Creosote on chimney flue?

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Btenkhoff

New Member
Jan 2, 2024
20
SE Missouri
I went outside and i noticed this on the outside of my chimney flue. I have been burning non stop for a couple weeks and a total of 3-4 weeks total with the difference being more sporadic based on temps. The first 1.5 ranks i went thru were seasoned hardwood for about 15 months min to 24+ month as it was a mixed pile. The most recent rank i have noticed this on as far the black goo on outside. It was less seasoned and more of a 3-4 months blocked and 3-4 months split and it was a maple i believe. That being said my moisture meter didnt register anything other than low moisture. Is this something to be concerned with or is it a case of looks worse than it is? I figure i have another 1.5 months of burning. About once a week i sprinkle the creosote destroyer powder into the firebox . Can/should that be cleaned off the flue? Also just for reference the crown i did a coating on and dyed it black so don't be concerned by the black crown part. That being said it does appear to be coming down the side of the brick. Any help is appreciated.

[Hearth.com] Creosote on chimney flue? [Hearth.com] Creosote on chimney flue? [Hearth.com] Creosote on chimney flue?
 
20% should be your max, if possible...25 will not burn the best, and leave a mess behind, unless burned VERY hot.
What are you burning in?
 
20% should be your max, if possible...25 will not burn the best, and leave a mess behind, unless burned VERY hot.
What are you burning in?
To clarify the wood i am burning now reads 10% per pictures. I was responding back to someone who asked me what fresh split wood was measuring. That is what was reading 20-25%

I have a wood burning furnace Gemini Model 5000
 
First yes that black mess should be cleaned up
your chimney needs cleaning. fire hazard!
Measure moisture content on a fresh split (face)
anything under 20% is good to go anything over is
hard to burn and get heat also is the cause of
Creosote (water vapour mixed with smoke)
The moisture content of the end grain will be lower
than the same piece resplit and a reading was taken
on the face of the fresh split ( in most cases)
 
First yes that black mess should be cleaned up
your chimney needs cleaning. fire hazard!
Measure moisture content on a fresh split (face)
anything under 20% is good to go anything over is
hard to burn and get heat also is the cause of
Creosote (water vapour mixed with smoke)
The moisture content of the end grain will be lower
than the same piece resplit and a reading was taken
on the face of the fresh split ( in most cases)
Thank you. I guess i am baffled about it because my moisture gauge is reading 11-12% or lower on the stuff i have been burning. Granted like you said that's not taking a piece of that wood and splitting it in half and measuring right then but just on the end and face. Also i had my chimney cleaned in october. Is it fair to say that's not normal to have that much build up in such little time or are you all who are burning 24/7 cleaning it a couple times a year?
 
The amount of creosote is not normal!
All my wood is under 20% and most is at 12 to 14%
I clean my chimney in the fall (checking for birds or
other things that find their way into it)
Then it is cleaned again in January (just did a full
furnace and chimney clean up yesterday)
Then in the spring, it gets a cleaning for the summer
I also check it weekly to see if there is a problem
After all wood heat is my home's main heat source and kept
in prim condition
 
The amount of creosote is not normal!
All my wood is under 20% and most is at 12 to 14%
I clean my chimney in the fall (checking for birds or
other things that find their way into it)
Then it is cleaned again in January (just did a full
furnace and chimney clean up yesterday)
Then in the spring, it gets a cleaning for the summer
I also check it weekly to see if there is a problem
After all wood heat is my home's main heat source and kept
in prim condition
Thank you, i figured it is not normal. I am wondering if my moisture meter is not working properly or something. I am use to doing 1 cleaning a year but i have not been burning wood as a primary heat source so i know that changes the game. Are you cleaning from the inside out or from the roof?
 
Thank you. I guess i am baffled about it because my moisture gauge is reading 11-12% or lower on the stuff i have been burning. Granted like you said that's not taking a piece of that wood and splitting it in half and measuring right then but just on the end and face. Also i had my chimney cleaned in october. Is it fair to say that's not normal to have that much build up in such little time or are you all who are burning 24/7 cleaning it a couple times a year?
You have measure moisture % on a fresh split face not on the end grain. The creosote on your chimney is coming from wet wood, that's the only thing it can be. I have two moisture meters myself ( one came with my OWB ) and they pretty much read the same % on the same piece of wood. I doubt it's your moisture meter.
 
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Are you cleaning from the inside out or from the roof?
At 74 I clean from the inside
For years from the roof now my legs won't let me
Just a note this chimney was installed in 1978
8 in stainless steel insulated chimney and when scopes (camera)
in spring still looks like new. You take care of your chimney
and it will take care of you
 
Thank you. I guess i am baffled about it because my moisture gauge is reading 11-12% or lower on the stuff i have been burning. Granted like you said that's not taking a piece of that wood and splitting it in half and measuring right then but just on the end and face. Also i had my chimney cleaned in october. Is it fair to say that's not normal to have that much build up in such little time or are you all who are burning 24/7 cleaning it a couple times a year?
You are just reading the surface moisture when you need to know the internal moisture. You need to split a room temp piece of wood and test it on that face.

Also what stove are you running? What pipe temps are you running at? Even if your wood is dry running to cool will cause creosote issues
 
Yup, testing surface moisture and end grain is meaningless
 
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You are just reading the surface moisture when you need to know the internal moisture. You need to split a room temp piece of wood and test it on that face.

Also what stove are you running? What pipe temps are you running at? Even if your wood is dry running to cool will cause creosote issues
i am running a gemini wood burning furnace. not sure on pipe temps. I will be upfront and say it could be my lack of knowledge on how to operate the wood furnace (operator error). What i had been doing was running the damper decently wide open during the morning to get the house temp up and then close it more once i get to temp and then for overnight burns i have it partially cracked to keep the house temp fairly steady for a slow burn. Maybe that's not a good practice.
 
At 74 I clean from the inside
For years from the roof now my legs won't let me
Just a note this chimney was installed in 1978
8 in stainless steel insulated chimney and when scopes (camera)
in spring still looks like new. You take care of your chimney
and it will take care of you
So i have never myself cleaned a chimney. I want to be able to do that myself. If i may ask do you use a traditional brush type with the wires sticking out or a rotary/drill style that spins?
 
So i have never myself cleaned a chimney. I want to be able to do that myself. If i may ask do you use a traditional brush type with the wires sticking out or a rotary/drill style that spins?

Because my cleaning brushes were bought years ago I use the traditional nylon brush
with fiberglass rods. Works well for me but they say the soot eaters are really good
 
The rotary wheels on a drill such as the Soot Eater is what I've been using for years now with good results. I was skeptical at first so after I cleaned I had a chimney sweep inspect the job and he said was good to go.