Kuuma vapor fire smoke question.

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

Micdrew

Member
Jan 15, 2021
53
Maryland
Hello again, another question about my new vaporfire, so I’ve been burning nights mostly due to warm temps as I had mentioned in my last post but today it’s about 41 with a lot of moisture in the air so I’ve kept it running I’ve been working outside and I noticed a light gray smoke coming from the chimney (class A 6”), I’m about an hour into a small load of maple with the computer on little c when I take a light and shine it into the smoke pipe via the damper I don’t see any smoke so am I seeing water vapor out the chimney? I thought there should be no smoke and water vapor when temps are below 32 but like I said it’s about 41 anyone else run into this?
 

Highbeam

Minister of Fire
Dec 28, 2006
19,698
Mt. Rainier Foothills, WA
Visible steam can occur at well above freezing ambient temperatures. Think of your foggy breath, steamy car exhaust, or actual fog in San Francisco.
 

brenndatomu

Minister of Fire
Aug 21, 2013
7,130
NE Ohio
Heck I've seen vapor like that in the 50's sometimes...no biggie. Remember, there is always still some moisture in the wood, even dry wood....if you loaded 50lbs of wood and its 15% MC then that's 7.5lbs water...almost a gallon!
 

salecker

Minister of Fire
Aug 22, 2010
1,795
Northern Canada
Gotta love Hearth for helping a person learn
 

JRHAWK9

Minister of Fire
Jan 8, 2014
1,857
Wisconsin Dells, WI
Water vapor will generally be lighter and will disappear as it moves away from the chimney. Smoke will linger and may even tend to drop as it moves away from the chimney.

Old photos, but this is all water vapor. I believe it was quite cold that day as well.

2015-02-22 16.05.36.jpg 2015-02-22 16.05.55.jpg
 

Micdrew

Member
Jan 15, 2021
53
Maryland
That’s what I had coming out of my chimney this morning with temps in low 20s, I believe I figured out what was happening on Saturday, what I was seeing was smoke, being that it was 74 in the house I was burning a smaller load and had loaded on a small amount of coals, the firebox must not of been hot enough to get a complete burn of all the gasses even with the computer on pilot so yesterday around 1 pm I loaded 10 splits on a nice bed of coals the computer went to pilot within 5-10min I walked out and checked and had 0 smoke coming from chimney. I’ll just have to play around with my loads during the more mild temps and maybe crack some windows if it gets to warm.
 

brenndatomu

Minister of Fire
Aug 21, 2013
7,130
NE Ohio
the firebox must not of been hot enough to get a complete burn of all the gasses even with the computer on pilot
If the computer had closed the intake (c) then the firebox was hot enough to allow this...keep in mind, the computer is always monitoring firebox temps...now if the computer said (3) and it was smoking, then I would say its possible that the fire was too small, crappy wood, etc to have a hot clean fire...
 

JRHAWK9

Minister of Fire
Jan 8, 2014
1,857
Wisconsin Dells, WI
There is no reason to overload for your heat load. You may have had a piece of wet wood or something coupled with a low draft situation.

Or you could have been on pilot 'c' with your firebox temps dropping and right before it opened up to '1'. This could have caused a smoky situation if firebox temps were not hot enough. Either way, it should have been a temporary issue and not something to worry about.

I do small loads all the time and while it definitely is not the most efficient way, I wouldn't overheat the house/waste wood because of it.
 
  • Like
Reactions: Micdrew

brenndatomu

Minister of Fire
Aug 21, 2013
7,130
NE Ohio
I still think it was steam...
on little c when I take a light and shine it into the smoke pipe via the damper I don’t see any smoke
...if for no other reason than this statement ^ ^ ^
 

JRHAWK9

Minister of Fire
Jan 8, 2014
1,857
Wisconsin Dells, WI
I still think it was steam...

...if for no other reason than this statement ^ ^ ^

good point. Shining a light into there will definitely tell you if it's smoke...as the light will illuminate any smoke.
 

Micdrew

Member
Jan 15, 2021
53
Maryland
I’ll keep messing with it, seems like it’s gunna have to get a lot colder for it not to over heat the house I like 72 myself but I just called my wife and she said it’s 75 it’s currently 34 here now, I’ve got my draft set at 4 should I take down lower?
 

JRHAWK9

Minister of Fire
Jan 8, 2014
1,857
Wisconsin Dells, WI
You will figure out how much wood to load for your heat load. I do varying sized loads depending on how cold it is outside. I routinely do smaller 20-30 lb loads to keep the house around 72°.

