Which Way Should I Go?

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Oenoke

New Member
Sep 13, 2022
2
Maine
Hi Folks,

Here's what I have:

Chimney: internal, within an 1850s Cape Cod (2-story, with an "L"), with a 20-25 feet run from the ground floor to the top, now properly capped at the top against rain/critters/downdrafts. Chimney is clay-lined (6"x6" liner).

New Wood-Burning Cookstove: ABC Concept 2 Mini Air (a combination cookstove and convection heating stove). See the attached graphics.

Stovepipe Connection Options: out the top, or out the back. See attached graphics. I really want to connect out the back, because this will provide more cooking area on the cooktop, and it will make it easier to clean the stove, by removing the top fob, and cleaning downward, without having to disconnect the stovepipe (if it were connected out the top). The entire wall behind the stove will be brick, with the chimney immediately behind that.

Stovepipe: I intend to use double-wall 6 inch black stovepipe. (NB: the stove, which is European, came with a Euro-->US 6" adapter.)
The prior owner of the house had a fine example of a steam punk cookstove manufactured in 1923, which leaked smoke like crazy, and he implied that they sometimes had to open the kitchen window (in winter!) to create a sufficient draft to light a fire in that beautiful dinosaur. I believe their single-wall stovepipe vertical run out of the old stove was too short (12-18", followed by a 90 degree turn into the brick wall), which probably contributed to the poor draft.

So here is my dilemma: which way should I run the new stovepipe for this new cookstove?

Ideally, I want to get the best draft possible, and avoid 90 degree turns wherever possible. My initial idea was to increase the stovepipe's vertical run before entering the brick wall (and connecting to the chimney), and use 45 or 30 degree elbows to reduce the turns, but now believe that using 45s would force me to move the stove too far out into the room.

The dealer who sold me the stove stated they thought I had two practical choices for running the stovepipe from the new stove's back connection:
1) Connect a "T" to the stove's back connection (with the lower outlet capped and used as a cleanout), and then run a vertical pipe 36-48" straight up from the T, then a 90 degree elbow, and then a horizontal section of pipe straight into the wall/chimney. (See the 3rd graphic; I have already cut the hole for this; the lower hole is the old stovepipe entry into the chimney, to be sealed with a scrap piece of clay and refractory cement, and bricks.)
or,
2) Run the stove pipe horizontally, straight out the back of the stove for 12" and directly into the wall/chimney. (This seems to go against just about everything I think I know about how gases/smoke behave, and that the best draft comes from allowing the smoke to initially go straight up out of the appliance.)

If you think option #1 is the better choice, then the hole is already cut for it. If you think option #2 is the better choice, I don't care if I have to cut a new hole in the wall (and patch the one I have already cut). I just want the best draft for this new stove.

So then, which way do you think I should go?

If any of you have any questions, please don't hesitate to ask. I look forward to your thoughts, and explanation for the choice you make.

Concept Air 2 Mini-oblique.png Concept 2 Air Mini-rear.png Kitchen-stove wall.JPG
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,294
central pa
Hi Folks,

Here's what I have:

Chimney: internal, within an 1850s Cape Cod (2-story, with an "L"), with a 20-25 feet run from the ground floor to the top, now properly capped at the top against rain/critters/downdrafts. Chimney is clay-lined (6"x6" liner).

New Wood-Burning Cookstove: ABC Concept 2 Mini Air (a combination cookstove and convection heating stove). See the attached graphics.

Stovepipe Connection Options: out the top, or out the back. See attached graphics. I really want to connect out the back, because this will provide more cooking area on the cooktop, and it will make it easier to clean the stove, by removing the top fob, and cleaning downward, without having to disconnect the stovepipe (if it were connected out the top). The entire wall behind the stove will be brick, with the chimney immediately behind that.

Stovepipe: I intend to use double-wall 6 inch black stovepipe. (NB: the stove, which is European, came with a Euro-->US 6" adapter.)
The prior owner of the house had a fine example of a steam punk cookstove manufactured in 1923, which leaked smoke like crazy, and he implied that they sometimes had to open the kitchen window (in winter!) to create a sufficient draft to light a fire in that beautiful dinosaur. I believe their single-wall stovepipe vertical run out of the old stove was too short (12-18", followed by a 90 degree turn into the brick wall), which probably contributed to the poor draft.

So here is my dilemma: which way should I run the new stovepipe for this new cookstove?

Ideally, I want to get the best draft possible, and avoid 90 degree turns wherever possible. My initial idea was to increase the stovepipe's vertical run before entering the brick wall (and connecting to the chimney), and use 45 or 30 degree elbows to reduce the turns, but now believe that using 45s would force me to move the stove too far out into the room.

