Lots of stage 2 Creosote in thimble....

[MichaelAL]

Hi all,

I just used a soot eater type product to clean my liner after burning my new jotul f400 for it's first ever season (liner was new this past year too). The stove sits on my hearth and there is a 90 degree thimble connecting the stove to the liner which runs straight up a 30 foot or so chimney.

When I removed the bottom cover of the thimble, a LOT of creosote crystals fell out. So much that the thimble must have been nearly full of the stuff (which seems not great). In hindsight, there were times when I heard what sounded like a "raining" sound inside the liner from time to time, particularly shortly after starting a new fire. I put about 2 cords of wood through the stove over the winter.

Is this normal? Concerning? I am certainly going to pop that bottom cover off once a month or so this coming season to prevent it from building up so much, but am trying to get more info on whether I have a bigger issue.

The rest of my cleaning produced not even half as much of these crystals as were just sitting in the bottom of the thimble.

Thanks for any guidance gang!!

 

[bholler]

Hi all,

I just used a soot eater type product to clean my liner after burning my new jotul f400 for it's first ever season (liner was new this past year too). The stove sits on my hearth and there is a 90 degree thimble connecting the stove to the liner which runs straight up a 30 foot or so chimney.

When I removed the bottom cover of the thimble, a LOT of creosote crystals fell out. So much that the thimble must have been nearly full of the stuff (which seems not great). In hindsight, there were times when I heard what sounded like a "raining" sound inside the liner from time to time, particularly shortly after starting a new fire. I put about 2 cords of wood through the stove over the winter.

Is this normal? Concerning? I am certainly going to pop that bottom cover off once a month or so this coming season to prevent it from building up so much, but am trying to get more info on whether I have a bigger issue.

The rest of my cleaning produced not even half as much of these crystals as were just sitting in the bottom of the thimble.

Thanks for any guidance gang!!

Can you post some pics? I don't really understand what you are referring to when you say a bottom cover on your thimble

 

[MichaelAL]

Can you post some pics? I don't really understand what you are referring to when you say a bottom cover on your thimble

Yes, here you go. Sorry I tried to include this in the original post but couldnt find the 'attach' option. I undo that single screw and remove that bottom cover.... Edit: I guess 'cap' is a more accurate word for what I removed. I took that off and went straight up that opening with the soot eater.

 

[begreen]

Ah, that it the liner tee cap. The raining sound may have been creosote burning in the liner. How was the wood dryness last season? What temperature was the stovetop with a typical fire?

Is the liner insulated? How tall is it?

 

[bholler]

It could have also just been creosote falling down as the liner expanded. Is the liner insulated?

 

[MichaelAL]

Ah, that it the liner tee cap. The raining sound may have been creosote burning in the liner. How was the wood dryness last season? What temperature was the stovetop with a typical fire?

Is the liner insulated? How tall is it?

I don't *think* the liner is insulated. This was installed within a pre-existing chimney flu that was built in 1999/2000. Below is how the liner was itemized on my invoice from the installer:

1 K-VENTING-WOOD INSERT - 6" Wood SS Liner kits

I have a basic rutland magnetic thermometer on the top of the stove and average fire temp was 400-500 degrees.

I did not check moisture rating on my wood but it is all NE hardwood that was cut down 2+ years ago. Though I havent gotten around to putting it into a shed yet, so it was getting rained on. I live in Rhode Island.

And the liner/chimney is around 30 ft high. It is a first floor installation in a two story house.

 

[begreen]

OK. Good responses, they provide some clues. First, most liner installations require an insulated liner in order to comply with code. Then there are confounding factors. first being the length of the liner. The flue gases are going to cool down a lot over 30ft. That's another reason for an insulated liner. Was the wood split and stacked 2yrs prior? If it was top-covered then it probably is ok. If the wood was cut down 2yrs ago but only split last year, then it may not have had enough time to fully dry out.
The stove top temps sound average, though our Castine liked to cruise around 600-650F with gradually declining temps as the wood burned down.
Is this an exterior wall fireplace or interior?

 

[Woodsplitter67]

Though I havent gotten around to putting it into a shed yet, so it was getting rained on.

I think part of the problem is the quality of your wood. You should get a moisture meter and test a split on a fresh face. You will be surprised on how much waters in it. If its getting rained on its most likely above 20%
If you dont have enough room in the shed, racks and top covered will get you by. If your wood is still sitting out, you need to get it under cover now, in rows to let it dry. extra water in you wood will help cool things down and with 30ft of liner that makes things worse, so regarding your wood.. the dryer the better. That will make for a cleaner stove pipe..

