Black stuff on chimney pipe & roof

[kieth4548]

Hello all, I just ran accross this forum looking for some answers and think this place is great. I am a new stove owner as of last Friday. I have an England 28-3500 which is attached to my furnace. I have to say this is a real nice unit. I have a question. I noticed the other day on my shingles that there is what looks like a shadow. I got on the roof and noticed it's some black stuff. I looked at my stove pipe cap and noticed there is a little bit of black sticky stuff on the edge of the cap. My question is what is it and why did it show up just after a few days of using the stove. I have spoken to a couple of people and they have told me this is normal. First I want to know if it is and am I doing something wrong. Is the stuff due to the pipe needs to be higher off the roof? I had the chimney put in by a contractor but it looks like I may need to rise it un another foot to get to the 2' rule. The chimney is about 2-3' from the peak of the roof.

Setup of my stove pipe & chimney. My stove is away from the chimney by about 6'. I have a 45 degree off the stove with a 38" vertical to another 45 degree going into a 24" horizontal going to a 90 into the chimney which is 16' tall. I get an excellent draft. I have had no problem with back puffing or fires. ALso my stove pipe is black double wall.

Sorry to make this so long but being a newbe have no one to ask.

Also I have read about using a thermometers to monitor the inside pipe temps???

Thanks for any help.
Kieth

 

[Moose]

Welcome to the forum kieth, the black stuff on your chimney is called creosote. Creosote formes on the inside of the chimney wall when the the hot gases condensate on the chimney then dries and forms a sticky tar substance (creosote). The sticky creosote will eventually dry and become brittle and flaky and some of it will fall off down the chimney. You will need to invest in a chimney bursh and regularly brush your chimney to keep the build up from getting out of hand. Too much creosote will restrict your chimney's ability to draft properly (smoke in your house) and pose a fire hazard. The creosote it self is flamable and if the fire is hot enough it can start a fire in your chimney which is not good at all, and I believe one of the main causes of house fires when heating with wood. If this happens you need to shut off all available oxygen to the stove and chimey by closing the air intake on the stove and if appicable closing the dampner in the black pipe. I like to install a dampner in my black pipe if there is not one for that reason you can pick them up for less than $10 and I just use it for that reason only. I have had a chimney fire once and it sounds like a wind tunnel in your chimney and your black pipe will glow bright red (mine was single wall) by shutting off all oxygen the fire went out promptly. You can lessen the amount of creosote build up by building only clean fires meand burning most of the fuel with as little smoke as possible and by burning only dry seasoned wood. the more moisture the more smoke/steam the more condensation you get. Also you need to keep your chimney temp up. by keeping your chimney temp up you don't give the gasses a chance to condensate on the cool chimney. As far as the height above your roof. As far as I know you need a minimum of 2' clearance above anything within a 10' radius of the chimney. Also I don't know if it is frowned apon or not but most chimney caps are covered by a wire mesh that is supposed to keep birds and what not out. Well I don't know of too many birds that fly down smoke filled pipes sticking out of one's roof so I remove the wire mesh when using my stove to keep the creosote from building up on the wire. I have had a wire mesh clog in about a week under the right conditions. Hope this helps. Not to technical savy so the number guys can chime in if you want numbers.

 

[kieth4548]

Thanks moose.. The wood that I am buring is well seasoned and dry. I was just shocked that it happened so fast (just a few days). I know that I will load the stove in the am and then set the dampers back so that there are red hot coals but very little flame. I then do the same thing when I go to bed. Is what im doing causing the problem? How do I keep the chimney temps up without buring a ton of wood. I notice that the pipes cools off very quickly when I set the dampers. Sorry about al the questions but trying to learn as I go.

Thanks

 

[Moose]

From my experience and If I understand you corectly. If you are puting wood on hot coals and shutting the dampner so that they don't actually burn but just smolder this will cause a large amount of creosote. The smoke that the wood is giving off is actually fuel and water. In a perfect world we would be able to extract every last bit of fuel from the wood and there would be no visible smoke just water vapors or steam. Wood stoves have come along way in the past few years and some especially gasification burners come extreamly close to extracting all the fuel from the smoke. So in a sence if you are allowing your wood to just smolder and smoke you maybe wasting valuable heat right out the chimney in unburnt fuel. I would recommend that find how your particular stove through trial and error likes to be loaded for the type of burn you are looking for, load it up and get a nice fire going. when the wood is burning well usually after 5-15 minuts you can throttle down the air to slow down the burn but you I think you will want to keep a fair amount of flame in your firebox so that your stove is burning efficiently ie cleanly. Some manufactures recommend that you burn the stove full boar with the door closed for a min of 15 mins aday to keep creosote levels down in the stove itself. If you have a glass door this can be a good indicating tool to see if you are burning cleanly. most of the time you can keep fairly clean glass for at least a week. if you glass is turning black and brown and or if your fire brick is turning black or borwn this would be a good indicator that you are not burning efficiently. You may not get the burn times between loading that you may have been hoping for but you will get a much cleaner burn and get the most out of wood that you paid or worked so hard for. BTW most of the claims by mfg's burn times are way out of proportion and are not real world.

