Creosote Before and After the Cat

[leeave96]

I am still in the learning curve on my Woodstock Keystone on damper settings vs amount of wood in the firebox, size and quality of it.

Sometimes on a night burn, I cut the damper back a tad to much and the front glass darkens and I can see black shinny creosote on the firebox and especially the door.

After a brief time with a hot fire, the glass clears-up and the coating in the firebox goes away or turns to a very fine semi-light brown powder.

The cat is on during these smoldering overnight burns and I'm wondering what's going on downstream after the cat sees the smoke. Is the outlet side of the stove pipe and chimney much cleaner than the inlet side of the firebox or does it gloss-up with creosote with these slow burns?

Haven't pulled any pipe to have a look-see - just courious as to what you folks are finding.

BTW, my Keystone is giving me some great burn times overnight. 8 hrs is very easy with a stove top temp at 250ish in the morning with a good bed of red hot embers to rekindle the fire. Also, the ash pan is pretty slickery too.

Thanks!
Bill

 

[wkpoor]

I'm no expert but 250 stove top seems really low. That would explain the 8hr burn time. In my feeble mind I see it pretty simple. The more BTU's needed to do the job the hotter the stove the less the burn time allowing for other factors like density of the wood.

 

[BrowningBAR]

I'm no expert but 250 stove top seems really low. That would explain the 8hr burn time. In my feeble mind I see it pretty simple. The more BTU's needed to do the job the hotter the stove the less the burn time allowing for other factors like density of the wood.

You miss-understood. He is saying the stove temp is 250 when he gets up in the morning after an overnight burn

 

[Backwoods Savage]

leeave96, it sounds to me as if your wood is not quite as dry as it should be. This does have the advantage of longer burns but you will not be able to extract all the heat out of the wood that you could if the wood was really dry. It is good that the hotter burns cleans the glass but seeing the shinny creosote in the stove should worry you a bit. This should send an automatic caution your way to be checking the chimney often....much more often than most folks even think about. Every month is not too soon to check, especially in the first year of burning and perhaps also in the second year.

I believe we just had one case on this forum of someone burning only 2 weeks and the chimney was already really bad. This is not good and the only remedy is to get some dry wood to burn. It is also up to every wood burner to know what dry wood is else if you buy, any seller can tell you a cock and bull story stating how good their wood is, how long it has seasoned, etc.; and they do.

For the time being, even though you will not be able to hold those long fires, you do need to burn the stove hotter than normal just to keep from plugging everything with creosote.

Good luck.

 

[Slow1]

As long as the cat is engaged and active it "Should" be burning all the various hydrocarbons that would contribute to the creosote formation. I also get the buildup on the inside of my stove, but so far I have not had issues on my glass - I think the wood I've been burning this year is dryer than last year. But even so with a low burn the inside of the door and some parts of the stone in the box will get black/shiny/etc.

After a year of burning my chimney was fine and my cap looked much better overall than it did my first year burning (different stove - not a cat stove) so I think it is fine.

Now - the caution I will put in here is that you do want to be sure your cat is up to temp when you engage so you don't smoke things up. If you don't see the cat temp climb right quick at the start (well, as quick as it can on top of the stone) and get well above that 250 mark then you have a different issue.

wkpoor - as to the 250 surface temp on top; in the morning that is not bad at all for 8 hours. Most likely the temp is higher most of the night during the burn (but only Bill can answer that for sure). I burned last night starting at around 6pm - 3 splits of pine and some chunks of hardwood. This morning (6hrs later) surface temp was 150 and there were coals enough to coax a fire to start but not really a 'drop splits in and walk away" level. House stayed warm - peak temp on the burn was around 500 and I suspect much of the burn was around 400 as this is where it was cruising at 10p. I choked it down to between .5 and .75 so that it would burn longer vs dumping all the heat early in the evening. Glass was clean, but the stove had that "smoky" smell inside and there was 'gunk' on the inside of the door and corners of the stove.

