Expert help despiratly needed: Why can't I solve the creosote problem?

[begreen]

It seems like it's burning too cool. Damp wood will do that.

Do you have a stove thermometer to monitor the stove temps? If yes, can you describe in a step by step fashion the burning cycle as you are running the stove?

Also, can you get some perfectly dried wood and run with it for a week or two on that wood?

 

[Cord]

Ok, here is the cat. This really suprised me. The cat is totally plugged. I don't even understand how the stove could continue to burn like this. The ash is very loose and fluffy. I could easily blow the cat out with compressed air. I don't know if this thing is any good though. Havn't seen a bad one yet to know the difference. Remember, this cat was installed at the begining of the last season. I was meaning to check it after the flue liner was installed, but I never got around to it. The other pic is of the chamber below the cat. On the right side I believe is some insulation that seems to have worn away. The sloped material on the left is the same fine ash that is plugging the converter. The ash is the worst on the left side, but it does fill the entire chamber. The area above, where the damper is, is also totally white and covered with a fine layer of ash. As soon as you get to the cast iron pipe elbow the ash turns to heavy black creosote. You can literally draw a line between the two colors.

 

[Cord]

Ah, yes moisture levels. I borrowed my neighbors moisture meter last night. The results suprised me. The "dry wood" has been under a metal cover that is open on 3 sides for better than 3 years. We moved this wood into the garage in late summer. That wood measured between 12-18% moisture. Most of it was below 15%. The oak has been outside under a tarp. It snowed just a couple of days ago so I knew the moisture levels would be pretty high. Nothing was less than 22% and many peaked the meter at 25%. This wood is seasoned so now that we have it in the garage it should dry out pretty quickly.

Firing procedure:

Stove is hard to get lit. I will fill the fire box with a large quantity of very dry sticks that are around 1/2" to 2" in diameter. These are set on a bed of balled newspaper. I then put a couple of pieces of balled newspaper in the ash tray below the grate. I lite the newspaper below because it really makes a dramatic difference in the draft. Despite the mfr's warnings, we need to leave the ash tray open for a while to really get the fire to flash off. Once the sticks start to coal I will then add one or two medium sized pieces of split wood. By now the ash tray is closed. We let this burn wide open for a while until the stove is starting to put off heat. We then load the box. Let it burn wide open for a couple of minutes and then turn the converter on and reduce the air control. With the air control around halfway open (it's thermostatically controlled) we see around 300-400 degrees of flue temperature. This temp will continue to reduce as the creostote builds up. Before I took these pics we were only seeing 100 degrees of flue temp, even though the control settings never changed. I never let the temps get into the red zone or above 400 degrees.

How does a converter thermometer work? Do I need to drill the stove? Is it like a candy thermometer?

 

[Corie]

It sounds like a combination of weak draft and not letting the catalytic combustor reach operating temperature before closing the air control. The latter portion is just an assumption, but everything you've said so far, particularly above this post, shows you have WEAK draft.

You have an insulated 6 inch liner and still have a weaksauce draft like that? hrmm. Maybe you need to add some height to that stack. You're sure that the bozo installer insulated the liner, correct?

 

[Cord]

I put that question to him yesterday and he said that it was. I'm meeting him on Thursday to review the installation and the problems.

How can I determin how strong the draft is?

 

[Corie]

Well, a qualified installer should have a draft meter. Get him to measure your draft and see where its at. I believe there are industry standards for how strong the draft should be. Elk should be able to chime in and give the exact values.

 

[Andre B.]

How can I determin how strong the draft is?

Probably more then you want to know about chimneys.
(broken link removed to http://energyconcepts.tripod.com/energyconcepts/chimneys.htm)

While the smallest stack in the chart is 100' high and 36" diameter the formulas and basic physics still apply to small stuff.
_____________
Andre' B.

