7 inch flue on stove. Go to 6 or 8 "?

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Cuerno Verde

New Member
Jan 30, 2014
20
Colorado
I have an old Derco Grizzly with a 7" flue. What is the recommend pipe to reduce/increase to: 6" or 8"? No existing chimney to connect to will install new pipe as recommended. Thanks for the endless stream of guidance given here!
 
They do make 7" chimney I think, but have read that is costly. Normally you would go up one size to 8" with a reducer at the stove.
 
For me, it would depend on the size and heating needs of the house. Eventually you may decide to upgrade stoves. Most new stoves use a 6" chimney, the largest use an 8" chimney which will cost more.
 
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go with 7" or 8" and through olimpia who we get allot of our stuff through 7" is cheaper than 8". If you change stoves later and go with one that is 6" the 8 would be to big 7 would work ok still. but like fox said some of the big new stoves do use 8" so who knows you have to decide if you replace this stove will you be going bigger or smaller. I would say definatly don't downsize and use 6" though.
 
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Olympia only sells to dealers and sweeps.

Hart's Hearth carries Olympia's Ventis pipe and the difference in price on 7" and 8" is chump change.
 
whyis 7" oddball? we use 7" pretty often.
 
You are oddballs. ;)
 
Thank you for the direction!
Any of you folks know any thing about the Derco Grizzly(catalytic) line of stoves? I know they are out of business and a manual has been impossible to find, even through digging around this extensive site. Any info would be great. I did get a cool old sales ad from a moderator here.
 
allot of older stuff and allot of furnaces. And if it is a 6" outlet and we know the person does not burn well or clean often we might put in 7" to give them room for buildup.
 
to give them room for buildup.

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This stove must be old enough that there is no where to insert a catalyst thermometer. I am new to a cat system and would like to know if a magnetic flue therm. gauge would suffice for an indicator as to know when to engage the cat, or would a stove top temp be a better indicator. OR should I just drill a hole to accommodate a probe?
 
Modern cats require 500 degree exhaust temps to light off. If you have 500 degree temps in your flue then you are ready to engage. You can measure this on the flue with a probe meter or a surface temp meter. It doesn't hurt to wait too long to engage the cat, it's when you try too early that damage occurs.
 
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It's like a three wheeled car. What stoves did you install that specified 7"?

The Caddy furnace specifies 7" if you are using the oil burner option...
 
I have 7" flue on my Napoleon
 
We're talking about stoves here, not furnaces or antiques.
 
I am sorry highbeam thought we were talking about liners and I answered the question as t what we use 7" liners for.
 
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