creosote

[carinya]

I have a 26' tall masonry chimney. It's in centre of house & was built 25 years ago. I have a kent tile fire manufactured July 86. Has no secondary burn. Am thinking about a new stove. My question is "What will produce the least creosote buildup (if any) on the chimney - cat or non-cat ?" With the Kent I usually clean out about two thirds of a grocery sack of crud at the end of the season.

Thanks for your unbiased opinions !

Steve

PS If my picture comes thru .... (taken jan 7) try rotating a quarter turn clockwise

 

['bert]

I will start, seeing that this was your first post, welcome there is so much very good information here. Others may correct me but I do not think that cat vs no cat will have any bearing on creosote build up. Dry wood and proper burn technique will have the most impact on any creosote build up.

Most of the newer EPA type stoves will keep your creosote build up down to a min if burnt hot with dry wood. I do not have a cat in my stove so do not know that much about them, but the ones who do know should be along shortly.

 

[carinya]

Thanks for the welcome,AB

I need to make a correction to my post. Instead of "no secondary burn" I should have written "no secondary air". These early Kents are super simple.

My neighbours have cat stoves and metal flues out of the top of the stove - whatever is in the flue seems to fall back down into the stove. They don't seem to need to clean out.

I have a metal flue rising 3' from the top of the stove then a 90 degree elbow into the masonry chimney. I have a flue temp probe (at about 2' above the stove) that I usually take up to 900 degrees & then try not to let fall below about 400' - but falls lower if no-one around or the house is warm enough.

One decision I'm looking at is whether to put in a metal flue , rising straight up from the Kent, & bypassing the masonry chimney or invest in a new stove & keep using the masonry chimney.

The Kent gets a nice burn but doesn't have that secondary air input which all the new non-cats seem to have. It has a nice simple construction . The only moveable/replaceable parts are the damper to re-route airflow and the door.

I think my wood is generally dry. And I wonder if most of the crud in the chimney builds up in the Spring with small fires to take the chill off the air.

An opinion from Tom Oyen on how my old Kent compares to today's stoves might help

 

[Todd]

I agree dry wood is key, but you also need proper chimney. What size is your masony chimney inside diameter? Is it the same size as your stove exhaust outlet? You could reline it with stainless liner if it doesn't meet the specs of the stove.

 

[carinya]

Chimney - inside specs 7.5" x 7.5" Thimble entry is 6" dia which is stove exhaust size.

I've ruminated about reline but how do you manouveur everything into place inside the chimney at the 90 degree turn at the thimble ?

 

[karri0n]

If you have that nice interior masonry chimney, I see no reason to bypass it completely and put a stovepipe up, not to mention a metal chimney coming out of the roof near where the masonry comes up can be tricky to meet with the 10-2-3 rule. The ideal setup would generally be a stainless steel insulated liner inside your masonry chimney.

That being said, with a 7.5" tile liner already in place, it can be pretty a pretty tight fit to get a 6" SS liner down through that. The cross section of your tile liner is 56.25²", and the cross section of a 6 inch exhaust is 28.26²". I don't remember what the recommended maximum difference in cross-section from exhaust to chimney is, but someone might pop in with that info.


As far as fitting everything through the thimble, it's likely that you would use a tee to connect the liner to the back of the thimble at the 90 degree bend. If you get your tile liner inspected and there are no cracks, I would think you could use a single wall uninsulated liner down through that, but it's likely you wouldn't be able to fit a double wall/insulated liner inside of the tile liner.

From the tone of your questions, I'm assuming you want to do the install yourself? You might talk to installers in your area do determine what the best setup would be regarding safety and performance. Many will work with you and give their advice and expertise if you are up front with them about wanting to do the install yourself.

 

[edthedawg]

karriOn - when you talk about the cross sectional area differences - are you thinking of leaving it direct venting w/ the 6" stovepipe straight into the crock? I think the OP was asking how to connect a thimble / tee essentially - all SS within the masonry up to the rooftop exit? The ratios given are on the edge of "OK" but I still think it would be much better to find a way to reline.

If it's a tile-lined, interior flue, there's no code requirement (that I've seen) to insulate. But even w/ a standard uninsulated 6" SS liner, I don't know how you'd drop it down w/ a Tee connector unless you could carve yourself some kind of cleanout access. I wouldn't necessarily trust leaving the cleanout cap off and hoping for the best w/ a cleanout door down below - those never seal well. And still - how do you fit it in / down / up to the right spot?

One thing to ask: is there anything else on this flue? an oil burner in the basement perhaps? is there a good cleanout door somewhere on this flue?

