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

[Cord]

We have owned our home for around 6 years now. When we first purchased the home it had a traditional open front fireplace with a steel lining. The fireplace was not very effective and was starting to rust so we removed it and had a new masonry suround built. The damper was also removed. In it's place I installed a cheap Franklin stove that never produced much heat. The next year we removed the Franklin and installed a Chinese copy of a Jotul stove. I only realized it was a copy during it's installation or I wouldn't have bothered. The stove wasn't producing much heat and had some glazed creosote problems which I blamed on the stoves origin.

When the stove cracked from being over fired I replaced it with a used Vermont Castings Defiant Encore. This stove dates to the mid 80's and has a catalyitic converter. The stove is installed in front of the brick surround with the pipe coming out of the stove horizontally. The horizontal pipe is around 18" long. Originally, the pipe then turned upwards and transitioned into the original clay liner. The liner was 8x10 physically. This was a bit large, but was listed on the mfr's web site as being an acceptable flue size. 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. We stopped firing the stove early in the season and started to save our pennies.

Everybody out there said that we needed to reline the chimney because of the excessive flue size. 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. The stove was reinstalled this time using the mfr's reducing coupler for a 6" liner. The stove can be used with a 6" pipe, but the stove can not be fired with the front doors open. A different, more modern chimney cap was installed to terminate the liner. Because of the difficulting in installing the liner, he was not able to insulate it immediatly. He tried to talk us into not insulating it, but we insisted and he came back a couple of weeks later to finish the job. I have not been up on the roof to inspect the termination and can't right now due to 8" of snow on the roof.

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.

At the start of the season, I was seeing 300-400 degrees of flue tempurature with the air control around halfway open. In a couple of weeks that temperature dropped and now I only see a couple of hundred. I believe the reduction in temperature is due to the creosote build up. Our wood is very well seasoned and most of it is stored in the garage. The garage wood is a mix of Elm, Maple, Silver Maple, Bass Wood, and Choke Cherry. Admittedly, not the best wood for buring, but it's very dry. We also have some Black Oak that is stored outside under tarp. The Oak, although seasoned, has a higher moisture content because of the way it's being stored.

None of the stoves that we've had over the years have really heated the home very well and all have created excessive amounts of creosote. This stove we currently have should be cooking us out of the home, but it barely gets us to above 70 degrees. The burn times seem to meet the mfr's listing, but we are shoving way too much wood into the stove for the amount of heat it's putting out. At this point I really don't know what else to try. We truly need an expert to come out and see what element I've missed in trying to solve the creosote problem. We live in Milwaukee Wisconsin if somebody wants to stop out. If you can think of a solution, by all means post it, but I can't see what else remains.

 

[wg_bent]

I know you said your burning dry wood, but it sure sounds like your burning green to me. Sorry if this sounds obvious..but you closing the CAT bypass damper?

I agree that stove should be seriously hot.

 

[Cord]

I guess I could borrow a moisture meter to test the wood. I will try to do that tonight. I know the wood inside will be very dry. That wood was stored under a metal cover for several years. Late in the summer we then moved the wood into the garage. This stuff hasn't seen rain for at least 3 years. The oak is moist. No question about it. We moved some of the oak into the garage yesterday, but it will take a couple of weeks for the moisture to drop.

Well, we are flipping the lever and the mechanism feels like it is functioning. I'm pulling the cat tonight and I will double check the mechanism.

 

[Eric Johnson]

Like Big E says, small, hot fires once or twice a day will help keep it clean. You might want to clean the chimney before you get into that routine, however. If you torch off a hot one with a dirty chimney, you might torch it off, too.

 

[Cord]

Could it be technique? We traditionally put 3 or 4 pieces of wood into the stove and then reduce the airflow to the prior setting. No, we never fire the stove hard for a little while. We could turn the converter off to do this. At this time, we can not fire the stove hard due to the fire risk. I have the liner installer coming out Thursday to inspect the problem and I'll have him sweep the chimney at that time. Although technique can have a serious impact on creosote buildup, I hope we can keep looking at the whole picture and try to find another cause. Please remember, this problem has occured with several different non catalytic stoves.

 

[Cord]

Wood at the worst case is damp, but not green. I will never burn green wood. In fact, I will run out of wood this season, even though I have 10 cord waiting to be split. That wood was first cut in late winter, so it is not ready. The chimney is a interior one. That said, the house is only a one story so half the chimney is outside of the home.

