reducing flue size on wood stove

spinachqueenAugust 2, 2009

We had a chimney fire and had to reline it with a 6 in stainless liner. The original flue size was 8 inch. My vermont castings wood stove has a 8 inch flue size. Will it operate properly on the 6 inch flue? Should the size of the flue be reduced at the back of the stove or continue to use the 8 inch stove pipe and reduce the flue to 6 inch at the thimble that goes into the chimney

Any advice will be appreciated.

Thank you for reporting this comment. Undo

Reduce it at the back of the stove.

    Bookmark   August 2, 2009 at 9:18PM
Thank you for reporting this comment. Undo

Some Vermont Castings stoves - the Defiant, for example - were designed and built to function properly only when connected to a minimum 8" flue. Your stove may not work well at all with a 25% reduction in flue size. I would not connect to a 6" flue without first consulting with a certified chimney sweep or knowlegable stove shop. It may be that the 6" ss liner's smooth interior surface increases draft enough to make this change practical, but do check first.

    Bookmark   August 5, 2009 at 5:37AM
Thank you for reporting this comment. Undo

The point mainegrower brings up is quite true. The height of the chimney would influence the operation also. I think in your case, with the reduction at the rear of the stove, you have essentially redesigned the stove to operate with a 6 inch flue. In addition to the consultations mainegrower recommends, there are a few things you can do to adjust for any changes that may occur.

Most important would be to keep the liner cleaned. That may require cleaning it once a month if you use it 24/7. The cleaning will keep the inside diameter of the liner from being reduced further from soot and creosote. Adjust the damper or air input adjustments a bit more open than before and add less wood at first. In other words, you will have to change your usual habits of loading and regulating the stove until you find out what the new characteristics of the liner have created and then remember them from year to year.
There shouldn't be a tremendous difference but if by chance there is, increasing the height of the chimney may be needed. The extreme case if there is a big problem would be to replace the stove or rebuild the chimney or add an external flue system. I doubt you'll have to go there. I personally think your major areas of concern will be more frequent cleanings and damper adjustments.

    Bookmark   August 6, 2009 at 9:34AM
Thank you for reporting this comment. Undo

Thanks for all your advice on the new flue size. I did find a brochure for vermont castings that said the stoves produced before 1990 do not operate well on anything but a 8 inch flue. Ours was purchased in 1977!! I'm going to try reducing the flue at the back of the stove instead of at the thimble to the chimney. The draft seems really strong with the 6 inch flue but we do get some smoke when we open the top loading door to replenish the wood. I really hope this works as prices have gone up so much on all the better stoves. This one was about $700 when we purchased it.

    Bookmark   August 11, 2009 at 2:44PM
Thank you for reporting this comment. Undo

I have owned 3 Vc stoves over the past 30 yeras and currently heat with a wood furnace. The issue you bring up is important as posts have shown. As a tech rep for a former VC distributor, I advise check the manual...the 2004 Defiant model page 6 allows a 6" chimney, I quote: "NOTE: When installed with a 6" chimney connector adapter, the Defiant may not be operated with the front doors open." Last but not least, many states now require any woodstoves used in primary residences to meet EPA emissions standards. You may want to upgrade. Check out the Napoleon EPI 1900 for your heat equivelant if you use for primary heat.

    Bookmark   August 14, 2009 at 4:43PM
Thank you for reporting this comment. Undo

Some states are offering rebates to get rid of the smoke dragons too. Check out if your state has any programs.

    Bookmark   August 18, 2009 at 7:54AM
Sign Up to comment
More Discussions
Xtrordinair Fireplace
We were directed to a local shop selling this product....
Double-Sided Firebox Remodel Possible?
We recently purchased a house that has a double sided...
Feedback on MORSO 5660 unit with blower
Hi all- we're replacing our wood insert to get a sleeker...
Metal Fireplace Mantel; Distance & Depth
Hi, This is my first posting. I apologize in advance...
help please ! saw a picture, how can this be made?
Can anyone help me figure out these dimensions and...
Sponsored Products
Hampton Bay Outdoor Lighting. 12V Low Voltage LED 8 Piece Cast Aluminum Path and
Home Depot
Vegetable Vine Rug 8' x 10' - GREEN
$2,909.00 | Horchow
Floating Medallions Rug 2' x 3' - BEIGE
$69.00 | Horchow
Hampton Bay Ceiling Fans Westmount 44 in. Oil Rubbed Bronze Ceiling Fan 26607
$79.97 | Home Depot
Lagash Charcoal Rectangular: 5 Ft. 6 In. x 8 Ft. Rug
$499.00 | Bellacor
Tipton Trellis Dark Brown 84 x 52-Inch Blackout Grommet Window Curtain Single Pa
$34.99 | Bellacor
Reversible Grain Cutting Board - 1314
$42.99 | Hayneedle
14" LED Oil Rubbed Bronze Classic Battery Operated Gallery Light
$183.00 | Cocoweb
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™