Also to answer one of the OP questions: Anything new will burn cleaner than your 1986-era dragon. That said, you're only pulling a gallon or so from 26' in a year - that sounds mostly pretty good for the device you're burning in...

 

[BrotherBart]

But even w/ a standard uninsulated 6" SS liner, I don't know how you'd drop it down w/ a Tee connector unless you could carve yourself some kind of cleanout access. I wouldn't necessarily trust leaving the cleanout cap off and hoping for the best w/ a cleanout door down below - those never seal well. And still - how do you fit it in / down / up to the right spot?

Virtually all liner kits come with two piece tees. You attach the barrel portion of the tee to the liner, drop in the liner, and then attach the snout of the tee from inside the thimble/crock from inside the house.

 

[SmokeyStover]

I burned a Tile Fire in my home for about ten years. It's a great stove considering the design is over 20 years old. The amount of creosote you mentioned is pretty darn good for the size and length of your chimney. I used to get about a 5 gallon pail full out of a 32' interior masonry chimney. There is a product out called Anti Creo Soot. It is a liquid catalyst creosote remover and works better than any of the dry products I have ever tried. When used regularly it is great way to prevent creosote build up.

 

[karri0n]

karriOn - when you talk about the cross sectional area differences - are you thinking of leaving it direct venting w/ the 6" stovepipe straight into the crock? I think the OP was asking how to connect a thimble / tee essentially - all SS within the masonry up to the rooftop exit? The ratios given are on the edge of "OK" but I still think it would be much better to find a way to reline.

If it's a tile-lined, interior flue, there's no code requirement (that I've seen) to insulate. But even w/ a standard uninsulated 6" SS liner, I don't know how you'd drop it down w/ a Tee connector unless you could carve yourself some kind of cleanout access. I wouldn't necessarily trust leaving the cleanout cap off and hoping for the best w/ a cleanout door down below - those never seal well. And still - how do you fit it in / down / up to the right spot?

One thing to ask: is there anything else on this flue? an oil burner in the basement perhaps? is there a good cleanout door somewhere on this flue?

Also to answer one of the OP questions: Anything new will burn cleaner than your 1986-era dragon. That said, you're only pulling a gallon or so from 26' in a year - that sounds mostly pretty good for the device you're burning in...

Well he was asking how the liner would be connected, and also weighing his options of lining, using the existing tile liner, or closing up the chim and installing a straight metal class a through a chase. I agree a full SS liner would be the best, but as long as the cross sectional differences aren't too major, and he's currently getting very little buildup with a smoke dragon, as long as the clay liner is in good shape, he might be ok. I don't think that's really considered a direct vent/slammer install since it is actually lined.

I agree cleaning could be an issue with any type of tee , unless you installed a rounded elbow instead of a tee and cleaned bottom up.

 

[Todd]

Your going to have a hell of a time connecting a tee snout in a 6" crock. It sounds like your current stove is drafting ok, if your thinking of a new stove, I recommend trying it in the chimney as is, as long as it's in good shape. If the new stove doesn't draft well, then think about relinning.

 

[carinya]

Thanks for your replies.

Some responses:

- There is nothing else connected to the chimney. Our house is built into a hill with poured concrete walls on north & diminishing on east & west. Plenty of glass on south. First floor is concrete and our living area. Upstairs are bedrooms and is woodframe.

- Thimble in chimney is 5' above floor - so there is a metal flue from stove to 90' elbow. I've notice same buildup in this flue as mentioned by BrotherBart in thread https://www.hearth.com/econtent/index.php/forums/viewthread/38659/

- Top of the clean-out is 2'4" above floor so there's a 2'8" or so distance to get to the tee cap at the bottom of a liner.....unless I extended the liner....

- Todd's remark "Your going to have a hell of a time connecting a tee snout in a 6” crock. is a bit of a worry. Anybody else with a comment on this ?

- My "dragon" Kent Tile " was the first clean burning non-catalytic stove widely sold in North America"! https://www.hearth.com/econtent/index.php/wiki/Kent_Tile_Fire/
Below is an ancient diagram of it's simple workings. Should I drill a small air hole or two to get a "secondary air" injection?

Thanks again for all your input & I did discover about the two piece tee after cruising the internet (they even have video's showing how to install a liner)

Steve

 

[SmokeyStover]

If you have that nice interior masonry chimney, I see no reason to bypass it completely and put a stovepipe up, not to mention a metal chimney coming out of the roof near where the masonry comes up can be tricky to meet with the 10-2-3 rule. The ideal setup would generally be a stainless steel insulated liner inside your masonry chimney.

