Creosote problem in stovepipe

[Wlmedley]

I have been using the same stove and stovepipe for the last 35 years.Stove is the biggest Buckstove that was available in 1987 and is inserted in my fireplace.I have 8" stainless steel single wall pipe  from stove to approximately 1' out of flue tile.My problem is after about 2 months of burning I have to get out a 30' ladder and clean pipe which is dead of winter.It is only the last 2 or 3 feet of pipe that gets stopped up which I presume is because pipe is cold.This used to not bother me to bad but anymore I hate to climb up there especially in January.Anyone have any ideas that would at least get me through a complete winter before I have to clean it.Also I burn all hardwood,mostly white oak, and keep at least two years ahead so it's pretty dry.

 

[Old Greenhorn]

That's a lot of chimney. Do you know if the stove outlet is 6" or 8"? If it's 8" you pretty much have to stick with that on the pipe size. If it's 6" and you have an adaptor, you could perhaps change to a 6" pipe or flex liner.
I think my chimney is just a tad shorter with a 6" liner and I get a coffee can of junk out after a full season of burning full time.
Also, it depends on how your stove is designed. As much as I hate the EPA changes to the stoves, the newer ones after their mandates burn a heck of a lot cleaner with those secondary burners in them to wring the creosote out of the smoke and they also provide more heat with that burn.
I hated (really hated) buying an EPA stove, ($$$) but when I got it, my life got a whole lot easier and warmer.

[Wlmedley]

I put the stove in when I built my house.I hired a brick layer to build the chimney and had the stove there so he could figure out how firebox should be made as I never plan to use it without a stove,so he didn't have to make a draw chamber or damper.The smoke outlet on stove is actually a rectangle which if it was used as a freestanding stove you had to buy a adapter from Buckstove which went to 8"pipe.I made my own to get it to work in fireplace.I spent about 500$ a few years ago replacing fan and motor and thermostat and building a new adapter which was rusted out.I probably should have bought a new stove then because like you said the newer ones probably are more efficient but they are about $2500 :'(

[Don P]

Other than using insulated pipe, the hotter you can run it the better the chances of keeping the flue temp above the sticky point. 

[beenthere]

Insulated pipe is about the only "fix" available. The entire chimney on three sides is exposed to the cold winter temps and the single wall pipe doesn't keep the combustion gases from cooling before they turn to chimney-blocking creosote. Not good news for you.

[SwampDonkey]

I would have to agree with Don and beenthere. When I built 4 years ago, I made sure the flu was up through the centre of the house using closet space. Also I have floor clearance so I can brush from the basement floor. You've got a cold chimney for sure, thus your troubles.

[mike dee]

Get a thermometer to monitor your woodstove flue gas temps. Do not use wet wood. 

You need to run your fires hot for the first few hours before closing the dampers. Cold chimneys and low smouldering fires are your problem if you are only using dry seasoned oak as your fuel.

[ButchC]

I have a very similar set up, a huge fireplace in the kitchen with a 6" liner in a brick chimney outside the house. Very little liner sticks out the top of the brick chimney, just enough to install a cap. I have a Jotel CB Rockland insert which is an EPA stove with secondary air.  Just cleaned my chimney and got a couple handfuls, about normal for a seasons worth. I do have an issue with the spark arrestor cap plugging up the screens. Usually twice a season I have to get the ladder out and take a stick with me to tap the screen to clean it off. I wait for nice days to do it. You might try insulating what sticks out of the masonry chimney, that should help a bit, and build smaller, hotter fires if you can. I ran several air tight stoves like yours and no matter how dry the wood was cleaning the chimney was needed a few times over the winter, sorry I have no other suggestions for you.

[peakbagger]

Exterior chimneys are tough compared to an interior chimney especially uninsulated. Most folks want the fabled "overnight burn" and that is an invitation to creosote buildup no matter how well seasoned the wood is. The standard overnight burn method is get a good hot fire going, they load in huge chunks of wood before bed and cranking the air supply down to keep it idling all night so it does not have to be lit again in the morning. The problem with that approach is that there is not enough air for complete combustion with the air cranked down. That leads to a smouldering fire that is not burning fully. A big chunk of the BTUs are going up the stack as carbon monoxide. Unless it's a catalyst equipped unit, the internal combustion temp is just not high enough to fully burn the CO. Various volatiles get released and then condense out on the walls of the chimney as the gases cool down. Many folks have oversized stoves and that makes it even worse. Ideally folks heating with wood should have two stoves, a smaller one for spring and fall and larger one for winter. Few people are willing to go to the hassle, so they get a big stove and go for long burn times. Ideally if you do need to use a big stove it should be used for short burns and small loads burned hot. 