 

[elkimmeg]

Pressed for time now but I know where y many of your problems are

 

[Mo Heat]

... wood measured between 12-18% moisture. Most of it was below 15%.

Just to be certain, did you split the wood and test the middle, or did you test the outside?

Firing procedure:

Stove is hard to get lit. I will fill the fire box with a large quantity of very dry sticks that are around 1/2" to 2" in diameter. These are set on a bed of balled newspaper. I then put a couple of pieces of balled newspaper in the ash tray below the grate. I lite the newspaper below because it really makes a dramatic difference in the draft.

It looks like you have a bunch of fly ash choking things down. I'd recommend you stop using newspaper. It produces a lot of ash and may be contributing to your clogged combustor issue. You can do all sorts of other things to start a fire. An easy one is to saw, cut, or somewhat cleanly break a wafer off a wax log and use it (or half of it) instead of the paper. Or buy the slightly more expensive fire starter blocks that come about 20 to a box. They'll both burn for a good 15 minutes or longer and easily get the type kindling you're using going quickly. I hate using newspaper to start fires because of the enormous ash content. Just be sure that you allow the wax wafer to be completely consumed before engaging the cat (to avoid cat poisoning). Which brings me to my next question and suggestion.

How long a time is there between your post kindling stage (when your bigger logs are burning well) and when you engage your cat? Without a cat thermometer, err on the safe side and burn your first group of splits all the way to the coal stage (this is important), then add another group of splits and wait until they are all really rolling in flames before you engaged the cat. And don't reduce the primary air for another 15 - 30 minutes on that load. I'd only load the stove about half full (maybe 15 - 20lbs of wood) for the first post kindle load, doing the same for the next load you put onto the first load's coals. At least an hour of serious burning should pass to be sure you are up to cat light off temp.

... we see around 300-400 degrees of flue temperature. ...
... I never let the temps get into the red zone or above 400 degrees...

Those are pretty good flue temps IF, and I repeat IF, you are measuring the outside of the pipe near the exit of the stove. If you are using a probe thermometer that tests inside the pipe, then they are about half as impressive.

You've got a pretty long horizontal run there. And a ninety degree elbow that reduces your effective chimney height. You need to calculate the loss and make sure you have enough effective vertical chimney height for that stove using 6" pipe. Elk can tell you what to subtract for the horizontal run + the 90* elbow.

Be sure an sweep all the crap out of the chimney and flue exit, and clean that cat, before you start firing that stove harder or you might have a chimney fire. You should NOT use compressed air on the cat according to most cat mfr recommendations. I know some people do it, but it can be touchy. A can of compressed air like you use for a camera will blow the fly ash out (most likely). To get creosote off you may need to perform the somewhat messy and involved procedure using a warm water a vinegar solution as per the cat mfr recommendations. Someone can point you to that procedure, I'm sure.

How does a converter thermometer work? Do I need to drill the stove? Is it like a candy thermometer?

Most VC cat stoves have a pre-tapped hole in the rear to allow you to spear a cat thermometer probe into the exhaust side of the cat chamber. If your's has that you'll lilely see a metal plug on the back of the unit. If not there, it could be tuff. Cast iron is hard to deal with for the DiY'er.

There's a lot of suggestions here, I don't feel like repeating to summarize, but hopefully you can gleen them with a reread. Good luck.

 

[Corie]

Cord,

No offense to you, but do you live near any of us? Maybe one of us could come by and look things over? Watch you light a fire, etc.

 

[Mo Heat]

One more general observation.