 

[kennyp2339]

What's your definition of "a lot" is it a coffee cans worth, 1 gal bucket, 5 gal bucket? Like @bholler state, it could have been expanded creosote that fell and collected, I know you said you cleaned the whole chimney, but please go outside with binoculars and check to make sure the cap is clean and free of debris

 

[MichaelAL]

BeGreen, my installer is a highly reputable (and not inexpensive) company around here, so I am guessing they used the insulated liner but I have emailed them the question to be sure. I am going to get a wood moisture meter to check that once and for all. I have also been hemming and hawing about a wood shed, and this experience is pushing me over the edge... The fireplace is exterior and there are three flus in it if that matters (one for the oil burner and one for another wood fireplace in the house that never gets used)

What's your definition of "a lot" is it a coffee cans worth, 1 gal bucket, 5 gal bucket? Like @bholler state, it could have been expanded creosote that fell and collected, I know you said you cleaned the whole chimney, but please go outside with binoculars and check to make sure the cap is clean and free of debris

 

[MichaelAL]

What's your definition of "a lot" is it a coffee cans worth, 1 gal bucket, 5 gal bucket? Like @bholler state, it could have been expanded creosote that fell and collected, I know you said you cleaned the whole chimney, but please go outside with binoculars and check to make sure the cap is clean and free of debris

The initial load immediately upon removing the tee cap (so before I even put the cleaner up the pipe) filled 1/4 to 1/3 of a 5 gallon bucket. Once I cleaned the liner I got maybe half that amount again. I see people saying they get a cup or two when they do theirs so I am getting WAY more than that....

 

[kennyp2339]

The initial load immediately upon removing the tee cap (so before I even put the cleaner up the pipe) filled 1/4 to 1/3 of a 5 gallon bucket. Once I cleaned the liner I got maybe half that amount again. I see people saying they get a cup or two when they do theirs so I am getting WAY more than that....

Yea that is a lot for only going through two cords of wood, now as we enter fall time and things are drying out, take a few random splits and resplit them, test the fresh face with a moisture meter (lowes - $30.00) you want to be between 15% - 22% for optimum wood, you can burn up to 25% but at that point you need to burn with the air control up, and you will be fighting short burn times, less heat output and creosote build up.
Also since your only entering your second season it would be wise to clean you chimney after every cord, this will give you an idea of how your doing and if you need to burn hotter or can lessen the air intake and let it ride for same heat output but with longer burn times.

 

[Ctwoodtick]

Harbor Freight has a good, small moisture meter. Usually around $10. Consistent readings with my more expensive one.

 

[Highbeam]

30’ of flex liner in an exterior masonry chimney will make a lot of creosote in the best of times. Especially if the stove is burned part time with lots of warm ups vs constantly hot. Creosote is normal, we all get it and most of us that burn full time can measure the annual amount in quarts, not cups, and most of us have half as much chimney as you to sweep.

I’m more interested in the color of the accumulation. Brown and matte is good, black and glossy not so good.

 

[Ctwoodtick]

Also important is consistency of the build up. Light fluffy almost powder like he’s more favorable over flaky crunchy thicker stuff.

 

[begreen]

BeGreen, my installer is a highly reputable (and not inexpensive) company around here, so I am guessing they used the insulated liner but I have emailed them the question to be sure. I am going to get a wood moisture meter to check that once and for all. I have also been hemming and hawing about a wood shed, and this experience is pushing me over the edge... The fireplace is exterior and there are three flus in it if that matters (one for the oil burner and one for another wood fireplace in the house that never gets used)

By process of elimination, it's not the stove. We had a Castine several years ago. It was a clean burning stove with a typical amount of creosote after burning 3 cords of about a cup or too of soot and sote. However, there was one year when we had some wet maple and that created a couple quarts of sote after just a month of burning. With dry wood, the F400 burns quite cleanly.
If not the stove, it's the liner, the wood or how the stove is being operated. Getting a moisture meter is a good first step. General makes an inexpensive one that works well. Remember that to test the wood, it needs to be resplit, then tested on the freshly exposed face of the wood.
Is there a block-off plate in the damper area? If not, there should be.

30’ of flex liner in an exterior masonry chimney will make a lot of creosote in the best of times

Especially if it is uninsulated.

 

[MichaelAL]

30’ of flex liner in an exterior masonry chimney will make a lot of creosote in the best of times. Especially if the stove is burned part time with lots of warm ups vs constantly hot. Creosote is normal, we all get it and most of us that burn full time can measure the annual amount in quarts, not cups, and most of us have half as much chimney as you to sweep.

I’m more interested in the color of the accumulation. Brown and matte is good, black and glossy not so good.

It was all black, shiny crystals. I had read somewhere that this is known as Stage 2 creosote.