So Bill - I think you are likely doing great there. If you want to avoid the smoked glass in the AM consider burning a little hotter. Perhaps engage cat a little later, then burn at a higher air setting for a little while then bring it down to your cruising air setting for the night. I think this helps to get the firebox up to temp and stable before you choke it down. Also, it seems that I have yet to find wood that is 'too good' or 'too dry' - every bit that is better dried the better it burns. This pine I have is almost 2 years stacked and I can almost light splits with a match.

 

[leeave96]

wkpoor - Yes, my stove top temp of 250ish degrees is at the end of an overnight burn and that, according to Woodstock, is a 500 degree internal stove box temp - so I'm doing pretty good there.

Dennis - I've got great wood to burn. I cut my own wood and the reason I point that out is that I know the condition of my wood vs. taking the word of someone that sells "seasoned" wood, but infact is not seasoned at all. I don't cut any green or near green wood, only dead wood that has been dead for a long time and then it is stacked and allowed to further season/dry out. 95 percent of my wood is oak and locust. I have been burning wood or been around it for over 40 years and while my wood is not aged in a woodshed for 3 years, it is the best I (and my family) has ever burned. Bottom line is - I got really good wood to burn.

FWIW, so far, the smoke on the glass has been from seasoning my new stove and on the occasion when I go to far in cutting down the damper as I learn where the limits are on my stove burn. Since my seasoning fires, the glass has been fairily easy to clean - but, the Keystone has a larger glass area than the Fireview. Where the glass gets dirty the most is on either side of the andirons, from the bottom of the glass to about where the arch in the glass begins. The top of the glass across is pretty clean and the glass between the andirons is really clean from top to bottom. All of the glass seems to stay clean (or becomes clean) after a hot burn. I imagine the difference in what some are seeing on their Fireviews (vs my Keysone) is due to it's smaller width glass and that glass being in the center of the stove vs extending out to the corners of the stove and so I would expect the Fireview glass to always be cleaner than the Keystone just because of the smaller width of it.

Speaking of glass, one of my stove selection lessons learned is that it's a lot easier to clean a door with glass on it vs. a fixed plane of glass like my woodstock has just due to being easier to access.

Slow1 - I think you hit the nail on the head. If you have a really smoldering burn, you are going to see creosote in the firebox and hopefully if your cat is engaged and active, the cat ought to burn-up the creosote going through it.

Another thing to consider with regards to creosote getting past the cat is the rate of burn. For example if you have the stove cranking with green or not so seasoned wood, the amount of air coming into and out of the stove could overwhelm the cat. The velocity of the air moving out of the stove could carry unburned creosote past the cat. However, on a smoldering burn, the air velocity through the cat ought (hopefully) to be slow enough to allow the cat to burn-up the creosote on it's way out of the stove and have a clean burn - even with less than desirable wood. I should think this would justify the claim that cat stoves are great for low/slow clean burns.

Anyhow - I'm looking forward to giving this stove some time and seeing how the stove pipe/chimney looks in a few weeks or a month and courious as to what others are finding too.

Thanks!
Bill

 

[corey21]

wkpoor - Yes, my stove top temp of 250ish degrees is at the end of an overnight burn and that, according to Woodstock, is a 500 degree internal stove box temp - so I'm doing pretty good there.

Dennis - I've got great wood to burn. I cut my own wood and the reason I point that out is that I know the condition of my wood vs. taking the word of someone that sells "seasoned" wood, but infact is not seasoned at all. I don't cut any green or near green wood, only dead wood that has been dead for a long time and then it is stacked and allowed to further season/dry out. 95 percent of my wood is oak and locust. I have been burning wood or been around it for over 40 years and while my wood is not aged in a woodshed for 3 years, it is the best I (and my family) has ever burned. Bottom line is - I got really good wood to burn.

FWIW, so far, the smoke on the glass has been from seasoning my new stove and on the occasion when I go to far in cutting down the damper as I learn where the limits are on my stove burn. Since my seasoning fires, the glass has been fairily easy to clean - but, the Keystone has a larger glass area than the Fireview. Where the glass gets dirty the most is on either side of the andirons, from the bottom of the glass to about where the arch in the glass begins. The top of the glass across is pretty clean and the glass between the andirons is really clean from top to bottom. All of the glass seems to stay clean (or becomes clean) after a hot burn. I imagine the difference in what some are seeing on their Fireviews (vs my Keysone) is due to it's smaller width glass and that glass being in the center of the stove vs extending out to the corners of the stove and so I would expect the Fireview glass to always be cleaner than the Keystone just because of the smaller width of it.

