Greetings all. I finally got around to cleaning my chimmney, and I was shocked when I did. I have a 35 foot tall metalbestos chimmney. I was able to clean it from the inside with a brush and rods. When I did, I filled a 5 gallon pail about 3/4 full of black, shiney flakes. I wasn't able to clean the pipe that connects to my boiler due to it needing to be taken apart, but I am wondering if this is a disaster waiting to happen? My chimmney is now clean, but the pipe which connects my boiler to the chimmney is black stove pipe with a barometric damper on it. It is probably quite full of crap. If this were to ignite, would it just burn out with the clean chimmney, or could I have a serious problem? Is 5 gallons of this stuff excessive?
5 gallons of flaky black stuff
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Sounds like it is running too cool in the flue, though it could be the wood, or a combination of both. You might want to check the barometric damper to be sure it's not introducing too much air. By all means clean out that connector pipe too. This is a lot of creosote.
What is the wood like that you are burning? Is it well seasoned?
What is the wood like that you are burning? Is it well seasoned?
There are many forms of creosote. The most dangerous kind is the shiny black glaze that forms from burning a smoldering green wood fire. That will catch fire given a chance. The type your explaining is fairly harmless.
Wow , there is something funny going on with the stove or wood . Its hard to get a 5 gallon bucket of black stuff . I don't think Ive seen that much buildup over my life. Your wood could be bad , You mite have to add more air to the burn . You mite have started to build up slowly and cut off your draft, that would added to the build up and make it worse over time . Do you clean every year ? Do you have a hot water boiler with zone valves ? The steel pipe with in a few feet of the stove should not need to be cleaned because the stove should burn it off . I like to get my stove cooking every morning so it cleans the flue from the slow over night burn . If you have elbows you need to look for build up there . I don't know much about wood boilers but you mite have a problem with the damper
35 feet of is a fair amount of chimney. 3/4 of a bucket is not all that much. Is it possible the chimney has caught fire recently ?
This is why I hate the idea of a barometric damper. I mean we all try to keep all fresh air from infiltrating the pipe as it causes the pipe to cool to much and not be safe. Then along comes this "safety" item that is suppose to keep the pipe from getting to hot. I have a friend who lives where there are regulations and he has had nothing but trouble with it on his wood furness. This system does not sound too safe and I think the damper will exaggerate it. IMHO
I see that he has an oil/wood combo does the oil part need the barometric draft? Does this furnace use 1 flue pipe? Could the oil burner be running to rich adding more soot than normal to the chimney? Just questions that pop into my mind that I have no answers for myself.
If it were that much from an exterior masonry chimney...i'd be concerned. Being a metalbestos...i'd be way concerned.
When was it last cleaned???. How seasoned is your wood????. It's part of the learning curve, sounds like you are burning on the cold side/have wet wood but at least you know to clean it and get a cleaning regimine. Now you have a base point to judge from. If your wood isn't perfect, clean it monthly during this winter.
When was it last cleaned???. How seasoned is your wood????. It's part of the learning curve, sounds like you are burning on the cold side/have wet wood but at least you know to clean it and get a cleaning regimine. Now you have a base point to judge from. If your wood isn't perfect, clean it monthly during this winter.
Newmac_Owner said:
dull black dust is carbon, and relatively harmless, unless it builds up to ridiculous amounts and obstructs things.
shiny black is creosote and is a fuel for a fire waiting to happen.
something sounds out of whack on your wood, your air supply to the combustion, or a barometric damper that is not set right.
despite popular mythology to the contrary, barometric dampers have a legitimate and important role-- as long as they are set up and functioning correctly-- if they are not, then they can be a source of their own set of problems. but like so many other things, just because they can cause problems when set up wrong does not make a good case for saying that they're always bad. if we all proceeded that way, we'd have all rejected use of electric power because some improperly wired homes have burned down... master the technology- don't let the technology (or anyone's assumptions about it) master you...
Wow. Lots of questions. I'll try to address them all. I have a 35 foot Metalbestos chimmney. It is 8" in diameter. It is connected to the oil/wood boiler via a black stovepipe with an elbow and a barometric damper which is required for the oil burner. I burned oil all summer for my indirect DHWH. Since October, I have burned only wood. My system is a bit oversized, and idles quite a bit when the weather is mild. The entire system is only about 9 months old. My house was built last year. I did burn VERY wet, VERY green wood last year, but I have seasoned, dry wood this year. Most of the buildup was from last year as the house was being completed. I am rather unsure about the barometric damper thing. It seems to let a lot of cool air into the chimmney, but it is set per the manufacturer's specs. My system does have 4 zones including the DHW zone. I do not believe that there has been a fire in this chimmney. Which brings up another question. How dangerous is a chimmney fire in a metalbestos chimmney? What damage is likely to occur in a a fire in my chimmney? Would I have to replace the chimmney if I DID have a chimmney fire?? Also, does anyone have any idea how hot is too hot for a thermoometer reading on my flu pipe? I ask because I recently got it up to 600 degrees, and I was a bit nervous. It usually runs between 300 and 450. Sorry for the rambling, but I really am new to all of this.
Did you get the connector pipe cleaned out too? How did that look?
SuperVent pipe is rated UL 103-HT. The pipe is rated up to 2100 degrees, 1200 continuous. It can take brief exposures (10 minutes tested) to the highest temp. It will survive a chimney fire, but should be checked afterward. If there are multiple chimney fires, then the reason for the fires should be addressed and the pipe replaced. For your flue temps, are you giving surface temps or flue interior (probe) temps? 600 is fine for a probe temp. Actually, if you can achieve that once a day, that's good.
