Smelly (but clear) "smoke"..am I doing something wrong?

[NothingLikeWood]

I am wondering why the chimney is creating smelly non-visible smoke. This situation happens when the pressure is dropping and the wind is blowing at the angle to feed the mechanical air exchanger for our house. The surprising thing is that it is not visible at the the cap. When I check the firebox it is always on the downside of a fire and the firebox is full of red coals at this point, with a small yellow flame showing up from time to time. To solve the smell, I usually reload, pull out the air (and bring up to cruising) to get rid of the smell. I thought these new stoves were supposed to burn up all smoke and that the coals were just the clean leftovers....maybe I'm mistaken.

We have an air exchanger and if the wind blows just right, the smell of smoke may come into the house (all CO2 detectors read 0). We know that there are ways to handle this from the exchanger side ( especially since it sometime happens due to our neighbors chimney) but I'm wondering if we're burning right. My question is: I'm wondering if the smell is because we have dampered the fire down too much. Should coals have any visible flames at all on the downside of a burn or should be be aiming for some wispy flames. Any thoughts are appreciated. Everything I've learned about burning these new fangled stoves (in my adult life) has been found on this website. Thanks!

 

[Valhalla]

Welcome!

What kind of stove do you have? Maybe add it to your
signature.

Regardless, any wood that is burned will produce
some odor, at least. The amount of visible smoke is dependent
on the device, how it is operated and the fuel. Those
three subjects are discussed in great detail here.

Burn safely and wisely.

 

[Pagey]

I can have a clean burn going with zero visible smoke, walk outside, and still tell you that I am burning wood (especially when I'm burning pine). I don't think any stove can completely eliminate the smells associated with burning wood.

 

[realstihl]

My EPA stove makes a foul odor outside too. It's kind of hard to decribe the smell. Probably depends also on what kind you're burning.

 

[albertj03]

My stove gives off a strange smell sometimes too and when I smell it there is never any smoke coming out of the chimney. It's almost like a hot metal/burning trash combination smell or something but the stove is always burning perfectly normal when I check it. I would like to know if there is anything I can do to get rid of the smell.

 

[Battenkiller]

After the wood is all gasified, the small amount of particulate matter in the flue gases basically disappears. The cool smelling aromatic smoke from something like cherry is gone and you will start to smell the creosote burning off from inside the stove walls and the flue pipe. It's quite noticeable on my non-EPA stove since I make more creosote than most folks probably do, but it is always forming early in the burn and getting burned off later on if you're running your stove hot enough. That's why your stove has that nice clean white look inside after that intense coal bed has been sitting in there for an hour or so.

If I'm working outside and the wind is right, I can even smell the difference between if the stove is burning in updraft mode or in horizontal mode with the bypass closed. In updraft, the smell is just like a campfire, even though you can't see a thing but heat waves coming out the chimney.

 

[woodgeek]

I think you are putting the air down either too far, or too fast. Those coals are still emitting wood gas that you could be burning, as made clear by the periodic flames popping up from time to time. Think of it a continuous jet of flammable gas, but the flame on it doesn't have enough oxygen to stay lit. You are presumably venting a lot more than CO2 and H2O in that operating state, lots of wood gas hydrocarbons and PAHs and maybe CO that if they came out of your car would be considered major pollutants. Moreover, you are wasting fuel and BTUs by running like that, below optimal air.

Try running with a little more air, and look for small flames that burn consistently at the same stage of the combustion cycle/degree of coaling. Your venting will not smell anymore--those flames will burn it up.

 

[Backwoods Savage]

Welcome to the forum NothingLikeWood.


If you burn wood you will get some smell.

When the stove is down to just coals you should open the draft full. This will help burn those coals down. Load the stove before the coals are all gone though as a light coal bed is very helpful.

 

[Highbeam]

Mine smells too. Almost like car exhaust from an early 90s fuel injected gas engine with a catalytic converter. It does not smell like a campfire. Did you expect the flue gasses to be odorless?

 

[firefighterjake]

I suspect you'll get some odor from most heating equipment . . . and wood is no exception. Seeing no visible smoke is a fairly good indication of clean burning, but you may or may not get an odor depending on the wind, atmospheric pressures, etc. The "bad" smell could be related to the particular species of wood that is burning and/or creosote . . . for example I was burning some spruce yesterday which definitely has a different smell (a good smell in my opinion) compared to the ash and maple which is what I mostly burn.