The dealer who sold me the stove stated they thought I had two practical choices for running the stovepipe from the new stove's back connection:
1) Connect a "T" to the stove's back connection (with the lower outlet capped and used as a cleanout), and then run a vertical pipe 36-48" straight up from the T, then a 90 degree elbow, and then a horizontal section of pipe straight into the wall/chimney. (See the 3rd graphic; I have already cut the hole for this; the lower hole is the old stovepipe entry into the chimney, to be sealed with a scrap piece of clay and refractory cement, and bricks.)
or,
2) Run the stove pipe horizontally, straight out the back of the stove for 12" and directly into the wall/chimney. (This seems to go against just about everything I think I know about how gases/smoke behave, and that the best draft comes from allowing the smoke to initially go straight up out of the appliance.)

If you think option #1 is the better choice, then the hole is already cut for it. If you think option #2 is the better choice, I don't care if I have to cut a new hole in the wall (and patch the one I have already cut). I just want the best draft for this new stove.

So then, which way do you think I should go?

If any of you have any questions, please don't hesitate to ask. I look forward to your thoughts, and explanation for the choice you make.

View attachment 298982 View attachment 298983 View attachment 298984
First off has anyone done a full inspection of the chimney? I can tell for sure it doesn't have the required clearances to combustibles from the outside of the masonry structure. That could be a real safety issue
 

begreen

Mooderator
Staff member
Nov 18, 2005
96,492
South Puget Sound, WA
Rear exit is going to introduce an extra 90º turn in the flue path which makes a total of three 90º turns by the time the smoke heads up the chimney. That is not going to help draft. It will be like lopping off 9 ft of the chimney.

Given the age of the house, it's possible that the main floor is experiencing negative pressure due to air leakage on the upper floor. This can be due to leaky 2nd floor windows, a leaky attic door or vent, etc. The effect of those leaks can turn the house itself into a chimney which pulls in air from the lower floor and exits out the numerous upstairs leaks. If this is the case, sealing up the upstairs will help a lot. Otherwise, it sounds like the stove will need an outside air supply.
 

Oenoke

New Member
Sep 13, 2022
2
Maine
First off has anyone done a full inspection of the chimney? I can tell for sure it doesn't have the required clearances to combustibles from the outside of the masonry structure. That could be a real safety issue
Hi bholler, Thanks for your note. Chimney sweep was the first tradesman I brought in, who inspected the chimneys and installed caps. A bit more context might be of interest:
- Maine has, by average, the oldest housing stock in the nation. Within a 50-mile radius of our house are literally hundreds of houses built in the late 18th or 19th century. I guarantee you the vast supermajority of them are not in line with modern regs, and very likely never will be.
- If you asked any tradesmen here about bringing old houses up to modern specs, they would tell you that it sounds great in theory, but won't happen due to 1) complexity, 2) cost, and 3) a skilled labor deficit.
- The old stove operated for 45+ years without incident with single wall stovepipe and old wood board paneling above a wood beam mantel upon the wall (yeah, I know). I'm replacing all that with a UL-listed stove, double-wall stovepipe, and a full brick wall. Any wood you see will be blocked and sealed from any heat. Ripping that part of the house apart for a reg that can be ameliorated is simply not an option.
Thanks again for your thoughts. I am curious: which way do you think I should go?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
30,294
central pa
Hi bholler, Thanks for your note. Chimney sweep was the first tradesman I brought in, who inspected the chimneys and installed caps. A bit more context might be of interest:
- Maine has, by average, the oldest housing stock in the nation. Within a 50-mile radius of our house are literally hundreds of houses built in the late 18th or 19th century. I guarantee you the vast supermajority of them are not in line with modern regs, and very likely never will be.
- If you asked any tradesmen here about bringing old houses up to modern specs, they would tell you that it sounds great in theory, but won't happen due to 1) complexity, 2) cost, and 3) a skilled labor deficit.
- The old stove operated for 45+ years without incident with single wall stovepipe and old wood board paneling above a wood beam mantel upon the wall (yeah, I know). I'm replacing all that with a UL-listed stove, double-wall stovepipe, and a full brick wall. Any wood you see will be blocked and sealed from any heat. Ripping that part of the house apart for a reg that can be ameliorated is simply not an option.
Thanks again for your thoughts. I am curious: which way do you think I should go?
That chimney can easily be brought up to modern standards with an insulated liner. The longer a chimney is used with combustibles in contact the more that wood get pyrolized. This leads to a very dangerous situation.

My advice is don't run any stove through that chimney until it is made safe.

Btw I work on many many 18th and 19th century homes. And yes making their chimneys safe is possible and very important