I'd clean it a bit more frequently until a pattern is established. If most of the crud was from last year's wet wood burning, it could be that is the last time you'll see this. Maybe clean again in February to see if things stay a lot cleaner with winter burning and dry wood.
SuperVent pipe is rated UL 103-HT. The pipe is rated up to 2100 degrees, 1200 continuous. It can take brief exposures (10 minutes tested) to the highest temp. It will survive a chimney fire, but should be checked afterward. If there are multiple chimney fires, then the reason for the fires should be addressed and the pipe replaced. For your flue temps, are you giving surface temps or flue interior (probe) temps? 600 is fine for a probe temp. Actually, if you can achieve that once a day, that's good.
I'd clean it a bit more frequently until a pattern is established. If most of the crud was from last year's wet wood burning, it could be that is the last time you'll see this. Maybe clean again in February to see if things stay a lot cleaner with winter burning and dry wood.
Temps of 600 purposely achieved on a daily basis can help eliminate creosote build up and with attentive maintenance you will learn the signs that tell you when it is time to clean your chimney. Do not think that just because you are using dry wood you will eliminate creosote. Learn the cleaning cycle. Any time your stack temp gets below 400-450 the inner surface if the chimney begins to become a collector plate for warmer smoke (condensate) which is actually creosote. I am not sure if you have a double wall or triple wall chimney but each layer of insulation your chimney has helps to maintain a temperature that is less prone to buildup. Your barometric damper, for the most part, will only let in cool air when there is more draft (neg. pressure) created by the warm chimney than positive pressure created by your wood stove (low/cool/fresh fire). Since the damper is required you have a potential persistent problem especially because you have idle times where the chimney can cool between heating surges. One of the main things to watch for is semi restricted air flow that can cause back pressures and allow the oil exhaust to vent into the home. One more reason to learn the cleaning cycle...Stay warm
Thank you for all of your replies. I still have not cleaned the elbow connector, and it will probably have to wait until spring because I need to shut down the system and allow it to cool in order to clean that section. I'm going to hope that it can wait until spring. My thermometer readings of 300-450 are taken at the elbow just before thr barometric damper. It is an external reading on a single wall black stove pipe. I was speaking to a firefighter that told me that the fact that all of the creosote brushed out of my chimmney easily was a good sign. I guess the really sticky stuff is much worse for fires. All of mine was a very dry, brittle, black shiny coal like substance. One pass with the brush cleared it all out quite well. I'm wondering if perhaps I have had a chimmney fire that I wasn't aware of?
Should only take a few mins to clean that section. Shut down the boiler, pull the pipe, take it outside. I used to have a woodfired boiler that was a friggin creosote still- if I banged on the connector pipe, you could hear chunks of creosote falling in.
A couple of questions- do you have a bypass valve on the return of the boiler? If cold water is returned to the boiler, it's my understanding that you will condense more creosote, and maybe cause corrosion. A termovar type valve will mix the return water with enough heated water to prevent this. I'm new at this, but its something to look into.
It sounds like a lot of creosote to me, but the admission of very green wood last year may account for it. best of luck
A couple of questions- do you have a bypass valve on the return of the boiler? If cold water is returned to the boiler, it's my understanding that you will condense more creosote, and maybe cause corrosion. A termovar type valve will mix the return water with enough heated water to prevent this. I'm new at this, but its something to look into.
It sounds like a lot of creosote to me, but the admission of very green wood last year may account for it. best of luck
Newmac_Owner,
I have a similar set up, 30 foot 8" chimney with the tee/cleanout plug in the basement. I have my oil boiler and wood stove connected to a 8"*6"*6" tee. from there one part of the tee goes to the oil boiler with a damper inline, the other side has 6" black pipe with one elbow going to the wood stove. I check the chimney ever 2 months in the heating season just because I too have that damper letting in cooler air. I usually only have to clean it once a year, but I check anyway. When I do clean it, I get about 2-3 gallons of cresote.
As for the 6" blck pipe and elbow, keep it clean. Just shut down the boiler and take the pipe outside and clean it out. Do it now, before it really gets cold out. If you don't, you could build up even more cresote and really reduce your draft to the point where you could be forced to clean it, probably on the coldest day of the year.
Don't worry so much about a fire hazzard, just inspect the chimney a couple times during the heating season and clean as needed. I love the metalbestos chimney, so easy to clean. Especially if you have the cleanout tee 5 feet above the floor so you can just take out the plug and look right up there.
I have a similar set up, 30 foot 8" chimney with the tee/cleanout plug in the basement. I have my oil boiler and wood stove connected to a 8"*6"*6" tee. from there one part of the tee goes to the oil boiler with a damper inline, the other side has 6" black pipe with one elbow going to the wood stove. I check the chimney ever 2 months in the heating season just because I too have that damper letting in cooler air. I usually only have to clean it once a year, but I check anyway. When I do clean it, I get about 2-3 gallons of cresote.
As for the 6" blck pipe and elbow, keep it clean. Just shut down the boiler and take the pipe outside and clean it out. Do it now, before it really gets cold out. If you don't, you could build up even more cresote and really reduce your draft to the point where you could be forced to clean it, probably on the coldest day of the year.
Don't worry so much about a fire hazzard, just inspect the chimney a couple times during the heating season and clean as needed. I love the metalbestos chimney, so easy to clean. Especially if you have the cleanout tee 5 feet above the floor so you can just take out the plug and look right up there.
like brother bart said" what little i new about"...... do not wait till spring. shut the fire down and clean the pipe. i do not know your set up but the pipe is closer to the flame. peace and be save
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