 

[Moose]

Oh and I'm not sure about your double wall black pipe temps I just recently installed black wall on mine and I can touch it with my bare hand a good amount of the time. the plus side to this is it keeps the chimney temps up. I'm sure sombody will give you a ball park idea of what your black dbl wall pipe temp should be. and don't worry about the questions thats what we're here for to learn and to teach trust me I ask more than my fair share. And be patient wood burning is an art every stove every set up is different with different tendencies so keep plugging trial and error. Find out what works and what dosn't for your set up. I've been burning wood for 25+ yrs and I just moved and have two new wood stoves and I'm still learning their tendencies and I've been burning them since sept.

 

[Eric Johnson]

Welcome to Hearth.com and the Boiler Room, kieth.

Moose is giving you some good advice.

The only thing I would add is that creosote is a normal part of most wood burning, and it's going to show up first in the most visible places, which is to say the top of your chimney and the cap, if it has one. A small amount of creosote is not a problem. But if you start to get accumulations growing on the inside walls of your chimney, they could light off and cause a chimney fire, which is not a lot of fun. Like Moose says, get yourself some flexible rods and a chimney brush at a hardware store or one of the Big Box stores. It's not all that expensive. Then sweep your chimney and see how much creosote comes out. A couple of handfulls is no big deal. If you start filling up gallon buckets, on the other hand, then you'll have to figure out how to burn cleaner.

After that, check it periodically and try to keep tabs on how you're operating the stove (I assume it's a wood furnace) and try to compare the creosote formation with your burning habits and the weather. After a few of these exercises, you'll get a pretty good feel for what your stove is doing. Hopefully you have a cleanout tee or some other way to clean the chimney from inside, instead of having to climb up on the roof. If you can get a look up the chimney from inside, that will tell you a lot, especially when you know what to look for. A large accumulation of creosote in the cleanout tells you a lot about what's going on higher up. Wear safety glasses or learn to use a mirror to inspect the chimney from below.

Good luck!

 

[kieth4548]

I do let it come a good fire for about 5 -10 minutes unless it gets to be to big. After that I then back down the fire. So maybe I am backing the down the fire to much. I usually back it down to just a small flame. How much flame should there be to know that the fire is hot enough. Sorry to sound so ignorant. I have an england add on furnace 28-3500. http://www.englandsstoveworks.com/28-3500.html Should I put on a Thermometer to monitor the temps inside the black pipe?

thanks

 

[Eric Johnson]

We have a couple of Englander engineers who participate on this site, so hopefully they can give you some tips on getting a clean burn with that furnace.

From your description, I'm not convinced that you have a problem. As I said, creosote is a normal part of most woodburning, especially with older tech central heating appliances, because they are exempt from the EPA pollution regs. And smoke contains creosote, so the more smoke you let into the chimney, the greater the potential for creosote formation.

One thing my dad told me once is that "the creosote is supposed to wind up on your neighbor's car, not in your chimney." The point being that the hotter your fire and the hotter your chimney, the less opportunity there is for creosote to form, since it only accumulates when the temps cool down enough for it to condense on a solid surface. The problem with that approach, unfortunately, is that you're losing a lot of your heat up the chimney AND, you only want to very hot fire and chimney when it's clean, otherwise you could get a chimney fire, which will clean the chimney for you, if it doesn't burn down your house.

Anyway, don't panic. You need to find out how much creosote your furnace is producing before you can decide what, if anything, needs to be done about it. Check it out and tell us what you find.