 

[HarryBack]

I am running a chimney roughly your size, or maybe bigger as it's an old coal chimney. If nothing else, mine over draws my furnace and I have to shut the chimney damper down to keep it from running away. .

Overdraws your furnace? How? Are they in the same flue, pray it isnt so?! Dont tell Elk!

 

[laynes69]

I have a wood furnace with a 8x11 masonary chimney and I have been burning about 2 months now and just got a few cups of stuff from the chimney. Before you go into burning hot fires, make sure your flue and chimney are cleaned. Once they are, get a small fire going, then build it up. Once the stoves up to temps, go ahead and load in some wood, but don't shut down the air. Keep the dampers open and watch the wood. When the wood is hot and starts to charr on the outer edges, go ahead and damper it down. Now watch your chimney and if your smoking like crazy, with the firebox isn't hot enough for the smoke to burn, or you don't have enough air going to the fire. The heat output and the chimney are a few places to look at. If your smoking like crazy, then you're not burning right. After the fire is going and you have loaded wood if the chimney looks okay, you should be good to go. If you can keep your firebox up to temps and burn cleanly, you may find you will burn less wood, getting more heat. Good Luck!

 

[Mo Heat]

A cat stove shouldn't produce very much creosote if the cat is 'lighting off' quickly each time you intiate a new fire. I am big on cat thermometers so you actually know what your cat is doing and are not just guessing, but I know these can be expensive in some cases (like with inserts). But what's $100 when you are on your 3rd or 4th stove!

I have some friends who have a big creosote problem similar to yours. When I visit I must be very careful not to get their stove as hot as I do my own or I'd easily start a massive chimney fire. They tend to burn very low, slow fires of short duration (2 - 4 hours) using mostly deadfall and poorly seasoned wood. They have a shortish chimney with a two foot horizontal (slightly inclined) run, which goes out a window (not good) and has no insulation (it's actually just black pipe -- also not good). They routinely have an inch or two of [fluffy] creosote stuck to the inside of the chimney waiting to burn their home to the ground. Luckily that has not yet happened, although I nearly managed to do just that one frightening visit.

The way I burn most of the time is to leave my primary air wide open and put just enough wood in there to do the job. This way I get a nice hot fire, but not too hot. Burn times are reduced and tending increased, but I get little or no creosote this way with little worry of over firing.

Your Catalyst -- If you are engaging your catalyst before an hour of good hot burning, preferrably allowing your first (reduced) load of wood to go to coals, then waiting for your second load to get rolling good (new wood charred and burning on all sides) then your cat may not be lighting off and may be fouled.

Do you have any pictures of your stove and chimney?

 

[Corie]

You shouldn't have creosote build ups like that if the cat is functioning correctly. There's just no way. Has the cat combustor ever been replaced? Have you ever pulled it to inspect its condition?

 

[Mo Heat]

... 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.

Corie, this was obviously easy to miss in the lengthy post, but he said he has changed out the combustor.

 

[budman]

... 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.

Corie, this was obviously easy to miss in the lengthy post, but he said he has changed out the combustor.

Oh s--T

 

[Cord]

Yea, it's easy to miss, but that was a really long post. If you read between the lines, you can see that I've tried to fix this before so I knew what questions would be asked. I want to get some pics, but it's dark out so you'll have to accept what you get.

 

[stoveguy2esw]

your lower chimney temperatures are the root cause, wet creosote can form very rapidly if chimney temps drop below 250 degrees. you may also be looking at an air leak into the flue liner ,this can cause temp drops as the air pulled in through the leak is not heated by the fire,cooling the flue into the "creosote zone" lol i hate that term. anyway , i'd have the liner checked out all the way down to the connection to the stove to ensure that its well sealed to the unit.

 

[Corie]

Sorry for my lack luster response. I thought I read it all, but I suppose I was a little too quick to poke at the fire.

Anywho, in that case I'm on the Mo Heat train. It seems you really need a cat combustor probe thermometer to moniter the temperature of the combustor and to be certain it is firing at all times. I wonder if you're letting the stove temperature get up high enough before engaging it?

Also, I don't think I saw you mention the strength of your draft at any point? Is it suck a lit piece of newspaper up the chimney strong?

I wonder if the chimney is being influenced by an exterior factor, like an overhanging tree? Or perhaps it doesn't adhere to the 2-3-10 rule?

I've managed to get more poorly designed stoves on worse sounding chimney systems to light the cat and burn smoke free; it seems, on paper at least, that your system should be providing good performance.

