Pipe sizing guidance for new Napoleon 1100C Woodstove?

[ReedMikel]

Hi all,
I've ordered a new Napoleon 1100C Woodstove to replace a Treemont TAC-380 (circa 1985). Someone must have run a HELLacious fire, because the damper plate is warped and stuck 3/4 open. So I ordered the Napoleon. My question concerns the piping size and chimney. Old stove has 8" single wall pipe that runs 12' straight to roof. When I spoke with a Napoleon tech guy, he said I should NOT reuse the 8" pipe - I think he said it might not draft properly. He said to use 6". I called a local stove installer and he dismissed Napoleon's advice, saying that since it was a straight shot to the roof, that I could reuse the 8" pipe and chimney system. I sensed he might be a bit lazy (took 3 days to call me back), and maybe just wanted a quick install...

I purchased the new Napoleon 1100C stove thru DirectBuy, a members only club (kinda like Costco), so I have to find someone local to do the install. Seems like many fireplace/stove stores only install units that they sold to customer. I'm going to have to keep searching for a good installer in the Monticello, NY area...

One other question - what about the existing exterior/chimney, does that need to get redone if I switch from 8" to 6" pipe inside the house? Single wall vs double - pros and cons?

Thanks, and sorry for my first post being so lengthy
-Mike

 

[edyit]

try this link if you're looking for someone to install, odds are better off that one of these guys isn't a hack.

http://www.csia.org/search

 

[begreen]

I'd be inclined to change the stove pipe to 6" and increase it at the ceiling support to 8".

 

[ReedMikel]

try this link if you're looking for someone to install, odds are better off that one of these guys isn't a hack.

http://www.csia.org/search

Thanks for the link - there's only one company within 25 miles. I guess a lot of them do not get the education. Why am I not surprised

 

[ReedMikel]

I'd be inclined to change the stove pipe to 6" and increase it at the ceiling support to 8".

I was wondering about that approach, would definitely save some money. But would it perform even better if it was 6" inside and out? I'm not familiar with how a typical pipe changes as it goes thru the ceiling/roof. Can you point me to any info? Thanks

 

[begreen]

For sure the best solution is to have it 6" all the way. If the chimney pipe is old then maybe this is a good time to change it. This is a two story flue system installation diagram. If your installation is 1 story then ignore the 2nd floor chase and chimney section.

 

[ReedMikel]

For sure the best solution is to have it 6" all the way. If the chimney pipe is old then maybe this is a good time to change it. This is a two story flue system installation diagram. If your installation is 1 story then ignore the 2nd floor chase and chimney section.

View attachment 186281

Thanks BeGreen! My application is a 2 story high great room. It's about 12' ceiling height where stove pipe will penetrate roof. So a smaller diameter pipe will have better draft? If so, is it important to maintain that smaller diameter once it penetrates roof?

 

[begreen]

The Napoleon likes a good strong draft and may require 6" all the way. Still, with 12 ft of double-wall, 6" stove pipe running inside the draft may be ok unless the chimney outside is only 3 ft. Do you know how much chimney height there is outside?

 

[ReedMikel]

The Napoleon likes a good strong draft and may require 6" all the way. Still, with 12 ft of double-wall, 6" stove pipe running inside the draft may be ok unless the chimney outside is only 3 ft. Do you know how much chimney height there is outside?

There's about 5 to 6' of chimney height outside. Would I want single wall or double wall pipe inside? What are the pros/cons of single vs double? I also ordered their outside air kit.

 

[edyit]

single wall: cheaper in price.

double wall: better draft and less creosote formation due to less cooling of flue gases, tighter clearances to combustibles.

with 12' of inside pipe I'd go with double wall to a ceiling box then 6" class A from there on up.

 

[ReedMikel]

single wall: cheaper in price.

double wall: better draft and less creosote formation due to less cooling of flue gases, tighter clearances to combustibles.

with 12' of inside pipe I'd go with double wall to a ceiling box then 6" class A from there on up.

You're saying to use 6" double wall inside and 6" class A thru roof and up? Not sure what Class A is?

 

[edyit]

class A is insulated chimney pipe, in begreens diagram everything from the stove to the ceiling would be double wall and everything from the ceiling up would be class A.

 

[begreen]

There's about 5 to 6' of chimney height outside. Would I want single wall or double wall pipe inside? What are the pros/cons of single vs double? I also ordered their outside air kit.

Double wall. Most stove companies recommend double-wall for runs over 8ft. It will keep the chimney cleaner and improve draft. That will help performance during mild weather burning in fall and spring.