Modern EPA compliant stoves are built to burn cleaner and more efficiently but the trade off is they are less flexible with far lower turndown. The catalytic equipped stoves have bit more turndown but compared to an older "smoke dragon" they still are fussy compared to the older units. The non cat units are even fussier with lower turndown. In many cases the EPA stoves have hidden air ports or stops in the air ports so that the air can not get turned down, that means they will burn hot even when the owner wants them to idle. 

One hint that may help is split your wood smaller, that usually leads to hotter burn but the tradeoff is shorter burn times. Combine that with using a stack temp gage to maintain a hot burn temp with smaller loads will really help. You may reduce your wood usage byt 10 to 20% by burning clean. Given where you are plugging going with an insulated stack may not help effiiency but it may keep things from condensing in the stack and letting them pump out into the neighborhood. 



       

[Old Greenhorn]

.... In many cases the EPA stoves have hidden air ports or stops in the air ports so that the air can not get turned down, that means they will burn hot even when the owner wants them to idle. ....
     

And THAT right there is my complaint with these stoves. I see this as very dangerous. As a firefighter who has dealt with many chimney fires we found that choking off the fire was the first step toward saving the house. 
 I have had a few go off in my stoves over the decades but always caught them, choked it off and all was good. You can't do that now and I will never get used to it. OTOH they do burn cleaner and this reduces the chance of build up in the chimney, but this is a decision I would reserve for myself, not some environmental engineer who decides the clean air is more important than my house.
 On those cat stoves, the cat wont work until you get it hot enough to get the cat working, so in a choked down fire, the cat does nothing. It takes a fair amount of heat to get that cat burning, and when it does you get a lot more heat out of the stove. Downside is they are fragile and replacement is expensive at about 200 bucks a pop. I've blown out 2 in 3 years and I think I am done with that. New stove on order for the shop.

[ButchC]

In many cases the EPA stoves have hidden air ports or stops in the air ports so that the air can not get turned down, that means they will burn hot even when the owner wants them to idle.




     

I would say in all cases, at least in non-Cat types. 6 years ago when we purchased the Jotel Rockland it sat in the garage for a while before it was installed and being the curious type I tried to figure out what made it epa approved and the only two things I could find was secondary air and a stop in the draft adjustment that preventeed it from being closed. 
Adjusting the feeding to keep it from running us out of the kitchen took a while but once done I really like it and I surely don't miss cleaning tbe chimney 2-3 times a year!! 

[Wlmedley]

I usually start burning around November 1 and my problem here is the weather fluctuations.It might be blue cold for awhile and then warm up.I usually don't let stove go completely out and it will hold a fire a long time.I thought about putting a insulated pipe in for the last section as it is the one that stops up the worst.The older I get it becomes more dangerous to climb up there and clean it.It has been a good stove heating whole house unless temperature drops below approximately 10F but maybe I should replace it.Afraid I might still have same problem.

[Hilltop366]

Not a fix to the creosote problem but a possible fix for climbing a ladder.

There use to be a company that sold a kit to install in your chimney that used a chimney brush a couple of pulleys a hand a hand crank and some cable so you could brush your chimney from the ground. One pulley on top one below the stove pipe with the crank on a shaft running through the chimney so when you turn the crank one way it shuttles the brush up the chimney turn the other way to bring the brush back down.

[Hilltop366]

Not the brand I was thinking of but the same thing, or as we often say "the same thing only different".



http://www.swiftchimneycleaner.com

[doc henderson]

I run the double wall insulated.  it is always the cool spots that condense the gas into liquid and it dehydrated on the surface and buils up over time.  incomplete combustion and that is why these products remain flammable.  If there is a cap to remove, and you can get to the small square flue, pack rock wool around and further down that the trouble spot to insulate it.  if the gas maintains more of the heat, then the combustible stuff goes out the chimney.  I have a birds guard 1/2 in wire on mine, and that is what I have to clean on my shop.  the draft on the house has always been better.  i clean it once a year, but it really does not need it.  a good hot fire now and then will help as well.  