 

[elkimmeg]

I running my encore now first I can tell you you need to learn how to load it you are dampening off way too early clogging the cat and never getting it hot enough to dissipate heat in that chimney. I can't tell the times I have detailed how to run a secondary combustion / cat stove It never should be damped down till a real good bed of coal's exist the wood has char-ed and started second phase of the burning cycle and stove top temps are over 500 degrees. I never damper down too early fearing t I would get the same results you are
You got to build a fire and bed of coals.
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 proceedures, 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 effeciently that there would be little left for cresote to build up

 

[begreen]

Is it possible that the "really good draft" is being cooled by the barometric damper on illegally connected furnace to the same stack? Check the BD position before and then at the point when the stove is really cooking. I'm guessing it's pulling a lot of cool air from the basement.

 

[elkimmeg]

Eric I did not start it back up again you did .You admit to your less than code compliance illegal setup. Me, I would not broadcast as such,, time and time again

 

[elkimmeg]

Which code do you want me to cut and paste from the International Mechanical code or NFPA 211? Lets not hyjack the thread . I will post both codes tomorrow morning.
If you want I can also post the canadian code as well. Is 3 times enough? My point is not to brodacst the legality of your situation.
Remember I did not bring it up you did and harry picked you up on it not me

 

[berlin]

actually the main concern is that in the event of creosote buildup, there is no way to effectively shut down air to the chimney and that there will be air plentiful in O2 coming in through the unfired appliance (vs. O2 poor air that gets sucked through the fire in the woodburning appliance).

however having said that, the same installation has worked fine in thousands of homes; i have a gas water heater and furnace running in the same flue that i use for my coal stove, but as it's coal there is no creosote danger thus no chimney fire danger; the worry about co coming out of appliances connected higher or lower on a chimney that functions even decently is somewhat foolish, it wont happen; it is contrary to science unless were talking about power vented appliances in the mix.

 

[elkimmeg]

If your wood burning appliance is listed to be able to function in unison with the existing gas/ oil burner then that is an acceptable installation.
The next question is the Volgelzang listing? A Tramn was listed as such but contained a full listing approved by UL.

I mean pick your poison UN listed appliance using a shared flue. I do not care to hyjack the thread of get into this in depth


again it not up to me to decide, its up to your local authorities and they did approve it ?

 

[Eric Johnson]

berlin is right about not being able to control a chimney fire if you have two appliances hooked up to the same flue. Usually there's not a whole lot you can do if you have a chimney in a masonry flue, anyway. Just shut everything down and hope for the best.

My understanding about the danger of running a wood-burning appliance in combination with some other heat source in the same flue is that it's possible for your chimney to get so full of creosote that the gasses from the other appliance can't be exhausted anyplace other than the house. The way it was described to me is that you might have a creosote glaze that would start to popcorn up when the other appliance is running, so that even a chimney that appears relatively clean can clog up and poison your home.

All codes and other considerations aside, if you're aware of this potential and you only use the gas/oil furnace on rare occasions in the winter (say, when you go away for a few days), then just clean the chimney before you turn on the gas/oil burner. Ditto in the spring when you switch back to fossil fuels for the season.

The problem with out-of-code installations, as I understand it, is not that the cops are going to kick in your door in the middle of the night and haul you off to jail. More likely, if you have an insurance claim related to the hook-up (house burned down, furniture ruined by smoke, somebody dies) the insurance co. might decide that's the excuse they need to deny your claim, especially if you did the hookup yourself, or you were aware of the violation and maintained it anyway. Talking about it in a public forum probably wouldn't help your case in that event.

I don't think that's a hijack of this thread, because it sounds to me like maybe Cord is facing a similar dilemma.

 

[Cord]

Ok guys, I really need to get this thread back on track. I know how threads can wander, but I really need your help in trying to solve the problem. Here is a ground pic of my chimney. The brick is in excellent condition. The staining on the front of the brick is new this year. The staining on the flashing started to appear last year before we had the chimney relined. I hate the look of the new liner cap. It looks horrible up there. When I get a chance I'm going to get a new one to replace it. It's hard to see, but currently the openings in the cap are only 50% open. You can actually see the creosote trying to drip from the cap.

 

[Cord]

Ok, here is the existing installation. You can see the new work because it's a darker shade of black.

 

[Cord]

This is the adapter from the stove to the liner. The creosote started right at the cast iron stove adapter. By the back of the adapter the creosote was a good half inch thick. The creosote was loose and flaky. Things might have been worse, but the fire got into this adapter over the weekend which is why why shut the stove down.