Kuuma Vapor Fire Creosote

[Mckennaelectric]

Hello all

This is my 2nd season with my VF and i have to clean my chimney at least 2 times a season. Pleaae see the pictures and maybe someone will see something wrong with it. I have spoken with the manufacturer and they suggested i leave a windowncra ked open in my basement but that did not help. I relined my chimney with a 6" stainless steel liner and dont have a chimney cap on it. I also check my wood and it is in the moisture specs usually on the low end.

Also if you look at the back of the stove picture there is a black tar type substance that comes out of the chimney pipe right from the stove. The video i watched said this is normal the 1st fire but it has happened numerous times.

Thanks for ant help!

Andy

 

[sloeffle]

I also check my wood and it is in the moisture specs usually on the low end.

How are you checking your wood ?

How long do you generally CSS after either buying your wood, or harvesting yourself ? Any idea the species of wood.

 

[Mckennaelectric]

this was just now fresh splits on both

 

[Mckennaelectric]

And all my wood is 2 seasons ond right now. I store it is a covered wood shed with open sides

 

[JRHAWK9]

Is your liner insulated?

The black liquid stuff is condensation that's running down. Water is a by-product of combustion....the more water in the wood, the more water that will be expelled through the chimney. If the chimney is too cold, this can cool the flue gasses too much which can cause this water to condense and run down instead of exiting the chimney as a vapor.

My first thought is your chimney may be too cold, which is causing the water vapor to condense.

Do you see extended time on pilot (computer on 'c')? How are your burn times?

One time I accidentally reversed the wires on the thermocouple and had them wired backwards and it caused the burn to be all out of wack. It was not going on pilot and I already had signs of creosote buildup only after a couple small fires. Having the TC wired with correct polarity AND having the wire itself not reversed is critical. The resistance in the two different colors of the TC wire are different and can not be swapped.


Are you re-spitting a split and checked the moisture on the fresh split face? If not, you are measuring the moisture on the surface of the wood and not the internal moisture, which will be higher.

 

[Mckennaelectric]

Is your liner insulated?

Just the top 3 feet. I installed the liner inside an 8" square liner and could not get any insulation around the pipe. I had to remove most of the clay liner to get the liner installed. Now to install the insulation you just add water to would cost me a fortune. If I removed the last of the clay liner I could wrap insulation around the pipe. Would this be something I should do? The chimney is between the house and garage. Not sure that makes a diffrence.

The black liquid stuff is condensation that's running down. Water is a by-product of combustion....the more water in the wood, the more water that will be expelled through the chimney. If the chimney is too cold, this can cool the flue gasses too much which can cause this water to condense and run down instead of exiting the chimney as a vapor.

My first thought is your chimney may be too cold, which is causing the water vapor to condense.

Do you see extended time on pilot (computer on 'c')? How are your burn times?

I usually am running the stove at the lowest setting and might turn it up a little from there. I will get a good 8 hour burn time but I usualy don't fill the stove to the max. I do see the controller go to "c" but not always.

One time I accidentally reversed the wires on the thermocouple and had them wired backwards and it caused the burn to be all out of wack. It was not going on pilot and I already had signs of creosote buildup only after a couple small fires. Having the TC wired with correct polarity AND having the wire itself not reversed is critical. The resistance in the two different colors of the TC wire are different and can not be swapped.

I will check this when I get home. I hope I didn't do this!!


Are you re-spitting a split and checked the moisture on the fresh split face? If not, you are measuring the moisture on the surface of the wood and not the internal moisture, which will be higher.


I am making a fresh split on the wood and checking the fresh face of the wood. As you can see in he pictures.

As far as insulating the chimney better there is only 2 pieces of clay liner still installed. That was an SOB to get the liner through due to having a small offset in the liner. Would my best option be to remove thise last pieces of clay liner, pull the liner out, wrap some insulation around it and reinstall it???


Thanks for the help!

Andy

 

[JRHAWK9]

One other thing you can check. Remove your heat exchanger cover and inspect the upper chamber area. You should see mostly white/gray fly ash everywhere (depending on how many cold starts you have to do, as daily cold starts are not as efficient or clean as simply re-loading on coals). It may turn a bit darker towards the back. If everything is operating properly, you should not see any creosote in that upper chamber. What did that chamber look like when you cleaned it after last winter? If the furnace is running correctly then I'd have to say the issue almost has to be the chimney/stove pipe.