Even this non-efficient house I can not keep a fire going when outside temps are a warm 34°.
 

brenndatomu

Minister of Fire
Aug 21, 2013
7,130
NE Ohio
I’ll keep messing with it, seems like it’s gunna have to get a lot colder for it not to over heat the house I like 72 myself but I just called my wife and she said it’s 75 it’s currently 34 here now, I’ve got my draft set at 4 should I take down lower?
Sounds like you are in a similar situation to me...spend a good portion of the winter heating with sorta mild outdoor temps.
We have had temps in the upper 20s/low 30s at night and in the 40s during the day here of late...so far this year I have mostly been burning (2) 25-30lb loads of Box Elder per day to keep the house in the 70-72* range...but I'm also turning the computer off after 3-4 hours though too...seems to help even things out some, and helps there to be some hot coals left when loading twice/day.
 

brenndatomu

Minister of Fire
Aug 21, 2013
7,130
NE Ohio
Even this non-efficient house I can not keep a fire going when outside temps are a warm 34°.
You get some decent solar gains on sunny days though too, correct?
Our place benefits very little from solar gain...
 

JRHAWK9

Minister of Fire
Jan 8, 2014
1,857
Wisconsin Dells, WI
You get some decent solar gains on sunny days though too, correct?
Our place benefits very little from solar gain...

yes we do. Even so, that's still too warm to be able to keep a fire going now. The first couple years of burning, before tweaking my blower speed and return air, I could keep a fire going in those temps, but not anymore. Those are working outside in a t-shirt temps! ;lol
 

Micdrew

Member
Jan 15, 2021
53
Maryland
Great tips thanks guys, I went ahead and called Dale and he said I could go ahead a take the heat baffles out until it gets colder he said that will drop the heat output by roughly 20%....
 

JRHAWK9

Minister of Fire
Jan 8, 2014
1,857
Wisconsin Dells, WI
Great tips thanks guys, I went ahead and called Dale and he said I could go ahead a take the heat baffles out until it gets colder he said that will drop the heat output by roughly 20%....

yeah, you'll just be sending that heat up the chimney instead. Personally, I'd rather just load accordingly. Just do a small loads here and there when needed.

I did a small load last night. House was 68° when we got up and the fire was out....it was 24° outside. I then was able to uncover some coals this morning and loaded 30lbs and that brought the house up to 74° or so. It got up to 36° today outside. Blower just shut off about 30 minutes ago. It's 25° outside and 72° in the house. I won't be doing another fire until bedtime.

OK, I just looked at the forecast, supposed to get down to 12° tonight. So I'll probably be lighting a fire a couple hours or so before bed, so I can do the night load on some coals........depending on how the house temp is.
 

Micdrew

Member
Jan 15, 2021
53
Maryland
yeah, you'll just be sending that heat up the chimney instead. Personally, I'd rather just load accordingly. Just do a small loads here and there when needed.

I did a small load last night. House was 68° when we got up and the fire was out....it was 24° outside. I then was able to uncover some coals this morning and loaded 30lbs and that brought the house up to 74° or so. It got up to 36° today outside. Blower just shut off about 30 minutes ago. It's 25° outside and 72° in the house. I won't be doing another fire until bedtime.

OK, I just looked at the forecast, supposed to get down to 12° tonight. So I'll probably be lighting a fire a couple hours or so before bed, so I can do the night load on some coals........depending on how the house temp is.
Yeah I agree I don’t like sending the heat up the chimney, I’ll have to get a scale so I can start weighing my wood and will start having my wife turn the computer off once the computer goes to 3 so I can keep some coals for the next load.
 

JRHAWK9

Minister of Fire
Jan 8, 2014
1,857
Wisconsin Dells, WI
Yeah I agree I don’t like sending the heat up the chimney, I’ll have to get a scale so I can start weighing my wood and will start having my wife turn the computer off once the computer goes to 3 so I can keep some coals for the next load.

You'll get a handle over time on how much to load for your heat load and outside temps. Just takes time. :)

I too sometimes turn it off. I actually have a remote switch wired so I can turn it off from upstairs. Problem is, when I do that, about 75% of the time I forget to turn it back on when I go down to light a fire. So I end up having to run back upstairs to turn it back on. So I tend to not turn it off remotely as much as I could.
 
  • Like
Reactions: Micdrew

brenndatomu

Minister of Fire
Aug 21, 2013
7,130
NE Ohio
I actually have a remote switch wired so I can turn it off from upstairs. Problem is, when I do that, about 75% of the time I forget to turn it back on when I go down to light a fire. So I end up having to run back upstairs to turn it back on.
3 way switches buddy! ;)