Speaking of glass, one of my stove selection lessons learned is that it's a lot easier to clean a door with glass on it vs. a fixed plane of glass like my woodstock has just due to being easier to access.

Slow1 - I think you hit the nail on the head. If you have a really smoldering burn, you are going to see creosote in the firebox and hopefully if your cat is engaged and active, the cat ought to burn-up the creosote going through it.

Another thing to consider with regards to creosote getting past the cat is the rate of burn. For example if you have the stove cranking with green or not so seasoned wood, the amount of air coming into and out of the stove could overwhelm the cat. The velocity of the air moving out of the stove could carry unburned creosote past the cat. However, on a smoldering burn, the air velocity through the cat ought (hopefully) to be slow enough to allow the cat to burn-up the creosote on it's way out of the stove and have a clean burn - even with less than desirable wood. I should think this would justify the claim that cat stoves are great for low/slow clean burns.

Anyhow - I'm looking forward to giving this stove some time and seeing how the stove pipe/chimney looks in a few weeks or a month and courious as to what others are finding too.

Thanks!
Bill

Same problem here i had creosote in 2 weeks. Come to find out that my chimney was to short creating poor draft therefor a lot of creosote. I have added 4 feet to my chimney height.

 

[North of 60]

I run a smoldering fire in my stove most of the time during this shoulder season. Yes my fire box soots up but cleans itself up after a fresh load on high before I shut it down to smolder it again. So what if I was to have a stove fire with the creosote. ;-)
Down stream of the CAT in the flue still looks like the gray in the tailpipe of a clean running car. As it gets colder out I will have more flame which is more heat in the outside flue to prevent the condensing, therefore still keeping a safe clean chimney.

 

[Todd]

Bill,
I get the same thing in my Keystone. The door and back gets some shinny stuff on it during low burns and it will disappear with a hotter burn. I burn the same 3 year old wood in my Fireview and I never see the shinny stuff but can get some crusty powder on the door or inside back. I also noticed the Fireview's glass stays much cleaner at low burns for some reason. I went up on the roof today to extend my Keystone chimney and looked down both flues and they were clean so I feel pretty comfortable the cat is doing it's job.

Another thing I have noticed about the Keystone unlike the Fireview, there is not 2 layers of soapstone on the right side of the stove where the door is located, so if you look through the glass the left side looks closer to the glass and air wash than the right side. It only looks like 3/4" thick stone and even thinner where the cast iron door is located. Maybe the air wash doesn't hit that right side wall as good as the left and causes some creosote on the door and also on that back panel? Most of my left over coals are on that right side as well.

Here are a couple pics of the creosote in that right rear gap.

 

[leeave96]

Todd,

I haven't noticed creosote in that corner - just didn't jump out at me, but I'll take a look. Definately got it on the lower back wall and on the door, but it burns off with higher temp burns.

Bill

 

[ecocavalier02]

i get some crap on the back wall when burning low but thats it.and ive been burning a lot of crap stuff to get rid of it as well. my glass stays spotless. i just burn hot for a half hour or less. then crank it down over the course of an hour and no problems.

 

[leeave96]

Bill,
I get the same thing in my Keystone. The door and back gets some shinny stuff on it during low burns and it will disappear with a hotter burn. I burn the same 3 year old wood in my Fireview and I never see the shinny stuff but can get some crusty powder on the door or inside back. I also noticed the Fireview's glass stays much cleaner at low burns for some reason. I went up on the roof today to extend my Keystone chimney and looked down both flues and they were clean so I feel pretty comfortable the cat is doing it's job.

