Cunningham wood stove, any advice on secondary burn?

[EJJohnson]

Hello, new member here. Last fall I got a Cunningham 203 wood stove and installed it in the basement.
Well the stove really impressed me, I have a 2500 sf 1850s house with scattered insulation, plaster and lathes,
well there is plenty of ventilation. Anyway I was able to keep the house warm (low 60's) down to outdoor temps around 25F. One question I do have is how do I know when the secondary burn chamber is lit off. I was burning petrified wood (5-6 years old) last year, I will have newer seasoned wood this year. The stove shares the class A chimney with the oil hot air furnace (legal in Maine) which was built in the late 80's, and is about 43 ft tall. When I cleaned the chimney with a rotary cleaner I got about a gallon of creosote, but that was with the super old dry wood. Where should I keep my stack temp at? I know this is a older stove design, but I would like to get the most out of it. By the way I try not to burn the oil furnace, I only burnt about 30 gallons of heating oil last year (3-4 cord wood, 4 1/2 ton pellets in the US Stove 8500 on a different chimney). Any and all advice would be appreciated, thanks.

 

[bholler]

Hello, new member here. Last fall I got a Cunningham 203 wood stove and installed it in the basement.
Well the stove really impressed me, I have a 2500 sf 1850s house with scattered insulation, plaster and lathes,
well there is plenty of ventilation. Anyway I was able to keep the house warm (low 60's) down to outdoor temps around 25F. One question I do have is how do I know when the secondary burn chamber is lit off. I was burning petrified wood (5-6 years old) last year, I will have newer seasoned wood this year. The stove shares the class A chimney with the oil hot air furnace (legal in Maine) which was built in the late 80's, and is about 43 ft tall. When I cleaned the chimney with a rotary cleaner I got about a gallon of creosote, but that was with the super old dry wood. Where should I keep my stack temp at? I know this is a older stove design, but I would like to get the most out of it. By the way I try not to burn the oil furnace, I only burnt about 30 gallons of heating oil last year (3-4 cord wood, 4 1/2 ton pellets in the US Stove 8500 on a different chimney). Any and all advice would be appreciated, thanks.

Well first off who told you a shared chimney was legal in Maine? It simply isn't true. And even if it was that doesn't change the fact that doing so will make the performance of your wood stove suffer greatly due to the air that can flow through the furnace diluting the wood stove exhaust.

As far as stack temps you typically should run it up to 400 or so then shut back to 250 or so. It is hard to give you much advice because the oil furnace in the chimney will mess everything up.

 

[barnaclebob]

Well first off who told you a shared chimney was legal in Maine? It simply isn't true. And even if it was that doesn't change the fact that doing so will make the performance of your wood stove suffer greatly due to the air that can flow through the furnace diluting the wood stove exhaust.

As far as stack temps you typically should run it up to 400 or so then shut back to 250 or so. It is hard to give you much advice because the oil furnace in the chimney will mess everything up.

Unless he means one chimney with separate flues for the wood stove and furnace?

 

[bholler]

Unless he means one chimney with separate flues for the wood stove and furnace?

I guess he could be saying that. If that is the case then yes that is absolutely fine. But from the wording I didn't think that was the case.

 

[begreen]

Well first off who told you a shared chimney was legal in Maine? It simply isn't true.

No argument about the downsides, but has the code changed there? Last I heard it was permitted in Maine.
https://www.hearth.com/talk/threads/wood-and-oil-on-one-flue-yes-you-can-or-in-maine-at-least.41161/

 

[begreen]

Contact Obadiah for info on burning in the 203. Ask for Woody, he used to own one. They may have the manual for it too.
https://woodstoves.net/cunningham/cunningham-203-wood-stove.htm

 

[bholler]

No argument about the downsides, but has the code changed there? Last I heard it was permitted in Maine.
https://www.hearth.com/talk/threads/wood-and-oil-on-one-flue-yes-you-can-or-in-maine-at-least.41161/

What I read said they have adopted nfpa 211 and irc without exceptions. But that could have been inaccurate. I know there were claims made in that thread that were inaccurate. Someone said it was legal in PA which is wrong. Also combination units are required to be vented into separate flues as well. That is why the newer ones have 2 outlets.

But again regardless of legality it is a bad idea.

 

[jetsam]

If he had one flue, he would have to unhook the oil burner every time he swept. And even so, he'd end up with whatever crud fell down by itself between sweepings in his oil burner. I'd fix that immediately whether or not the state says it's legal.

Running an insulated liner for the wood stove will also greatly reduce your creosote generation, in addition to being safer.

Expect more creosote this year than last year if you don't fix the flue, since you are moving to less-dry wood.