 

[MichaelAL]

By process of elimination, it's not the stove. We had a Castine several years ago. It was a clean burning stove with a typical amount of creosote after burning 3 cords of about a cup or too of soot and sote. However, there was one year when we had some wet maple and that created a couple quarts of sote after just a month of burning. With dry wood, the F400 burns quite cleanly.
If not the stove, it's the liner, the wood or how the stove is being operated. Getting a moisture meter is a good first step. General makes an inexpensive one that works well. Remember that to test the wood, it needs to be resplit, then tested on the freshly exposed face of the wood.
Is there a block-off plate in the damper area? If not, there should be.

Especially if it is uninsulated.

There is no block off plate (just insulation around the liner), and I am awaiting an answer from the retailer/installer on whether the liner is insulated. I will post another closeup pic of the liner above the thimble, maybe one of you can determine whether it is insulated from this?

I have ordered a moisture meter and will see how my wood is... I am also in the process of building an 8x12 shed so will have that within a month.

Lastly, on stove operation: last season I would frequently restrict the air flow down to 1/3 open or so for two reason. 1) if the stove runs at 500+ degrees full-time the house gets too hot 2) burn times are extremely short at fully open....

I am concurring with the group that less than perfectly dry wood is likely my biggest issue, more research is forthcoming.

Thanks all.

 

[begreen]

You could just pull out the insulation to inspect the liner. Then stuff it back up there. Wear a mask. Is that regular fiberglass insulation or more like white kaowool?

One would rarely run a modern EPA stove wide open. That is not only inefficient and waste, but it also puts a lot more heat up the flue instead of in the stove and room. Throttling down a secondary burn stove actually makes it burn hotter due to secondary combustion that kicks in when the primary air is reduced. Closing down the primary air causes the vacuum created by draft to pull air from the secondary ports. That's why the fountain of fire, secondary light show when the air is reduced.

In milder weather when you want less heat, burn fewer splits at a time.

 

[Woodsplitter67]

Hi all,

I just used a soot eater type product to clean my liner after burning my new jotul f400 for it's first ever season (liner was new this past year too). The stove sits on my hearth and there is a 90 degree thimble connecting the stove to the liner which runs straight up a 30 foot or so chimney.

When I removed the bottom cover of the thimble, a LOT of creosote crystals fell out. So much that the thimble must have been nearly full of the stuff (which seems not great). In hindsight, there were times when I heard what sounded like a "raining" sound inside the liner from time to time, particularly shortly after starting a new fire. I put about 2 cords of wood through the stove over the winter.

Is this normal? Concerning? I am certainly going to pop that bottom cover off once a month or so this coming season to prevent it from building up so much, but am trying to get more info on whether I have a bigger issue.

The rest of my cleaning produced not even half as much of these crystals as were just sitting in the bottom of the thimble.

Thanks for any guidance gang!!

Just a thought on the wood to put things in perspective. Let's say we both load our stove with 50lbs of wood.. mine is at 15%MC and yours is at 25%MC That means for evey 50lbs you burn you put 5 lbs more water up your stove pipe. If a cord of wood weights 3K thats 60 50lb loads of wood at 5lbs per load is 300 lbs of additional water going up your stove pipe per cord cooling down you stove pipe or you can look at it like about 800 grown men pissing down your stove pipe.. How ever you want to look at it... Its alot of liquid.

 

[MichaelAL]

Just a thought on the wood to put things in perspective. Let's say we both load our stove with 50lbs of wood.. mine is at 15%MC and yours is at 25%MC That means for evey 50lbs you burn you put 5 lbs more water up your stove pipe. If a cord of wood weights 3K thats 60 50lb loads of wood at 5lbs per load is 300 lbs of additional water going up your stove pipe per cord cooling down you stove pipe or you can look at it like about 800 grown men pissing down your stove pipe.. How ever you want to look at it... Its alot of liquid.

Quick update: I just got my moisture meter and checked my leftover wood from last season. It is all under 20%, so is definitely ready to go now; but I'll bet it was a lot higher last year. Anyway, just wanted to thank you all for the suggestions and ideas. I will be sure to clean my chimney with each cord this coming season to see how it is going with dryer wood. If I need to make a switch to an insulated liner, that may be on the table as a second stage resolution.

Can't wait for that first chilly evening to fire up the stove again!

 

[Ctwoodtick]

Did you test the wood directly after splitting it? If not, you’ll get artificially very low readings.

 

[Woodsplitter67]

Did you test the wood directly after splitting it? If not, you’ll get artificially very low readings.

I was going to ask the same question.. was this on a fresh split face.. and about room temperature..

 

[Ctwoodtick]

Rhode Island has been basically at room temp so that will help.

 

[MichaelAL]

Rhode Island has been basically at room temp so that will help.

Yes I know that is the proper way to test the moisture content. I hadn't done that the first time around. I just did now and got a bunch of readings anywhere from 17 - 25% depending on the species and size of the split. Also, it has been hot, rainy, and humid as anything here the last 2 days, so that likely is not helping anything. I do feel this wood is fully ready to go this coming winter.