I'd also try wrapping the stove pipe with insulation or running all double wall stuff to try to keep the gasses as warm as possible.

I'd take a peak at the heat exchanger area before doing anything with your chimney though.

 

[Birdsell36]

With the elbows, pipe, and BD I have a 10 foot run of single wall at a 20 degree angle and have a similar issue with condensation. I haven’t solved it yet but I am going to wrap my single wall pipe with a chimney insulation blanket (5-10ft sections sold on ebay) to keep the flue gasses as warm as possible before entering the chimney. You may get a suggestion for double wall but as you know that is tough because of the need for adjustable elbows and the BD.

I would recommend putting one of these underneath the collar in the near term.

If you bury the prongs in those fresh splits do you see 20%+ readings?

 

[Mckennaelectric]

When i checked the heat exchanger this fall there was harldly anything in there. I didnt even clean it out. I will take a picture of it tonight. As far as solid pipe i might be able to use that instead. The small offset in the chimney is not a lot and if i remove the last of the clay liner i think i should be able to get double wall through with not much issues.
What option would be better? Flexible liner with insulation or double wall? Would i still have to insulate the double wall?

Thanks

 

[brenndatomu]

Would my best option be to remove thise last pieces of clay liner, pull the liner out, wrap some insulation around it and reinstall it???

I would. The VF runs low stack temps anyways, and if you get much below 250* F before it exits the chimney, it'll condensate.
And If that is oak you are burning, it'll be better next year after 3 years CSS'd (3 years cut/split/stacked) that meter shows under 20%, but they also aren't always super accurate either...you could easily be over 20% still...which if you aren't running the furnace real hard, will again tend to make condensate.
I'd use double wall stove pipe to the chimney, then pull your liner and wrap it...if you'd rather stick with the stove pipe you have, then just buy some extra liner wrap and use it on the stove pipe.
Another thing you could do to raise the exhaust temp is to take the insulated baffles out (the ones that go in against the HX tubes) at least until cold weather hits and you can run it a lil harder. (assuming you have all the baffles in)
And from what you describe, you do not have the thermocouple wires backwards...that causes major operational issues, which it sounds like you do not have.

 

[brenndatomu]

And just to put this in perspective, if you load 40 lbs of wood (a nice medium sized load) and its 20% MC, that's 8 lbs of water, or 1 gallon! That's a lot of steam, since water to steam expansion rate is 1700:1 !! If you don't keep things hot enough to keep it as steam up and out the top, its gonna condensate and make creosote...gotta get your pipe and liner surface temps up (insulate)

 

[trx250r87]

Has your damper been calibrated? If so what kind of draft are you seeing?

Eric

 

[Mckennaelectric]

Will this produ t work or are there better options?

Chimney Liner Flue Pipe Blanket Wrap Insulation Kits - Pour-Down Insulation | Rockford Chimney Supply - Rockford Chimney

Rockford chimney liner insulation kits help ensure safety and efficiency for stainless steel flex chimney liners. You can also use stainless steel flex liner insulation to reduce the build up of creosol and to help your chimney stay cleaner longer.

www.rockfordchimneysupply.com

As far as the remaining clay flue can i bust the remaining part out? I cant imagine i would still need the clay flue

Thanks for all the help!!

 

[Mckennaelectric]

Also would this produ t be an option to install on the single wall pipe i have installed in my basement? Instead of double wall stainless pipe down there?

and as far as my damper calibration i spike with the manufacturer on it and he helped me. It never does open but he made it sound like fine tuning is not very critical

 

[Highbeam]

Only partial loads and on low the whole time. Uninsulated liner, 10' of single wall.

I would agree that the liner must be insulated especially since you broke out most of the clay liner. As I understand it the clay liner and masonry structure must be 100% for you to not use an insulated liner. With an insulated liner, the old masonry stack is just there to hold it in place.

Double wall interior pipe, the black stuff, will help too since your run is so long and the BD introduces cold air to an already cold exhaust stream.

You need to adjust the BD to provide the correct draft to the furnace.

 

[gthomas785]

The BD can introduce a lot of cold air into the flue which can cause creosote. If it never opens, you may not need it.

 

[brenndatomu]

Will this produ t work or are there better options?

Chimney Liner Flue Pipe Blanket Wrap Insulation Kits - Pour-Down Insulation | Rockford Chimney Supply - Rockford Chimney

Rockford chimney liner insulation kits help ensure safety and efficiency for stainless steel flex chimney liners. You can also use stainless steel flex liner insulation to reduce the build up of creosol and to help your chimney stay cleaner longer.

www.rockfordchimneysupply.com

As far as the remaining clay flue can i bust the remaining part out? I cant imagine i would still need the clay flue

Thanks for all the help!!