Your stove (and mine) are from a generation back. They are mostly cast iron with no primary fire box refractory material. This means that the massive amounts of cast iron are sucking heat from the fire like nobody's business. My stove is near 500lbs of heat sucking iron. Yours is likely close to that or the same. So it takes a whole lot more fire (or time) to get efficient combustion going in the fire box, and even more to get all the iron surrounding the cat chamber hot enough to light that cat off. It takes your cat element around 500*F (ballpark) to light off. And it is usually insulated in air, or in my case a refractory box, that actually is meant to protect the cast iron from the intense cat heat, but also serves to insulate the cat from the initial cast iron heat that makes it work. So you've got a lot of thermal inertia to overcome before that cat will want to cooperate and light off. Be patient. Get it hot. Once it lights off, nearly zero creosote will get past it. Guaranteed. I'd bet it's not lighting off. But you may also have an accompanying weak draft issue that I addressed in the last post.

Once you get it to light off, then you'll just want to be sure to warm up a new load before reengaging it.

If you get another stove, you might want to consider the newer non-cat secondary combustion. You don't need to worry about all this cat stuff with those. Cat stoves aren't for everyone. But, on the other hand, if you get to where you can reliably light the thing off, then you are over the hump, and you will likely love your cat stove. But I've been wrong before.

 

[Cord]

We live just north of Milwaukee, Wisconsin. If anybody wants to stop buy, I'd be more than willing to cover a consulting fee.

Mo-The wood has been split for years. I generally split the wood green and then stack it for a year or two. The moisture was measured at the cut end of the log. This meter did not have probes so we could not measure the split face.

What is a "wax log"? Never heard of that term. We only use the paper to light the fire, then the fire burns for weeks. Is the newspaper what is really clogging that cat? I thought that maybe we let the fire box fill up with too much ash. This stove has a very small ash pan and the slots in the bottom are a bit too fine. You have to actually rake out the fire box or it will fill up with ash.

Cat engagement is no where near as long as you are recommending. Not even close.

Flue temps are being measured on the horizontal pipe apx. 12" away from the stove. Elk, can you get us that dimension Mo mentions? Are you suggesting the compressed air would damage the cat or the oil/water in the air would damage the cat? Your post reads that if I can clean the cat, that it is still usable.

I don't recall seeing a tapped hole in the back. I take it the hole would be above the cat chamber. I know what you mean by having to drill cast iron.

500lbs did feal about right last night. Two of us couldn't even pick it up. And yes, this is my first ever cat stove. Guess I was burning it like the steel plate non cat stoves that I grew up with.


Can you guys recommend a cat thermometer? Anybody carry one in their store? If I have to drill the cat chamber, where should I locate the hole? This time, I'm going to make sure that dang thing is lit!

 

[Corie]

It just seems impossible that you're getting cat light off with creosote accumulation like that.

My dad and brother, who are not exactly wood stove whiz kids managed to suffer through an old dutchwest cat stove, sometimes running with the cat not engaged, sometimes forgetting to let the cat lit off, etc. Even after a cord of their mediocre usage, I still only got a coffee can of creosote out of the chimney.

I wish I lived closer because I'd love to stop by and help. Its kinda my thing.

 

[Mo Heat]

... The moisture was measured at the cut end of the log. This meter did not have probes so we could not measure the split face.

So many mysteries here. Measuring moisture on the outside of the split will be inaccurate. I can't picture your meter with no probes, so I guess I won't know for sure what is going on with your wood moisture unless you can split a split, and I mean right now, now a year ago, and then measure the moisture content on the face of the freshly revealed surface. My moisture meter has probes so I take a split off the pile, split it in half again, lightly poke scribe holes with the meter probes, take an ice pick and make a goodly hole, then insert the moisture meter probes. That's accurate. I'm not sure what you are doing and without being there probably never will be. A picture is worth a thousand words and all that.

What is a "wax log"? Never heard of that term.

I'm talking about a Duraflame brand log or the generic store equivalent from Walmart, etc. They are made from parafin wax and sawdust mostly, and probably contains some strange chemicals. Thus, wax log. Sorry for the generic description.

We only use the paper to light the fire, then the fire burns for weeks. Is the newspaper what is really clogging that cat? I thought that maybe we let the fire box fill up with too much ash. This stove has a very small ash pan and the slots in the bottom are a bit too fine. You have to actually rake out the fire box or it will fill up with ash.