That being said, with a 7.5" tile liner already in place, it can be pretty a pretty tight fit to get a 6" SS liner down through that. The cross section of your tile liner is 56.25²", and the cross section of a 6 inch exhaust is 28.26²". I don't remember what the recommended maximum difference in cross-section from exhaust to chimney is, but someone might pop in with that info.


As far as fitting everything through the thimble, it's likely that you would use a tee to connect the liner to the back of the thimble at the 90 degree bend. If you get your tile liner inspected and there are no cracks, I would think you could use a single wall uninsulated liner down through that, but it's likely you wouldn't be able to fit a double wall/insulated liner inside of the tile liner.

From the tone of your questions, I'm assuming you want to do the install yourself? You might talk to installers in your area do determine what the best setup would be regarding safety and performance. Many will work with you and give their advice and expertise if you are up front with them about wanting to do the install yourself.

The ratio of flue size to chimney is 1-3. The stack can be no larger than 3 times the flue outlet on the stove, so this situation is well within the standards. NFPA 211 states that all interior masonry chimneys maintain a 2" MINIMUM air space between the chimney block and combustable material. Unless you are positive the chimney has the clearance, an insulated liner with 0-0 clearance specs must be used to reline the chimney. I have doubts that an uninsulated liner would solve the problem anyway since the flue would still be prone to rapid radiational cooling and still likely to form creosote. The amount of build up is minimal. I have talked to many people who get that much in 2 weeks! As long as the creosote isn't glazing I would keep doing what you're doing. It sounds like this system, and the user are performing quite well. And give the Anti-Creo- Soot a try.

 

[carinya]

Yes, there is a 2" gap between the chimney block and the 2x6 yellow pine flooring on the second floor and also through the yellow pine ceiling.

 

[mike1234]

I have a 26' tall masonry chimney. It's in centre of house & was built 25 years ago. I have a kent tile fire manufactured July 86. Has no secondary burn. Am thinking about a new stove. My question is "What will produce the least creosote buildup (if any) on the chimney - cat or non-cat ?" With the Kent I usually clean out about two thirds of a grocery sack of crud at the end of the season.

Thanks for your unbiased opinions !

Steve

PS If my picture comes thru .... (taken jan 7) try rotating a quarter turn clockwise

That does not seem like a horrible amount of creosote to me. If you were burning one of the gasifier boilers, then it would be too much, but for a stove or furnace, it seems reasonable to me. If you are worried about it, clean it 1/2 way through the season.

By the way, the definition of dry wood probably varies until you become a member here, then all the "seasoned members" pound into our skulls that dry wood is wood that has been split and then has set outside in the sun for at least 2 full summers, or possibly more (there are a few exceptions depending on the wood). If you cut it this spring and burn it this winter, there is a good chance it is not dry wood. Before I was a member here, dry wood meant dead standing wood that I cut and split yesterday, or last month - but if you burn that, you will get creosote.

 

[Highbeam]

I had a similar situation when I bought my current home. An old, but certified, insert stove feeding a masonry chimney. I lined it right away when I moved in with a non-insulated liner. You don't need to insulate it unless your masonry chimney is bad. Well, the chimney had some cracks and the mason said to watch it so I decided to watch it be destroyed after the first full burning season. I removed the chimney and then installed a freestanding stove on a hearth with a new vertical Class A stainless steel chimney. Doing this has been great. The vertical pipe from stove to sky makes cleaning super easy and provides excellent draft.

Your stove might have been cutting edge when it was made but that was more than 20 years ago!

 

[BrotherBart]

By the way, the definition of dry wood probably varies until you become a member here, then all the "seasoned members" pound into our skulls that dry wood is wood that has been split and then has set outside in the sun for at least 2 full summers, or possibly more (there are a few exceptions depending on the wood). If you cut it this spring and burn it this winter, there is a good chance it is not dry wood. Before I was a member here, dry wood meant dead standing wood that I cut and split yesterday, or last month - but if you burn that, you will get creosote.

I have to fess up on this one. For thirty years I cut and split in the spring and burned the following winter. Seemed like it burned fine to me and I even argued with people here about it. This past season I burned nothing but over one year seasoned wood and burned a third less. And the mid-season chimney cleaning was a wasted exercise just out of habit. It really didn't need it.

Old dogs can learn new tricks. :red:

 

[carinya]

BrotherBart

Out of 407878 posts on this site I'm truly humbled by your 'fession on this thread !

I have to confess that I'm enjoying it less, climbing up onto the roof of the house & cleaning the chimney - even though it is only once a year. I haven't done it yet this year but I will be interested in the results because the wood I used was definitely seasoned two years.

 

[BrotherBart]

One of the biggest creosote creators with unlined chimneys is air leaks in the chimney. Make sure the clean out door on that chimney is sealed really well. Any cold air leaks just make for a whole lot of crud in the chimney. Those Tile Fires are supposed to be really clean burning stoves when ya keep'em burning hot with good dry wood.