Yes, the 1/2" stuff is what you want...and yes, it works fine on the stovepipe too.
Yes, take the rest of the clay flue out.
These guys brought up the draft...an insulated chimney will draft better too, but I wonder if you have changed the setting on the baro?
The marks on there will get you in the ballpark, but the only way to know where you're at for sure in with a manometer...an inexpensive one that works well is a Dwyer mark II model 25...can usually find NOS on ebay for $20-40 most of the time. (just make sure you get the red gauge oil with it, its a lil pricey to buy separately)
Even before getting a manometer you could try running higher draft...set that baro up closer to the "6" mark (so back one more mark from where its at in the pic there)

 

[brenndatomu]

The BD can introduce a lot of cold air into the flue which can cause creosote. If it never opens, you may not need it.

Comes with the furnace and required by the manufacturer...and doesn't cause an issue when everything is working right.

 

[brenndatomu]

and as far as my damper calibration i spike with the manufacturer on it and he helped me. It never does open

Hmm...if it never opens then I wonder if you even have enough draft to make this thing work right? I had noticed in your pics there that the chimney doesn't look very tall...that just means that the insulation is that much more important...gotta keep the flue gasses as hot as possible clear to the top. Low draft could certainly be part of the issue here!
My baro is open almost from the time I strike a match...but I do have a 27' chimney though too...

 

[brenndatomu]

As I understand it the clay liner and masonry structure must be 100% for you to not use an insulated liner

Correct, without the masonry there anymore, building code requires a minimum of 1/2" insulation wrap on that liner now...and even without the code, I wouldn't sleep too well without it!

 

[JRHAWK9]

Hmm...if it never opens then I wonder if you even have enough draft to make this thing work right? I had noticed in your pics there that the chimney doesn't look very tall...that just means that the insulation is that much more important...gotta keep the flue gasses as hot as possible clear to the top. Low draft could certainly be part of the issue here!

I was thinking the same thing.

 

[Mckennaelectric]

Thanka for all the input! I really appreciate it. I decided to shut the unit down until i can make this right. Can i connect the liner straight to the black pipe or should i purchase one of these? It looks like this would make it harder to clean?

 

[brenndatomu]

Traditionally you would use a tee like that...how is it that you could flex the liner enough to come through the wall...is the chimney cavity huge? And how would you attach it?
Don't think that liner would slide into black pipe either (you have to go male into female, headed down toward the stove, so that any flammable creosote stays in the pipe, instead of running out at the joints)
I'm not saying that you won't be able to find a stainless steel (every part of the liner assembly has to be SS) elbow that clamps properly to the liner, and then also fits inside the stovepipe, but I kinda doubt it, at least without ordering and returning a whole slew of them...
Keep in mind too that if you get too creative on this and something bad happens, you may be opening yourself up to the HO insurance company having an out on the claim.
How do you have the liner attached now?

 

[JRHAWK9]

I relined my chimney with a 6" stainless steel liner and dont have a chimney cap on it.

So there is no cap on this? Do you have a cleanout tee or something where it goes through the wall that will allow for any rain to drain out into the bottom of the chimney before it runs down your stove pipe and into the collar of the furnace? This is maybe a dumb question, as I have never saw or dealt with liners, so I don't know what is the proper way to do such a thing. In a typical masonry chimney, don't they typically go right down to the basement floor and have a clean out door at/near the bottom?

Growing up we had a masonry chimney and I used to help my dad clean it every winter, as we had a wood stove down the basement. I got to be at the clean out door and watch for when the tool he used got to the cleanout door. Then he would release something and the metal "fingers" would spring out and he would drag it up all the while these fingers scraped the creosote off the walls of the chimney.

 

[sloeffle]

Growing up we had a masonry chimney and I used to help my dad clean it every winter, as we had a wood stove down the basement. I got to be at the clean out door and watch for when the tool he used got to the cleanout door. Then he would release something and the metal "fingers" would spring out and he would drag it up all the while these fingers scraped the creosote off the walls of the chimney.

My dad had a burlap bag filled with rocks and other burlap bags ( I think ) in it that he would use to clean our masonry chimney with. I can remember having to help him, I would generally hold the ladder for when he would get off and on the roof.