Could the the paper, might be the other ash, but I always leave an inch or more of ash covering the cast iron grate to protect it and I don't have any such ash problems. The newspaper creates more 'fly ash' that can easily become airborn and get sucked into the cat area. Wood (and wax log wafers) create less 'fly ash' and more dusty or powedery ash.

One of the things I don't like about the stovecombustors.com elements is the non-honeycomb design. My first thought when I saw one of them was, "Gee, looks like that thing will get clogged up quick." Elk and DavidV have used them with success, but they are both seasoned wood burners. I like the honeycomb design. That way, only fly ash will clog them. With non-honeycomb designs, any ash at all can clog them because any ash that gets onto one side stays on that side, it doesn't just blast on through like with the simpler see-through honeycomb design. This will likely fuel a debate I've been seeking to avoid, but there it is.

Cat engagement is no where near as long as you are recommending. Not even close.

That's a problem. Maybe your only problem. You should know soon enough if you try my above suggested firing technique. The initial light off is the most critical and the most difficult. Even watching my digital cat thermometer I've seen it take as long as an hour for things to reach a temperature that insures cat light off in less than a minute, which is my minimum goal. I can usually get my cat to light off in around 30 seconds, that's when I know it was truely hot enough and minimal fouling occurred. Once it lights off, it will clean itself up by burning off any creosote. But if you cover all the catalyst metals with creosote you might be lucky to get things hot enough to clean the cat via heat, and may need to remove and clean with vinegar.

Flue temps are being measured on the horizontal pipe apx. 12" away from the stove.

Again I ask, is it a surface (magnetic) thermometer or a probe (penetrates pipe) thermometer?

Are you suggesting the compressed air would damage the cat or the oil/water in the air would damage the cat?

Probably both. But I'm really just quoting what I've read from the cat manufacturers.

Your post reads that if I can clean the cat, that it is still usable.

Yes. It should be good as new once you get it clean somehow.

I don't recall seeing a tapped hole in the back. I take it the hole would be above the cat chamber. I know what you mean by having to drill cast iron.

I think on that stove the exhaust side of the cat is actually below the cat element, but I'm not sure. Maybe you can see it in the online manual at the VC website.

Can you guys recommend a cat thermometer? Anybody carry one in their store? If I have to drill the cat chamber, where should I locate the hole? This time, I'm going to make sure that dang thing is lit!

This thermometer was actually designed for your stove (and mine). I would be surprised if your back plate isn't pre-tapped for it, but I guess it depends on how old it is. I have one of these and love it, although I recommended one to Todd and he didn't seem to care that much for it. I also bought a cheap power supply with 9-volt adapter from Radio Shack. Otherwise it eats batteries nearly as fast as you can put them in there.

(broken link removed to http://www.condar.com/9-85.shtml)

 

[elkimmeg]

Cord read threw this post I think you will realise part of your problems
https://www.hearth.com/talk/threads/4821/

 

[Mo Heat]

... if Cord waited to kick his cat in, wouldn't he be better off with the cast iron since it should cool slower too?

47

 

[Mo Heat]

Here are the numbers:

Subtract 5 feet of chimney for each 90 degree turn.

Example: If you have a 10 foot chimney with two x ninety degree elbows, your effectively chimney height is zero.

The minimum pitch of a horizontal run is 1/4” per foot. Going up, of course.

 

[Cord]

Cord read threw this post I think you will realise part of your problems
https://www.hearth.com/talk/threads/4821/

Um, I don't recognize that "refractory package" as something I've seen on my stove. The pic didn't post well, but I do see what could be refractory material. It's below the combustor, against the fire box and has the appearance of being severly eroded. There is nothing where the cat slides in. It kinda stays up by it's own good will until I can get the back cover on. Then it's pinched between the cover and and something behind. The sides are open. I notice this refractory package is for a new stove though. I'll need to get my model number tonight.

