Reuse/Repurpose Oil Furnace chimney pipe for Wood Stove

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NorthwoodsJohn

New Member
Oct 17, 2022
2
Watersmeet, MI
Our old Fuel Oil furnace was decommissioned and replaced with a new Propane high-efficiency forced-air system with PVC power-venting in 2017.
The old chimney flue was capped off during the decommission.

I am looking to add a small wood burning stove in the basement of our 1100 sf Chalet style home with hope of reusing the existing chimney pipe.

The chimney pipe is roughly 25-30 years old double wall 7"ID and 9 1/8" OD and the new wood stoves I'm looking at have 6" collars. The chimney runs straight up from the basement in the same insulated wood-framed chase as the fireplace, through the first floor, loft and roof. The fireplace has its own chimney stack.

I can shine a light into part of the chase from the basement, 6' to 8' up to the sheet metal fire-stop and chimney pipe sections. I've not found any markings at this time. I'm looking for viable options as replacing the chimney pipe would be expensive and require removing siding on the house up the gable end to the top of the chase ~30+ feet.

I recognize I will need the chimney cleaned and inspected, perhaps the chimney sweep can determine if it is Class-A UL103HT
. can I use a 6" to 7" reducer to directly attach a wood stove ?
. can the existing chimney pipe be relined using 6" flexible or rigid ? (this should fit inside the 7" pipe)

I've been searching the Internet and have not found this topic yet

Thank you
John
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
31,103
central pa
Our old Fuel Oil furnace was decommissioned and replaced with a new Propane high-efficiency forced-air system with PVC power-venting in 2017.
The old chimney flue was capped off during the decommission.

I am looking to add a small wood burning stove in the basement of our 1100 sf Chalet style home with hope of reusing the existing chimney pipe.

The chimney pipe is roughly 25-30 years old double wall 7"ID and 9 1/8" OD and the new wood stoves I'm looking at have 6" collars. The chimney runs straight up from the basement in the same insulated wood-framed chase as the fireplace, through the first floor, loft and roof. The fireplace has its own chimney stack.

I can shine a light into part of the chase from the basement, 6' to 8' up to the sheet metal fire-stop and chimney pipe sections. I've not found any markings at this time. I'm looking for viable options as replacing the chimney pipe would be expensive and require removing siding on the house up the gable end to the top of the chase ~30+ feet.

I recognize I will need the chimney cleaned and inspected, perhaps the chimney sweep can determine if it is Class-A UL103HT
. can I use a 6" to 7" reducer to directly attach a wood stove ?
. can the existing chimney pipe be relined using 6" flexible or rigid ? (this should fit inside the 7" pipe)

I've been searching the Internet and have not found this topic yet

Thank you
John
Yes you can as long as you can confirm that it is listed to 103ht. It would be better if it was 6" but especially with your height 7" should be fine. You will probably need atleast one pipe damper to get the draft under control though
 
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NorthwoodsJohn

New Member
Oct 17, 2022
2
Watersmeet, MI
Thank you for your quick response.

Attached are a couple of photo's that include the capped end and a peek into the chase. I'm unable to locate any labels or see any stamped information. Would be great to determine if this is 103HT, inspect and reuse.

If I removed the cap (it is silicone sealed in place) might there be any stamp or labeling at the connector?

Is it permissible and safe to install a 6" flexible liner into the 7" core?

Thank you
John

20221017_190209.jpg 20221017_164932.jpg 20221017_164952.jpg
 

begreen

Mooderator
Staff member
Nov 18, 2005
97,984
South Puget Sound, WA
It may be ok, but we can't tell from the pictures. This may take some experienced eyes on site to inspect.