 

[carinya]

I literally duct tape up the clean out door for the season. It wasn't designed for an air tight fit.

The damper rod travels across the top of the stove and enters through the collar. This is not an airtight fit. I have assumed that any air entering here would contribute to "secondary burn".

 

[mike1234]

By the way, the definition of dry wood probably varies until you become a member here, then all the "seasoned members" pound into our skulls that dry wood is wood that has been split and then has set outside in the sun for at least 2 full summers, or possibly more (there are a few exceptions depending on the wood). If you cut it this spring and burn it this winter, there is a good chance it is not dry wood. Before I was a member here, dry wood meant dead standing wood that I cut and split yesterday, or last month - but if you burn that, you will get creosote.

I have to fess up on this one. For thirty years I cut and split in the spring and burned the following winter. Seemed like it burned fine to me and I even argued with people here about it. This past season I burned nothing but over one year seasoned wood and burned a third less. And the mid-season chimney cleaning was a wasted exercise just out of habit. It really didn't need it.

Old dogs can learn new tricks. :red:

I learned about "real" dry wood this winter on this forum, while I was busy cutting next seasons wood, so I went ahead and cut 2009, and 2010 wood, so that at some point, I will be burning dry wood. It's hard work to get 2 years ahead, and my guess is that most of us who have burned less than 3 years are still working on less than dry wood. I have a bunch of dead standing wood that I cut and split this winter, so I think it will be close to dry, but I don't have enough of it for a whole season, will have to dip into the stuff that I cut that was not dead. Thanks to all those who keep teaching.

 

[thechimneysweep]

An opinion from Tom Oyen on how my old Kent compares to today’s stoves might help

While not quite up to today's standards, the 1986-vintage Tile Fire wasn't nearly as primitive as many of its contemporaries. It had an airwash for the glass and a secondary burn chamber that was efficient enough to score 11.8 grams/hr, as compared to the 40+ grams/hr output of most of that era's non-catalytic models. The Tile Fire was one of a handful of non-cats to waltz right through Oregon's 15 grams/hr non-cat standard without modification.

Two things Kent hadn't yet incorporated in their secondary burn chamber in '86 were a separate supply of preheated combustion air and insulation on top. Also, the draft control on the Tile Fire could be shut down all the way, which enabled an unwary operator to smolder the fire and extinguish the secondary burn. Finally, the Tile Fire's firebox wasn't refractory lined. Many of today's models incorporate some version of the basic Tile Fire design, with these modifications added to achieve a cleaner, more efficient burn.

Creosote forms as a result of the condensation of a water/particulate mixture, but the water soon evaporates away, so the buildup is all particulates. Today's non-cats average about 3 grams/hr, so, all things being equal, you should anticipate about 1/4 the creosote buildup as you experience with your 12 gram/hr Tile Fire.

 

[carinya]

Many thanks Tom.

From reading Hearth.com & chimneysweeponline.com I knew that you had a wealth of knowledge. I was mistakenly thinking the Kent was rated at about 7.5grams/hr so I'm glad you straightened me out on that one.

We also have the occasional problem, when the air outside is completely still and I haven't got the stove going at top burn rate, of smoke smell entering the house through the non-airtight front door (it was second hand back when the house was built & we get quite a bit of air infiltration - not that I'm bothered by fresh air, except when the chimney smoke falls rather than moving away from the house)

Below is a pic of the chimney protruding at the ridge of the roof. It only extends 20" above the ridge but we have never had a back-puffing problem.

Will a new stove, generally exuding less particulate, lessen this occasional smoke smell problem ? (I guess not if the secondary burn or catalytic is not engaging)

 

[BrotherBart]

You will be amazed how little smoke comes out of these stoves. When there is smoke. I replaced my two old stoves with non-cats and my wife laughs at me when I get upset about the little bit wafting skyward on cold starts. After that it is nothing but heat waves from the chimneys. Nothing to "fall" and leak back into the house from anywhere. For a while I was concerned because I could shine a flashlight up there at night and see "smoke". Until I realized it was just steam that you can't see when the sun is shining.

Neighbor was surprised when I told him I was still burning wood. With two stoves running pretty much all winter.

 

[carinya]

You will be amazed how little smoke comes out of these stoves. ..... nothing but heat waves from the chimneys. Nothing to "fall" and leak back into the house from anywhere.

Thanks for your encouragement to get a new stove :coolsmile:

Perhaps some folk will have suggestions at a new thread https://www.hearth.com/econtent/index.php/forums/viewthread/38697/