I'm having the chimney swept on Thursday. I'll try your light bulb test then. Do you guys have a better source for stove gasket? I replaced the gasket on the lid at the start of this season and it already has chuncks missing. While things are cold I'll replace it again.

The temps are read with a surface mounted thermometer.

 

[JMF1]

As far as the creosote leaking from the bricks and "puddling" on the hearth...........did the installer clean the flue BEFORE installing the liner? Sounds like a basic practice to me but how would that much creosote be getting out of a new liner? Just a thought...........

 

[elkimmeg]

I promise before the night is out to address your situation, but go back to the pictures you posted your refactory package is gone useless

 

[elkimmeg]

used Vermont Castings Defiant Encore. This stove dates to the mid 80’s and has a catalyitic converter

That year we go into a severe problem with glazed creosote. The creosote was actually penetrating the chimney lining and staning the exterior brick. It was dripping down the flue and pooling behind the stove on the hearth.

There were also some gaps in the flue lining that dated back to the homes construction some 60 years before. We had a 6” insulated liner installed this past summer.

We have been firing the stove for almost 2 months now and were forced to shut it down because of a minor chimney fire. Thankfully we were around to monitor the fire and were able to shut things down before they got out of hand. Looking at the chimney cap from the ground I can see that the openings are around 50% plugged with wet looking creosote. There are creosote stains running down the masonry cap. I also noticed moisture coming through the brick which is a new issue I have not seen before. We always burn the stove with the converter on and the converter was replaced last year. Tonight I will be removing the converter to check it, but I suspect it will be OK.

My earlier post
you never mentioned a damper block off plate? Another reason for their use. It prevents cooler room air from entering the chimney and cooling the chimney and creating the conditions of accelerate Creosote build up.

Some wood split can hold moisture a long time up to years. I also suspect, that a split of two that is not quite dry gets in the mix. Remember once creosote build up starts the accumulations
Continue build up. You have to examine you burning procedures, including allowing more spacing between splits. Take a few of your slit and split them again and see if you can detect moisture..

Corie is correct if you were running you cat stove correctly there it would combust smoke so efficiently that there would be little left for creosote to build up

I cut and pasted some of the previous discussion then looked at your pictures
First of all the chimney had previous glazing which penetrated the bricks and all crevices at no time was it mentioned that it was cleaned, so the danger of creosote still exist with the voids in the existing liner and no insulation. Once that chimney extends beyond the insulation envelope of your home, these voids cracks are potential streams of cold airflows to cool that liner. The liner is also being cooled by room air being able to flow up that chase with the liner further cooling off the un-insulated liner No block off plate?
Once that chimney exits the roof it now is really cold note the creosote in the cap and dripping on the bricks.

That sum up your chimney situation, but the problem also exists in the stove, a stove 20 years old. Picture 3 details the condition of your refractory package. Parts of it are non-existent, deteriorated over the 20 years of use, this is common. Without the proper channeling of secondary smoke and exhaust, the cat is not functioning. If it were, there would be little left of smoke to from creosote By dampering down and no secondary combustion threw the cat you are producing a creosote factory The evidence is there.
Because you are producing some heat that old glazed creosote melts threw the cracks and crevices and now is dripping or weeping
Showing outside the bricks. Each time you run that stove the creosote builds up more. Even your cap is 50% plugged and dripping on the outside bricks.

You have done the right thing stop using the stove you have to extract as much creosote on your existing clay and bricks as possible. Then install the insulated flue you paid for.
The stove is in no condition to be run safely you can either repair it or start over with another stove. Its not the Cat or the manufacturer its 20 years of use without maintainance and replacement parts
You have to identify the model from the real label plate I can help you to rebuild it, but that choice is yours. It takes a bit of mechanical ability. You are right that stove should be cranking like my Encore

 

[Mo Heat]

I suspect that's a good call elk. I was making what seems now to be an erroneous assumption that the stove was in sound working order.

