Draft/Creosote Question

[Apiator]

My uncle (in Georgia) has a Buck 91 (Cat Insert) in his house which is about 1500 sq. ft. It is installed in a masonry fireplace with conventional masonry flue...approximately 15' high chimney.

He and my aunt continue to fight the creosote buildup on the glass. After speaking with them, I don't think they're burning anywhere near hot enough, and subsequently leaving tons of creosote. The wood they're burning is seasoned oak.

They say they occasionally see temps around 500º. I believe it should be closer to 1400º with the catalytic combuster. They also mentioned that there is no starter pipe from the stove going up the flue. My aunt thinks there is a draft problem. Could this be the cause? Poor draft=low temps & poor performance=tons of creosote??...

I have an Avalon Olympic insert (in Mississippi), and installed my liner all the way to the top of my chimney. I get great draft, and the soot on my glass just wipes right off.

Opinions/Recommendations?

Thanks

 

[Apiator]

Also....How far should a starter pipe go up into the flue?

 

[LLigetfa]

Starter pipe? I think you answered your own question, namely that a liner should go the full height of the tile flue.

 

[Apiator]

Starter pipe? I think you answered your own question, namely that a liner should go the full height of the tile flue.

Looking at the owner's manual on the Buck Stove website, it gives 3 masonry chimney options:
1. A starter pipe going what looks like 18" or so up into the flue
2. Same arrangement with a block off plate
3. A Liner going the entire length of the chimney.

 

[LLigetfa]

Ah yes, but does it say any of those would guarantee a good draft on a 15’ high masonry chimney? I forgot to ask, is it an inside central chimney or external?

 

[tcassavaugh]

long ago, i had a buck insert in my fireplace with a flexable connector to the stove and a flu block off plate that went.....about 4 feet up the chimney. it was oblong and alot like the muffler pipe you can buy. After my third chimney fire, primarily at the flue, i relined the whole chimney used it a year with no problem and sold the house. I drive by it frequently and its still standing so, i guess the installation was ok. I'd recommend going the full length of the chimney even though the book gives you options.

Also, there are two different temps. one of the stove or pipe which should remain under 750 or so...often recommend 500-600 in here, and the temp of the cat. If i remember right, it lights off around 500 degrees and will go to about 1800. It was marked for a safe range of about 500-1500 or so if i recall correctly. I could be off a couple of hundered at the top end so don't quote me. So, if your they are burning the stove around 500, its pretty close but if the cat thermometer is at that range, they could burn it a little hotter. That said, i never could keep my VC glass clean. it was always dirty...i'd just give up and let it burn off.

hago

cass

 

[LLigetfa]

Manuals are written by people that want to sell stoves. If they had to print worst case warnings on them like on cigarette packages, they wouldn't sell. Some people will try to hang on the written word to justify taking shortcuts and then when it bites them, they think they can get off on a technicality. It might work for beating speeding tickets but with wood burning, you cannot beat the laws of physics on a technicality.

 

[Apiator]

Ah yes, but does it say any of those would guarantee a good draft on a 15’ high masonry chimney? I forgot to ask, is it an inside central chimney or external?

Chimney is on a wall that opposes the carport....open on one end. I guess that qualifies as quasi internal.

$$$ is definitely an issue with them. That being said...What are current recommendations for approx 16' of flexible liner? My liner is Magnaflex or Duraflex I believe...can't remember. Of course, I insulated mine, and installed a block off plate. Overkill to be sure. They will not be able to do all that.

I think I will encourage them to get a full length stainless liner with top cap if possible. They'll be lucky if they can do that. If that's not an option, is a 4' starter pipe up into the flue NOT a good idea?

 

[begreen]

With a short flue, a full liner is going to give the best bang for the Buck. The chimney should be thoroughly cleaned before proceeding. Running the stove as a slammer is not up to code and probably is contributing to the poor performance. From the description, if the carport is not enclosed, it sounds like an exterior chimney. If the chimney is in good shape and has a moderately sized tile liner, then a stub, with a damper block-off plate could help. A stubbed install would be a bad idea if a) the chimney has no tile liner b) the chimney has a tile liner that is in bad shape or c) the chimney has a tile liner that is very large. We need the chimney throat dimensions to determine whether this is the case or not.

The anemic burning could also be a symptom of wood is not fully seasoned. Oak needs a couple years to dry out after it's been split. Resplit some of their wood and check the fresh face of the wood for dampness by pressing it against your face. If it feels cool and damp, that is part of the problem. Or it could be the cat is plugged, contaminated or just shot. How old is the stove?

 

[Apiator]

How old is the stove?

Stove is 4-5 years old. I think they're burning wood that has seasoned about 1 year. Not perfect, but better than completely green. Heck..the oak I'm burning is about 10 months old, and I have no problem getting a lovely secondary burn and 500º with my stove top thermometer. They have the cat combuster thermometer and it should be reaching 1200º or so, and they're barely seeing 500º.

Their problem is probably muti-faceted, but I have little doubt that their flue/lack of liner set up is a huge contributor. If they've been burning like this 4 years, then I suppose it's possible that the combuster is clogged. I'll see if they can do a good inspection, although I have my reservations.

 

[Backwoods Savage]

My uncle (in Georgia) has a Buck 91 (Cat Insert) in his house which is about 1500 sq. ft. It is installed in a masonry fireplace with conventional masonry flue...approximately 15' high chimney.

He and my aunt continue to fight the creosote buildup on the glass. After speaking with them, I don't think they're burning anywhere near hot enough, and subsequently leaving tons of creosote. The wood they're burning is seasoned oak.

They say they occasionally see temps around 500º. I believe it should be closer to 1400º with the catalytic combuster. They also mentioned that there is no starter pipe from the stove going up the flue. My aunt thinks there is a draft problem. Could this be the cause? Poor draft=low temps & poor performance=tons of creosote??...

I have an Avalon Olympic insert (in Mississippi), and installed my liner all the way to the top of my chimney. I get great draft, and the soot on my glass just wipes right off.

Opinions/Recommendations?

Thanks

See above in bold. That is probably the best answer to their question. What exactly do they qualify as seasoned oak? Most folks will just say they have good seasoned wood. Either someone (probably a wood seller) has told them that or they think because Grandpa used to burn oak the same year it was cut. That will not work in today's stoves.....and rightly so. It should not have been good practice even for Grandpa but he know no different.

Around these parts we will not attempt to burn oak until it has been cut, split and stacked out in the wind for 3 years. So check with them to find out what their version of "seasoned oak" is. Tons of creosote says the wood is not ready to burn!

 

[oldspark]

Too many varibles to put time frames on drying wood, my 3 year old oak does not burn any better than my year old stuff, why because it was dead on the ground when I cut it, varibles varibles varibles when will we learn, another reason to own a mm.

 

[firefighterjake]

Could be a draft issue . . . could be a wood issue . . . or it could be an air management issue.