Another thing I have noticed about the Keystone unlike the Fireview, there is not 2 layers of soapstone on the right side of the stove where the door is located, so if you look through the glass the left side looks closer to the glass and air wash than the right side. It only looks like 3/4" thick stone and even thinner where the cast iron door is located. Maybe the air wash doesn't hit that right side wall as good as the left and causes some creosote on the door and also on that back panel? Most of my left over coals are on that right side as well.

Here are a couple pics of the creosote in that right rear gap.

Todd,

I let my stove burn out today and this evening I took a look at the corner and door and there is similar creosote build-up in that same recessed corner at the door hinge, but my creosote only goes up to about an inch past that bolt (or what ever it is) as you show on your pic. Also the lower corner of the door and the warning plate in that area has some creosote on it too.

The thing that gets my attention is the cresote on the door as it is in my face when I reload and sometimes it is black with creosote and other times it is a powdery flake/dust.

I've got a low burn going tonight - for my overnight burn with orange embers beneath the wood and an orange cat going above the wood, no flame. My damper setting is on 3/4. I think this is about the lowest I can go without the cat starting to dim as well as the embers doing the same.

Bill

 

[North of 60]

I've got a low burn going tonight - for my overnight burn with orange embers beneath the wood and an orange cat going above the wood, no flame. My damper setting is on 3/4. I think this is about the lowest I can go without the cat starting to dim as well as the embers doing the same.

Bill

IF ya dont need the heat its OK to turn it down and have the CAT not glow.

 

[fdegree]

I'm having a similar problem...all four corners, inside the stove, look like the picture. The glass also turned very dark. This is after burning 24/7 for 1 week. I know my wood is not dry enough...around 20% - 30%

I have inspected the pipe connection on the stove, and it is only a very thin layer of brown powdery, flaky stuff. Yesterday, I removed the cap and looked down the pipe...same thing, a very thin layer of brown powdery, flaky stuff.

Considering my wood condition, is there anything I can do to reduce this build-up inside the stove?

 

[Todd]

Bill,
I get the same thing in my Keystone. The door and back gets some shinny stuff on it during low burns and it will disappear with a hotter burn. I burn the same 3 year old wood in my Fireview and I never see the shinny stuff but can get some crusty powder on the door or inside back. I also noticed the Fireview's glass stays much cleaner at low burns for some reason. I went up on the roof today to extend my Keystone chimney and looked down both flues and they were clean so I feel pretty comfortable the cat is doing it's job.

Another thing I have noticed about the Keystone unlike the Fireview, there is not 2 layers of soapstone on the right side of the stove where the door is located, so if you look through the glass the left side looks closer to the glass and air wash than the right side. It only looks like 3/4" thick stone and even thinner where the cast iron door is located. Maybe the air wash doesn't hit that right side wall as good as the left and causes some creosote on the door and also on that back panel? Most of my left over coals are on that right side as well.

Here are a couple pics of the creosote in that right rear gap.

Todd,

I let my stove burn out today and this evening I took a look at the corner and door and there is similar creosote build-up in that same recessed corner at the door hinge, but my creosote only goes up to about an inch past that bolt (or what ever it is) as you show on your pic. Also the lower corner of the door and the warning plate in that area has some creosote on it too.

The thing that gets my attention is the cresote on the door as it is in my face when I reload and sometimes it is black with creosote and other times it is a powdery flake/dust.

I've got a low burn going tonight - for my overnight burn with orange embers beneath the wood and an orange cat going above the wood, no flame. My damper setting is on 3/4. I think this is about the lowest I can go without the cat starting to dim as well as the embers doing the same.

Bill

Your probably fine. I get the same, depends on the load and type of burn.

Do you have a pipe thermometer? It's a good tool for when you turn it down to low burn. If your external pipe temp during the majority of the burn is over 250 chances are the internal temps are over 500 and the cat is working. Also check for smoke out your chimney, it's a sure sign.

 

[North of 60]

I'm having a similar problem...all four corners, inside the stove, look like the picture. The glass also turned very dark. This is after burning 24/7 for 1 week. I know my wood is not dry enough...around 20% - 30%

20% to 30% MC is your problem. Dont be complaining when you start having issues with your CAT. I would say its looking pretty good under the circumstances as you are running a boiler for the 1st hour after a reload.
YES you are being punished.