I'm not sure how much has been invested in old stoves so far, but Cord might want to bite the bullet and buy a reasonably priced new fangled stove like the Englander BB is running through it's paces. Isn't that the same stove that Rob_of_Wisconsin installed last year?

New can be a fine thing when it's priced right and if BB's happy with an Englander, I'll bet Cord would be too. Otherwise, an entire rebuild may be in order. Me, I think I'd start over if I could afford it. Sometimes you spend more money by trying to save it. Cord already has a 6" SS chimney liner in place. I'll bet an Englander would hook right up to it. End of problem.

Might even be able to get a few bucks on the scrap iron market for the VC and find someone here to buy his combustor for 60% off.

 

[Cord]

This stove is in too good of condition to throw on the curb. I have a receipt that shows the refractory package and cat were replaced in 99. When I got this stove, the owner cautioned me that it was proably due for a cat. Wish he had also mentioned the refractory package as it would have save me a $1,800 flue liner. My local dealer wanted $380 for the cat and refractory package and could not give me a delivery date. The refractory package on ebay in Elks other post is not the correct part number for my stove. 5004600 looks to be the correct part. 30001152 is the cat. My stove might be model 0028, but that's an educated guess. Mfr. date is around 1987. I'm willing to put a new refractory element into the stove, but I need to find one for hopefully a bit less money.

No, the existing clay liner was not cleaned. That creosote was NOT coming off. Even a chain flail wasn't going to touch it. The space between the liner and the clay liner is supposed to be insulated, though I question how the insulation was capped. Once that snow melts and I get up there, I know that I will not be satisified with how he terminated the liner insulation. I will get that corrected.

 

[stoveguy2esw]

hey cord,
im going to defer to elk on the stove's condition , he is much more familiar with that brand of unit than i am. i got lost in the "forest for the trees" as well looking past the stoves condition (didnt know at the time) and thought you had a cold air intrusion cooling your flue. looking at your liner connection i do see a problem with connection to one of our englander stoves , that being you will need a rear flue unit and unfortunately we do not produce one. we do have an insert that would likely work , but your installation as it sets would probably be a more favorable match to a VC unit with a rear flue connection such as you already have. the hull to me looks pretty good , elk would be better suited to tell you whay to do with the inside , i dont know their guts as well. as for the 20 year old design it worked like a champ 20 years ago when it was state of the art and im sure with the proper parts and maintainance that old girl will shine.

mike esw

 

[elkimmeg]

Cord good news you already have the cat that' one expense you do not have to deal with.
Hey any out there got a craper Encore 0028 model I can take apart to learn how and put back together I got the resolute acclaim down

1987 is the 0028 model Might as well get it out to the garage, Way too ash dusty to do this in the house.

I'll bet when the guy replaced the cat in 1999 he damaged the refactory package also know as the dog house and never said a word
Whils at it you should replace some gaskets which you will encounter the flue collar the damper and there may be some on the refactory package plates
the damper anf flue collar adapter are 5/16" or 3/8" Another thing is to start soaking the bolts with PB blast not onec but twice a day id possible and give them a rap with a hamer to shock them soak them rap them soak them Might as well get a head start possibly by the time it comes to taking them off they will spin right off in the mean time might as well get some high temp black paint and a gasket kit for your doors the glas ans ashpan once apart it is easy to pain that stove up and make it look new a Restored 0028 Encore has netted up to $1100 on Ebay.
do the light test and blow tha sucker and vac it out Also it might be easier to take the top offf to get at the doghouse and re caulk the interior seams and joints.
Done right this stove can preform like new for many years to come.

Here is where most got their parts and a picture of the exploded view I will try to get some pages of the service manual to share with you. there is going to be another member doing the exact same repair/ rebuild at the same time. It will help to share info and we can help others in the future