Creosote Buildup

[mattd860]

I've been running my Harman SF-160 wood boiler for about 4 years now and every year I have a lot of creosote buildup. This year I have insulated my garage where the boiler is located but now the creosote buildup has increased and the odor which used to escape from the eave vents has no where to go but into my house!! I am burning very dry wood that is covered and stacked so it's a dry as can be for eastern Connecticut.

The buildup is so bad that it leaks out of the chimney over night when I turn the thermostats down which idles the boiler for most of the night. I woke up this morning to a pool of liquid creosote underneath the stove pipe and streaming to the middle of my garage floor. Yuk!! Worst of all my wife equate the creosote smell to cigarette smoke so now she's not happy. The garage insulation has greatly improved the efficiency of my stove since heat loss is contained rather then venting to the atmosphere but now I have to deal with this smelly problem.

My stove has a 6" flue diameter. I run about 5 feet of single walled pipe out of the back of the stove and up to the ceiling where it becomes double walled pipe for another 10 feet (so 15 feet of pipe total). The single wall elbow coming out of the back of the stove and the 5 feet of singled walled pipe have to be changed every year because the creosote rots them completely. The double walled pipe is still in great shape and never builds up any creosote at all except at the chimney cap.

Is there anything I can do about this? I'm well aware of the flammability issue with creosote and the hazards associated with that but I also need to deal with that smell too so now it's A1 priority to reduce it. Do they make double walled stove pipe for the interior or stove pipe that is better sealed so the creosote doesn't leak out everywhere? If I can keep it contained in the stove and chimney I think I can reduce the smell considerably.

Take a look at these photos of the stove prior to me insulating the garage. You can see the creosote weeping out of the pipe. Since this picture, I now use one single 5ft section of pipe and a 90 degree elbow. I have tried both galvanized and black piping.

Thanks.

 

[Eric Johnson]

Replacing the single-wall with insulated pipe might solve your problem, since creosote condenses out of the smoke when it cools prematurely (i.e., before it gets into the insulated chimney). Insulated pipe should keep it hot enough to avoid that.

You may have a partial blockage in the pipe or further up the chimney, causing the smoke to linger longer in the single-wall section of pipe, increasing the amount of creosote condensation compared to what you experienced before. On the other hand, insulating the garage should have helped the problem instead of making it worse. I'd inspect the pipe and chimney before doing anything else. If they're both relatively clear, I'd consider investing in some double-walled insulated pipe.

Maybe somebody else has a better idea. That's just my take on it, for what it's worth.

 

[98kx1927]

It is the idling that causes the creosote build up. The only way to "eliminate" it is to burn dry wood, and don't allow the boiler to idle. You state you burn dry wood already so you need to focus on how to keep the boiler from idling.

1. add storage, this is the best way.
2. control your loading of the boiler better, more frequent smaller loads can help.

You can search on the forums and you can see this question asked/answered many times.

david

 

[mike van]

Matt - If you search Harman on this forum, you can read some of the issues I went through with my SF260 for 16 years. If you can burn coal for a week or so, it will dry up / make flakey some of that creosote. Mine never did good on coal, not enough draft I think. I'm surprised yours builds in that metal pipe, mine was the worst in the masonry flue. My chimney had that hard glassey creosote in it, the kind you can't chip out with a screwdriver. Sometimes I could barley pull an 8" brush down that 8" pipe. I do not miss that job, and I would do it every few weeks.

 

[F4jock]

98 hit the nail on the head. Burned wood long ago. Creosote and the associated maintenance is why I went over to pellets despite ten acres of free wood out back.

 

[mattd860]

I guess I just really need better stove pipe to prevent the creosote 'stench' from venting into the garage or dripping onto the floor. Are the joints in the double walled stove pipe sealed differently than the single walled? Is there such thing as an elbow that can't be adjusted and therefore has NO joints that can weep air or creosote??

 

[bholler]

I guess I just really need better stove pipe to prevent the creosote 'stench' from venting into the garage or dripping onto the floor. Are the joints in the double walled stove pipe sealed differently than the single walled? Is there such thing as an elbow that can't be adjusted and therefore has NO joints that can weep air or creosote??

What direction are the joints in your pipe running the top pipe should always go into the bottom one that will help with the leaking but that wont fix your problem. To fix the problem you need to change your burning practices or setup like 98 said

 

[maple1]

Could try not turning your stats down at night.

And/or not loading so full at night.

Plus also sounds like your pipe is assembled backwards like the last post mentioned.

 

[mattd860]

Yeah pipe is backwards. But it also leaks out of the many joints in the elbow as well. My local fireplace store suggested putting hi-heat RTV along the joints of the eblow.

 

[bholler]

My local fireplace store suggested putting hi-heat RTV along the joints of the eblow

That wont work rtv wont hold up to the heat. And yes there are several types of fixed elbows. But again none of that will actually fix the problem it will only make it not as visible

 

[GENECOP]

Don't know if it's been mentioned, but I use two scoops every other day of Rutland Creosote Treatment....it will not solve the problem of why the creosote is being formed, but cleaning is much easier all around...Heat Exchangers, chimneys, elbows.....just a loose powdery coating blows right off all surfaces.....

 

[woodsmaster]

Don't load it as full. Add storage. Problem solved.

Edit : sorry for being so vague. The key is to avoid idling. Less wood, storage or more heat load is the only way I know to do that. Installing the pipe so creosote drips back into boiler will help some but it will still stink and probably increase your chance of a chimney fire.

 

[mattd860]

But, but, but if I don't load it as full then it won't last all night long....

I'm interested in learning more about storage so I'm going to start doing some research.

 

[JrCRXHF]

I have the same boiler. I run Insulated pipe and do not have any creosote build up in the exhaust pipe at all besides a little on the bottom of the chimney cap. I also turn my heat off in my house during the day and then build a fire when i get home and run the system hard all night. I also don't use it on warmer days i use my NG Triangle tube boiler. The big problem is idle time with the boiler it does not do well at all with idle time and with exhaust temps lower then 350-400F

 

[shizzu]

I'd be curious to know how dry your wood is, do you have access to a Mc meter? Is the wood split? Build smaller hotter fires, if you're still getting creosote with the smaller hotter fires I would say wet wood. But what do I know, I've only burnt Alaska wood and pine never wood in your area, it may do things I am unfamiliar with.

 

[mattd860]

Wood is split. Smaller fires means I have to load more often

Alaska might be dry but out here in Connecticut we have millions of little minions that run around at night with backback sprayers soaking everything in sight. This typically leaves everything everything on the ground wet and many foggy mornings.

 

[Block Inlay]

It is the idling that causes the creosote build up. The only way to "eliminate" it is to burn dry wood, and don't allow the boiler to idle. You state you burn dry wood already so you need to focus on how to keep the boiler from idling.

1. add storage, this is the best way.
2. control your loading of the boiler better, more frequent smaller loads can help.

You can search on the forums and you can see this question asked/answered many times.

david

Could I hijack this thread a little and ask a few rookie questions? I tried a search of this forum but didn't find quite what I was looking for.

Does "idling" refer to damping down the boiler so it burns slowly for a long period of time? I see the value in burning smaller, more frequent loads of wood...but this is tough over night or when nobody is home during the work day. If anyone could help me out with some links on this subject, I'd really appreciate it.

 

[bholler]

Alaska might be dry but out here in Connecticut we have millions of little minions that run around at night with backback sprayers soaking everything in sight. This typically leaves everything everything on the ground wet and many foggy mornings.

That is why your wood should be off the ground and top covered