suggested in an earlier post that it sounded like an installation problem. Since a bunch of folks (including you!) have said it sounds like draft. Do you think that there could be an installation or other problem, and if so, what should I look for?

Sorry for any confusion. So far it does sound like a draft problem. My comment was only meant to say that whatever is causing this and whatever the solution is, sealing the flue up shouldn't be necessary IMO. It's hard to diagnose problems and suggest solutions without being there. "Installation problems" can mean anything. Not necessarily a poor installation job.

 

[KennyK]

Sorry for any confusion. So far it does sound like a draft problem. My comment was only meant to say that whatever is causing this and whatever the solution is, sealing the flue up shouldn't be necessary IMO. It's hard to diagnose problems and suggest solutions without being there. "Installation problems" can mean anything. Not necessarily a poor installation job.

Thanks for the clarification! I will keep at it!