[doc henderson]

plan B.  hire a professional to do the cleaning in January.  It is not a bad idea to have someone inspect the system occasionally.  we had some internal air duct that had cracks, and I could not shut the stove down as tight.  he told us about some stove putty and it has been fine for 5 years since.  too hot a fire occasionally, but not too hot.

[Wlmedley]

For years I didn't use a screen on top at all and it is the first thing to get stopped up but I can see it from the ground and pipe needs cleaned by the time it gets clogged anyway.I did a little research on a new Buckstove and they now use a 6" pipe so if I replaced stove I would have to replace pipe also I guess.Runs into a lot of money and not sure if results would be any better than what I have.New stove is EPA compliant and I think qualifies for a tax credit.My house is all electric and electric savings would probably pay for stove in a few years plus every time we have a storm or extreme cold spell the power goes off so I have to have a back up.Just wondering if I could replace my 8" single wall pipe with 6" double wall and see if that would solve my problem.If not I could get new style stove and already have pipe I place.

[doc henderson]

i understand it is the drop in temp and condensation that builds up.  I run double wall in the house to the ceiling for that reason. so it may solve the issue.  the new stoves are more efficient.  Mine is 85% rated I think.  the new pipe should help.  not all newer stoves burn as pretty, but we are happy with ours.  Alvarez

[beenthere]

For years I didn't use a screen on top at all and it is the first thing to get stopped up but I can see it from the ground and pipe needs cleaned by the time it gets clogged anyway. I did a little research on a new Buckstove and they now use a 6" pipe so if I replaced stove I would have to replace pipe also I guess. Runs into a lot of money and not sure if results would be any better than what I have. New stove is EPA compliant and I think qualifies for a tax credit. My house is all electric and electric savings would probably pay for stove in a few years plus every time we have a storm or extreme cold spell the power goes off so I have to have a back up. Just wondering if I could replace my 8" single wall pipe with 6" double wall and see if that would solve my problem. If not I could get new style stove and already have pipe I place.

Yes to running 6" double wall in place of the 8" single wall. Maybe a 6" flexible stainless steel liner would slide within the 8" single wall and function like a double wall. Worth a shot to save some money. 

Example of size outside diam of 6" double wall in this link.

6 Double Wall Stove Pipe - Duravent Stove Pipe | Woodstove Outlet

[Hilltop366]

I would check around to see if it is allowed to drop two sizes in chimney from the flue size, some say the chimney should be the same or larger than the appliance. I think I have heard the dropping one size is ok by a stove guy but I would not put money on that, it may be different in your area. Worth checking out before putting down money on a new chimney liner.

[Don P]

It would certainly void your insurance, NFPA allows a increase but never a decrease from appliance outlet size. Another thing that comes to mind with double wall is all the ones I know of require a 2" airspace around the pipe, it is not allowed to be filled with insulation, brick, flue liner, or anything other than air. Check the manufacturer directions for that if you do go that route, one of the chimney reline kits might be the direction.

[Wlmedley]

I'm pretty sure clay flue is 12".I have a cover on top of clay flue with a 8" hole to keep most of the water out and to center pipe.I don't know if smaller pipe would draw properly. I think I could fit double wall 8" in clay flue.By looking at link Beenthere posted it's only 11/8" bigger.If that's the case I'm sure it would fit.If I went with new stove later hopefully larger pipe than what is recommended wouldn't hurt.Don't know why Buckstove is now calling for smaller pipe on new stove which is approximately the same size as my old one.

[Wlmedley]

This is the stove I have now. I don't know how good the new ones are but this one has served me well.It has only been pulled out once in 35years.It burns mostly continuously 5 months out of a year. I may be wrong but if something holds up good I like to replace it with the same brand.If I can get creosote problems resolved a little I would like to keep using it.

 

[Don P]

I don't believe that link is chimney pipe, I think that is connector, like from a stove to the chimney.

[beenthere]

This is the stove I have now. I don't know how good the new ones are but this one has served me well.It has only been pulled out once in 35years.It burns mostly continuously 5 months out of a year. I may be wrong but if something holds up good I like to replace it with the same brand.If I can get creosote problems resolved a little I would like to keep using it.

Saying the single wall pipe has been in the chimney for 35 years? 
Is it stainless steel? 
As mentioned, just hire the chimney cleaning work done and save getting on a roof/ladder.