Woodstove question

Modeler · Dec 29, 2012

I've been considering replacing my woodstove. It's small and I have a hard time fitting the occasional long chunk of wood inside. My brother-in-law is doing some remodeling and is getting rid of his woodstove. It's nice and in good condition, but has an 8" flue; my current chimney is only 6". I know that 6" is considerably smaller (28 sq in cross section versus 50 sq in for an 8" flue), is it safe to neck an 8" flue down to 6" to fit the existing chimney?

Dave Workman · Dec 29, 2012

modeler614 said:
I've been considering replacing my woodstove. It's small and I have a hard time fitting the occasional long chunk of wood inside. My brother-in-law is doing some remodeling and is getting rid of his woodstove. It's nice and in good condition, but has an 8" flue; my current chimney is only 6". I know that 6" is considerably smaller (28 sq in cross section versus 50 sq in for an 8" flue), is it safe to neck an 8" flue down to 6" to fit the existing chimney?

Necking down to a 6-inch pipe from an 8-inch flue could cause some problems with the draw. Be sure to mop out the chimney; that is, broom out creosote and ash deposits.

Be sure to go inside the fire box and examine all of the bricks, replace any cracked ones.

Mark W. · Dec 29, 2012

If you install a stove in your house it has to meet the current state regulations for everything. From Hearth construction to flue. If it does not pass inspection by the local fire inspector and something happens (a fire) even if it has nothing to do with your stove. Your home owners insurance will not pay out a dime.

YOU NEED TO TALK TO THE LOCAL FIRE DEPT OR ONE OF THE BETTER WOOD STOVE STORES AND FIND OUT THE CURRENT REGULATIONS. Or you could be screwing your self something terrible.

hsullyc · Dec 29, 2012

I see it done often but they always do it rite at the stove.Usually don't have many problems if your chimney goes strait up with no elbows.Try to look up the specs or installation instructions on the new stove,and see what they recommend.

RVTECH · Dec 30, 2012

Any neckdown will inhibit draw and going from 8 to 6 is a lot but as previously mentioned better to do it at the stove and figure on a twice in the winter brush out as the smaller the pipe the greater creosote build up due to less air flow. I had to neck down from 8" to 7" at the base of my roof jack when I installed a new wood stove in my house several years ago and the buildup of creosote starts at the transition of the 8" to 7". This summer however I am going to replace the existing metalbestos pipe with 8" standard triple wall.

Modeler · Dec 30, 2012

That's kind of what I thought. I think I'll just pass.

DieselScout · Dec 30, 2012

My Dad had the opposite problem of many here. He needed smaller flew and had to reduce the diameter of his chimney to get the stove to draw. The smaller diameter made the gas move faster and caused the stove to draw better. Better draw lead to a hotter and cleaner burn. I would talk to someone who is familiar with chimneys and construction. They can tell you if its go/no go.