 

[Moose]

How much flame, is kind of a hard question to answer with out being there and seeing how much flame you actually have. If someone knows what kind of pipe temps you should have then you could go get a little magnetic thermometer and stick it on the black pipe to monitor that temp. I got one for my last stove and it does kind of give you a better idea of what is going on with the different things you try. To start I would say get your fire going and set to where you think it should be when the fire is up and going there shouldn't be large amounts of smoke comming out of your chimney. I have a quadrafire 5700 and when it gets going there is basically no visible smoke but the stove is putting out massive amouts of heat. even with my 30 yr old fisher papa bear when it got going there was very little visible smoke. So use that as a guage. Now if you check and the chimney is smoking really good and you open your air alittle bit it will take a while for the fire to catch up and stabilize, so if you open it a little and run out to check the chimney it more than likley will still be smoking. If you have a fire going right now or will today I would recomend you open the vent wide open let the fire really get going for about 15 mins the stove should be designed to run like that. then after it is good and hot just back it down a little bit maybe between a quater and half. make sure you have the blower on to get the heat away from the fire box and I think this will clean the stove out real good I think when you do this and go out side the smoke will have the smell like coal this I believe is the creosote burning off. then on the next fire get it going good then back it off to a quarter to a half again and play with it a bit to find a happy median of wood consumption and heat out put. If I was to take a guess an over night or while you are at work burn would probably be arround 3/4 the way closed. There really is no majic answer put the dial on 2 then 3 times to the left and wala perfecto. but if definatly sounds to me like you have her throttled down way to much. you want to keep the fire brick clean little smoke as possible.

 

[kieth4548]

ok. thanks all.

I will try that tonight. I will see what it takes to get to the no smoke zone for say. Is there anything that I can put on my shingles to get the discoloration off? They are white so it's really shows.

I appreciate what everyone is doing. This is really a great forum for the newbee's

 

[Moose]

Well good luck with the white shingles : ) they do make a creosote remover, but my kids sprayed it all over the walls and well I guess I'll be painting in the spring. I don't know of any thing that would take the creosote off that wouldn't eat your shingles. if it is not the thick sticky stuff might try water, but I'm afraid that you might loose that battle with white.

 

[kieth4548]

LOL.. that's what my father-in-law said.. He said I shouldn't of gotten white shingles. As I told him when I built my house last year I didn't expect propane to go to $3.00 a gallon or I would have had all this installed when it was being built with black shingles... Again thanks for everything. Now i'm not as worried as before.

 

[kieth4548]

Do any of you guys know anything about those logs that you burn to help fight the creosote. I just talked to a person from northline express and he said that he personally uses a spray. He said that you build your fire, get it hot and spray in this stuff on the wood and the fire and it works on any built up creosote in the stove and chimney. Here's the link of what he said he uses. http://www.northlineexpress.com/itemdesc.asp?ic=5SA-2006.

 

[Moose]

Personally I've tried the logs and the powder stuff, but didn't notice a big difference. All I do is use the ole chimney brush and flex sticks every couple off weeks. I had to do the same thing when using the logs so I didn't bother. Cleaning the chimney only takes about 15 mins you just remove the pipe at the stove prob 3 screws and remove the cap prob 3 screws put a bucket under the pipe and brush. You can do it without going on the roof but you end up with alot of creosote on you. Then you screw everything back together and your done. you can get a brush for under 10 bucks and the flex pole is under 5 bucks a section I believer they are in like 4' sections so for a 20' chimney you probably need 5 or 6 one time investment peanuts when you consider the price of the stove and the amount of money you will be saving in propane.

 

[Moose]

kieth, quick question, You said you just built your house so I would assume that you are one of the lucky ones with a well insulated house. What part of the "USA" are you from? and are you trying to heat with wood totally or are you just subsitizing the propane furnace you already have?

 

[Moose]

kieth I was browsing the hearth room and stumbled upon a post I thought might interest you don't know how to link it so I just copied and pasted. Everyone has growing pains when switching to wood. enjoy.



This brings up a good point - liability to the manufacturer’s that DON’T specify operational temperatures in their owner’s manuals.

Vermont Castings covers their butt by saying: “Inspect the chimney and chimney connector at least twice monthly, and clean if necessary. When you first begin using the stove, check daily for creosote”

But seriously, how many of you clean twice a month? And check daily as a newbie? I wouldn’t have known what was excessive or what was normal. It took me months to learn how the stove was supposed to operate - and by far the BIGGEST problem was the lack of operational temperature guidance in my manual. I was dampering down to early and creating creosote. That was my first year burning a woodstove, I didn’t really know what to expect. I read the owner’s manual carefully, cover to cover, like 4 times. I followed every specification for clearances, r-values, etc - the total install was painstaking, but done right. All that is well and good, but I still didn’t know how high I was supposed to get the temperatures, or when I was supposed to damper down exactly, or what the temps were supposed to do AFTER dampering down.