Also look into insulation. If it's balloon framed, chances are good you can blow insulation in behind the plaster and lath. You should be able to blow insulation into the attic regardless of construction style.

 

[begreen]

If he had one flue, he would have to unhook the oil burner every time he swept. And even so, he'd end up with whatever crud fell down by itself between sweepings in his oil burner. I'd fix that immediately whether or not the state says it's legal.

The oil burner would likely be a side tap with any crud falling down below that thimble to the cleanout.

40ft of chimney is very tall stack so even if the stove was the only appliance on the chimney, the draw would be a serious issue. Wonder if there is a barometric damper on the oil burner connector that is also regulating draft for the wood stove?

 

[bholler]

The oil burner would likely be a side tap with any crud falling down below that thimble to the cleanout.

40ft of chimney is very tall stack so even if the stove was the only appliance on the chimney, the draw would be a serious issue. Wonder if there is a barometric damper on the oil burner connector that is also regulating draft for the wood stove?

Yes there probably is a baro damper which does regulate draft which also introduces dilution air cooling the exhaust and causing creosote issues

 

[begreen]

Yes there probably is a baro damper which does regulate draft which also introduces dilution air cooling the exhaust and causing creosote issues

Yes, that is what I was thinking along with the cooling that's going to occur over a 40 length of pipe. Sounds like a situation where cleaning twice a season is necessary and maybe monthly if the wood is not fully seasoned.

 

[EJJohnson]

Thanks for responding. I figured that I would get some comments about the oil furnace and wood stove on the same flue, I have looking around on this site for a while doing some research. When I installed the stove I talked to some local professional stove installers and chimney sweeps (they are customers at the auto garage that I work at, and are some of the better ones in my area) they said as long as the chimney was installed before 1999 and had two thimbles (mine was) than according to the state I am fine. I know that it is not the best way but it is what I have.

I got the rotary cleaner just so I could keep that stack clean. It does have a clay liner in it. The furnace is a side tap and the baro is 3-4 pipe ft away from the thimble. I did install a throat damper in the stove pipe to tame that draft a little. When I start the stove I was letting the pipe thermometer (magnetic) get up to 500- 600 degrees to clean out anything that might have collected in the pipe. My attic was converted into living space by the previous owners of the house so I can't put deep insulation there. I do have 1/4 in of foam board under the siding, so that helps a little. I was thinking of installing double bubble insulation on my basement walls. One good thing is my wife does not like the house to get too hot.

The stove and the pellet furnace make the house feel a lot nicer, and buying 1100 gal of heating oil and keeping the thermostat at 60 was a little cold. As a side note the chimney is a two flue, the second flue is a fireplace on the first floor. When I had that swept the fellow doing the cleaning said it was the tallest fireplace chimney he had ever cleaned. Again thank you for responding. Now about that secondary burn. How can I tell if it is lit, or because it is a older design is it just hit or miss. Thanks.

 

[begreen]

500-600F is hot if that is a surface thermometer. It would mean that the internal temp was 1000-1200º. What does the thermometer read during normal burning, say an hour or two after the stove was started?

Now about that secondary burn. How can I tell if it is lit, or because it is a older design is it just hit or miss. Thanks.

Give Woody at Obadiah's a call. He owned one

 

[EJJohnson]

I try to keep the stove between 300 to 500 degrees, running it hotter when I first start it for a short amount of time. I am using a surface mount thermometer. I take it I should not let it run above 400 degrees on the initial start.? I bought the stove at a local Amish store, not at Obadiah's, would Woody mind that? I would not want to bother him if it did. I have read his previous post on the stove, which did encourage me to buy it. I had an old non air tight parlor stove hooked up the year before. I loaded it up with oak splits and rounds, shut everything down for overnight, came down the next morning and found the thermometer on the floor. The pipe had gotten so hot it reached its critical temp and was no longer magnetic! I never loaded that stove up like that again. Again thanks.

 

[bholler]

I try to keep the stove between 300 to 500 degrees, running it hotter when I first start it for a short amount of time. I am using a surface mount thermometer. I take it I should not let it run above 400 degrees on the initial start.? I bought the stove at a local Amish store, not at Obadiah's, would Woody mind that? I would not want to bother him if it did. I have read his previous post on the stove, which did encourage me to buy it. I had an old non air tight parlor stove hooked up the year before. I loaded it up with oak splits and rounds, shut everything down for overnight, came down the next morning and found the thermometer on the floor. The pipe had gotten so hot it reached its critical temp and was no longer magnetic! I never loaded that stove up like that again. Again thanks.

Have you had the chimney inspected for safety?

And like I have said before legal or not an install like this will never perform as it should. It puts you at much greater risk of a chimney fire.