Using 6" chimney pipe on a 8" cat stove

[PARKBOY]

I have an opportunity to trade my Buck model 18 for a Buck Model 91 Catalytic stove but the only problem is I have 6" chimney pipe and the 91 has a 8" flue and would like to know if it would be ok for me to reduce the 8" to 6" or what kind of problems will this create? thanks alot

 

[Renovation]

I have an opportunity to trade my Buck model 18 for a Buck Model 91 Catalytic stove but the only problem is I have 6" chimney pipe and the 91 has a 8" flue and would like to know if it would be ok for me to reduce the 8" to 6" or what kind of problems will this create? thanks alot

Since the 6" flue will have about half the flow rate of an otherwise identical 8" flue with the door open, it's more likely to allow smoke roll-out on reloads. Short answer--risk of smokey reloads.

 

[jtb51b]

How much 6" chimney do you have? How well is it insulated? I knows its not reccommended but if you have a TON of draft on that 6" pipe you might just be ok.. Keep in mind it would be a non correct install and probably not insurable, some folks don't mind this tho.. Its up to you.. That 91 is a monster heater.

Jason

 

[lethal dose]

was wondering the same thing. just got my stove and 6" flue/pass through/ chimney installed. buddy of mine is going to be getting rid of a MONSTEROUS buck model 94 nc which is practically new and used very little. there is a good chance i could get a great deal but REALLY don't want to have to replace $1,200 worth of chimney. OR i may go wood/coal furnace route someday and most utilize an 8" flue. hmmm?

 

[Renovation]

I've got the same issue--free 6" on hand--and investigated it endlessly.

The danger is smokey reloads.

"You just have to ask yourself: do I feel lucky?" -- Dirty Harry

 

[lethal dose]

i've not heard the lore about insurance companies minding. i can't imagine they would care if you went from 8" to 6" as long as you were code compliant and clearances were met. i don't know that it would be "not correct" considering they make 8"-6" adapters for just about every kind of pipe imaginable.

 

[lethal dose]

congratulations on your 1000th post, george!

 

[Renovation]

congratulations on your 1000th post, george!

LMAO!

Thanks for noticing, I was planning a private celebration.

I can't see much of a safety issue with a 6" pipe on an 8" stove, but expect insurers, manufacturers, inspectors, etc. to refuse to sanction it just to avoid liability. The Blaze King King manual says something like "An 8" flue is required, unless approved by your local inspector." Translation: "not responsible".

 

[begreen]

Don't do it. With your short stack, you need everything to be optimal for draft.

 

[lethal dose]

what if we were talking more along the lines of 18'-21' vertical rise. the deal on that buck is tempting but i cant see spending all the dinero on another chimney when this one is brand new, as long as it's safe.

 

[Renovation]

what if we were talking more along the lines of 18'-21' vertical rise. the deal on that buck is tempting but i cant see spending all the dinero on another chimney when this one is brand new, as long as it's safe.

You could try it, and resell the Buck if it spills smoke. Someone please correct me if I'm wrong, but I don't see a big safety danger, though smoke roll out on reload would be annoying and unhealthy.

 

[begreen]

Would you really recommend this for a 9ft flue? Have you tried this?

https://www.hearth.com/econtent/index.php/forums/viewthread/69056/

 

[Renovation]

what if we were talking more along the lines of 18'-21' vertical rise.

I calculated on that too, and here's what I got:

Chimney:
6" versus 8" pipe diameter considerations.

height/dia/insidetemp/outsideTemp/DraftPressure,N/m^2/flow,ft^3/min:
14/8"/68/20/5.2(0.02water")/164
24/8"/68/20/8.7(?water")/219
14/6"/68/20/5.2(0.02water")/88
24/6"/68/20/7.3(?water")/103
Blaze King King specifies minimum 0.02" water minimum draft

As you can see, even a 24' 6" pipe has nowhere near the flow of a 14' 8" pipe. So smoke roll out on reload is still a risk.

 

[begreen]

what if we were talking more along the lines of 18'-21' vertical rise.

We're not. The OP would need to double his current flue height.

 

[Renovation]

Would you really recommend this for a 9ft flue? Have you tried this?

https://www.hearth.com/econtent/index.php/forums/viewthread/69056/

Manufacturers recommend at least a 15' flue, so I don't recommend a 9' flue of any diameter.

 

[lethal dose]

what if we were talking more along the lines of 18'-21' vertical rise. the deal on that buck is tempting but i cant see spending all the dinero on another chimney when this one is brand new, as long as it's safe.

You could try it, and resell the Buck if it spills smoke. Someone please correct me if I'm wrong, but I don't see a big safety danger, though smoke roll out on reload would be annoying and unhealthy.

i'm for sure willing to try. i just want my house to be "insurable". i'd be willing to bet if i DID get the buck or a wood/coal furnace and had a professional installer do the job, they would reduce the 8" flue to 6" and call it good. do it myself... that's a big NO-NO. my insurance company just told me they will NOT insure my house if i did the install unless a professional wood stove installer or licensed contractor offered a written statement declaring that the install meets code. so far, i have found ONE person willing to come and look at it and he has been quite smug and ignorant on the phone... i know what it's like to deal with smug inspectors. i should probably call a pro, act like i don't know anything (which wouldn't be a HUGE exaggeration) and say: "i'm getting a bigger stove with a bigger flue, can you hook it up to my chimney for me?" it's like... i just finished the install on my pass through and clean out and i had to extend the triple wall another 12" through the pass through to clear a concrete footer that surrounds my house so i could access the clean out. obviously, the t support is designed to keep the pipe 2" from the house (which also wouldn't work considering the thickness of my siding) so i welded one up made of 1/4 angle iron and sunk it into my foundation... i'm sure it will fail because i made it, even though me and my buddy both stood on it (almost 500 pounds). whew... sorry for the thread derailment. [/RANT]

 

[lethal dose]

what if we were talking more along the lines of 18'-21' vertical rise.

We're not. The OP would need to double his current flue height.

sorry i was vague. i was referring to myself, considering i am in a similar situation.

 

[PARKBOY]

Talked to a Buck Tech today and he says noway it wont work. Says I wont have enough draft and I wont get a complete burn.

 

[lethal dose]

Good to know. Looks like I'll look into a wood/coal furnace instead. Several available w/ 6" flue.

 

[davidmc]

Just wondered why both your buds were getting rid of the big Bucks?

I love mine......I have 15' of 8" and it works great.

 

[lethal dose]

Just wondered why both your buds were getting rid of the big Bucks?


I love mine......I have 15' of 8" and it works great.

They bought cozeburns I want the buck bad but refuse to replace 21" feet of brand new triple wall.

 

[webbie]

I would say, in general, I agree with the NO WAY on that particular stove.
Some stoves, like the VC Vigilant, were actually produced in various models with both 6 and 8" flues.

But that buck is a big honker. Don't do it.

 

[Boozie]

The manual for my Buck 91 specifies an 8" flue/pipe.

 

[nelraq]

A fellow down the road from me got a 'smokin' deal on a blaze king king model. He has it running on about 25 feet of 6" insulated SS pipe.
Every time I drive by - usually about twice a day - the chimney is belching out smoke - almost as bad as the old (poorly run) smoke dragons. I'm guessing that his wood is not adequately seasoned, but his chimney always smokes badly - not just for a few minutes after a re-load.

The BKking is a pretty big stove to be drafting through a 6" pipe!

 

[PARKBOY]

Just wondered why both your buds were getting rid of the big Bucks?

I love mine......I have 15' of 8" and it works great.

HE took it out of his house before he sold it and planned on using it in his new house but it wont fit in the fire place.