 

[fdegree]

I knew I was going to have some issues this year, with the wood condition. Next year, my oak will have been seasoning for about 20 months...hopefully things will be better then. After these first 2 years of burning, I will be on a schedule that will result in 2.5 years of drying for each season...but first, I have to get past this year, and next.

Should I clean the Cat more frequently? Maybe monthly...

 

[North of 60]

I knew I was going to have some issues this year, with the wood condition. Next year, my oak will have been seasoning for about 20 months...hopefully things will be better then. After these first 2 years of burning, I will be on a schedule that will result in 2.5 years of drying for each season...but first, I have to get past this year, and next.

Should I clean the Cat more frequently? Maybe monthly...

I dont think cleaning the cat will be the issue. Damaging the CAT by shocking it would be the result. All that moisture flashing off and travelling through the combuster causing it to crumble. From a liquid to a gas has an expansion rate of 1600 times. That will be rapid expansion and cooling at the same time as it meets the front surface of the CAT. I think after reload's it would be a good idea to have the CAT in bypass mode for a longer period to rid a good part of that moisture. The only down side is that your flue will collect more nasties that will require more frequent check-ups. Obviously your burn times will reflect also. My 2 cents anyhow.
Cheers and i am pullin for ya.

 

[nate379]

I would not worry much about it guys. Just take a scraper and clean it out when you empty out the stove every couple months or whatever.

8hr burn time on low is horrible! Sounds like something is wrong with the wood or the stove. To compare, I put close to a full load in my stove last night. Now I could have probably put in another 2 or 3 pieces if I played Tetris, but I don't pack it in that tight! I did that around 5PM and today at noon once I raked around the small unburned chunks there was plenty of flames to catch the fresh wood on fire right away.

 

[Slow1]

I would not worry much about it guys. Just take a scraper and clean it out when you empty out the stove every couple months or whatever.

8hr burn time on low is horrible! Sounds like something is wrong with the wood or the stove. To compare, I put close to a full load in my stove last night. Now I could have probably put in another 2 or 3 pieces if I played Tetris, but I don't pack it in that tight! I did that around 5PM and today at noon once I raked around the small unburned chunks there was plenty of flames to catch the fresh wood on fire right away.

What stove are you burning? If you put it in your signature then folks won't have to ask

 

[ecocavalier02]

the cut offs and crap wood im burning now arent the best but they still catch good and fast i let it get going good then burn on 3 for 15 20 min. then 2.5 or a little lower for another 15 then 2 for a little then down to 1.5 no black glass an plenty of heat. also like to reload on a little bit bigger than normal coal bed not huge but a good one to get them raging quick.

 

[nate379]

Blaze King.

I would not worry much about it guys. Just take a scraper and clean it out when you empty out the stove every couple months or whatever.

8hr burn time on low is horrible! Sounds like something is wrong with the wood or the stove. To compare, I put close to a full load in my stove last night. Now I could have probably put in another 2 or 3 pieces if I played Tetris, but I don't pack it in that tight! I did that around 5PM and today at noon once I raked around the small unburned chunks there was plenty of flames to catch the fresh wood on fire right away.

What stove are you burning? If you put it in your signature then folks won't have to ask

 

[North of 60]

Blaze King.

I would not worry much about it guys. Just take a scraper and clean it out when you empty out the stove every couple months or whatever.

8hr burn time on low is horrible! Sounds like something is wrong with the wood or the stove. To compare, I put close to a full load in my stove last night. Now I could have probably put in another 2 or 3 pieces if I played Tetris, but I don't pack it in that tight! I did that around 5PM and today at noon once I raked around the small unburned chunks there was plenty of flames to catch the fresh wood on fire right away.

What stove are you burning? If you put it in your signature then folks won't have to ask

In one eye and out the other. :lol:

 

[nate379]

Have no idea what that means! I'd say it must be a Canadian thing but I used to be one so can't be that!

 

[North of 60]

Cmon Nate, I GIVE UP will be the last thing I add to my signature here. One more time, What stove are ya running?