After a few weeks of poor operation, I’m sure a bunch of creosote had formed. Soon after, I discovered that I was supposed to be burning much hotter than I had been, and that the stove worked much better when it was burned that way. I’m sure you can see the potential for problems when someone goes from not burning right to burning hot (and correctly). Needless to say, I did end up having a very minor chimney fire - I don’t remember a loud noise though, and it literally only lasted for a few seconds, there wasn’t even time to run outside and see what was coming out the stack - the only reason I know there was a fire is because smoke came out of several joints in the flue and the flue thermometer showed a spike in temperature (I forget how high it got, but I know it was NOT above 1200), and there was black debris outside all around the chimney (on the roof, on the deck, etc) like everything that was in there blew out all at once.

I could find no damage, I took the flue/chimney apart and saw no damage, but the last piece of the stainless steel chimney was discolored on the outside. I have heard that some people try to burn extremely hot every now and then to intentionally clean out their chimney this way, although that doesn’t sound like a great idea to me…

I have never had a problem since then, and when I clean the chimney only a couple handfuls of “black stuff” fall out.

 

[kieth4548]

thanks moose..that was a great find.. that is exactly the situation that I am in.. how hot is to hot and how cold is to cold. As per our conversation I am going to burn a little hotter. Hopefully I don't run into any problems.

As to your other question I live in Ohio and yes I installed a furnace add on due to the high propane prices. This is my main source of heat. I have my furnace set to be a back up if I don't get back and the temps drop to low in the house. Yes my house is very well insulated. There has been a few times that I had to open windows to cool the house down. My wood stove went out around 1:00 today and it's still 75 in here and the outside temp is 35.

 

[Moose]

Great love to hear about warm houses. Just left ohio lived up on the lake an boy did that wind suck the warm air right out of the house. if there was no wind I could easily accidently reach 90 degrees two rooms over but if it was windy I was struggling to get 65. went a little further north my first winter here.

 

[kieth4548]

Good luck to you in your new location. I too have had this house with some high temps. I haven't reached 90 yet but I have hit 85. I didn't even realize it was that hot. I knew it was hot but since it's a very dry heat you don't realize how hot it is at times. Again thanks for all the information you have given me today. I will let you know how things go over the next few days.

 

[kieth4548]

Ok.. i just started a fire. I did a hot fire with smaller pieccces of wood to get the temps up. All of a sudden I start hearing crakling noise in my black stove pipe that is coming right off the stove. Is that normal or do I have a problem. It seems that I read somewhere that that is normal that it's drying everything up.

 

[Moose]

what you are hearing is probably the glazed creosote drying up and starting to flake most of that will fall off and go up your flu. if the pipe was cold you might also be hearing the ting of the metal changing temps. as long as the pipe dosn't start glowing red and you don't hear what sounds like jet enging pumping in your pipe you should be good. and the noise should subside in a few mins.

 

[kieth4548]

ok... i let it go for a few but i got worried so I backed it down.. The pipe was hot so I know it wasn't the metal. I also heard it by the connection to the chimney pipe but not as loud. Should I bring the temps back up for a bit? I was worried that a fire might start. Also I have double wall black pipe so will I see it glow red?

 

[Moose]

If you are worried about starting a chimney fire by all means don't test your luck better safe than sorry. I would highly recommend a chimney brush a good sweep then try hotter burns. you don't have to run it full boar. if you just run it hot enough to keep good flame then the creosote should dry on its own. This will also make it much easier to sweep. that sticky stuff wont sweep real well.

 

[kieth4548]

Another ignorant question.. does creosote burn by actual flame contacting it or can heat alone start the creosote on fire. I just refired up the fire again and its hot but I hear no crackling noise. I know it's hot because I can barley keep my hand on the pipe.

 

[Moose]

I don't know the actual temp creosote with flame up but I do know when it does catch it burns hot as heck. when I have my under normal operating conditions I cannot hold my hand on my double wall black pipe either. I know earlier I said that you could touch it but that was in comparison to when I was running single wass black pipe I think the outside temp was betwee 2-400 degrees normal operating temp if I remember correctly no hand touching there. So the pipe should be hot and will burn you if you hold it there and I suppose if the stove was going full boar would most likley burn you. I will try to find that thermometer and let you know the temps I am running on my double wall pipe. I wont be home for a few days though