old unlisted vs new unlisted stoves

Really cannot downsize from 8 to 6 safely with that stove.

Your stove might not have a label on it, but Papa Bears were listed by UL. The labels were often glued on as opposed to riveted and did not last long.

Given the cost of a new 8" chimney, your best course of action might be to sell that stove and get a newer unit which has a 6" flue and can be used with your existing chimney. Speaking of that, the existing chimney should be inspected to make certain it is in good condition and safe.

that is an old wives tale about not being able to reduce it down to six. as long as you do it right at the stove you will have no problems whatsoever. if you find a shop that will sell you one they will frown on the idea but of course,they want to sell you a new stove and or pipe.i and many people i know have been running reducers on fishers,allnighters,jotuls,vermont castings and others with not a hiccup. what if the hole on the stove came with a 6 inch from the factory,would it matter? no it would not.i am running a reducer on mine as we speak and have been for quite some time.creasote is no different than any other size.i hardly have any burning seasoned wood.

as for the UL sticker,there is no difference in the stove other than one had a sticker and one did not.nothing else is different.telling your fire marshall and insurance company that is a whole nother ball game.many of thse stickers or "labels" fell of over time.

Umm, get your popcorn here comes the show!

Here's how the relationship between woodstove flue collar sizing and chimney sizing has been explained to me:

Larger diameter stovepipe and chimney parts are more expensive than smaller diameter, to the extent that an installed bid for a woodstove with an 8" flue requirement can be hundreds of dollars more than an installed bid for a woodstove with a 6" flue requirement. Thus, the consumer has a pretty big economic incentive to choose a stove with a smaller flue size requirement.

Manufacturers know this, so they try to design their stoves to vent safely into the smallest possible flue.

HOWEVER: if a given model is submitted to the test lab with a 6" flue collar and doesn't pass the smoke spillage test, the manufacturer must either redesign, or resubmit that model with a larger flue collar, to accomodate larger stovepipe and chimney. This process pretty much ensures that the size of the flue collar on a given stove dictates the smallest pipe and chimney that can safely be used for the installation.

Thermal design engineering has come a long way in recent years, emissions have been substantially reduced industry-wide, and as a result, most of today's models are tested and listed with 6" flue collars. Nonetheless, there are still models with jumbo fireboxes, tall loading openings, or extra-restrictive secondary burn chambers, that require 8" pipe and chimney. There are even models with dual listings: examples include stove models with optional firescreens for open-door viewing, where you might be allowed to use 6" pipe and chimney for the installation, unless you intend to burn the stove with the doors open, in which case you must use 8" pipe and chimney.

Our experience in the field has tended to verify the unworkability of flue undersizing: we've been called in many, many times over the years to investigate smoke spillage complaints and found that the cause was undersized stovepipe and/or chimney. An examination of the math involved also offers both scientific and common-sense verification: a 6" round chimney has barely over HALF the cross-sectional area of an 8" round chimney.

Which is not to say that we haven't seen installations where a stove with an 8" flue collar vents just fine into a 6" chimney, in cases where some combination of factors such as extreme chimney height, temperature, location above sea level or a papal blessing combine to provide sufficient updraft.

Nonetheless, here's the rule of thumb: although a given 6" chimney might develop sufficient updraft to safely vent a woodstove with an 8" flue collar, that's not how you bet.

hornett22 said:

that is an old wives tale about not being able to reduce it down to six.

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Uh, what research do you base this "fact" on???

The Fisher double door is a large stove, which poses multiple problems for a smaller flue. First, there is the simple question of the chimney capacity in BTU. Every major chimney company publishes a chart as the the capacity of various chimney sizes.....and an 8" chimney is almost DOUBLE the cross sectional size of a 6" chimney (in sq inches).

Then there is the matter of the double doors on the unit.....any unit with larger openings requires a larger chimney in order to sweep the doors clear of smoke when loading and starting.

After you are done with those two things, you then have the actual temperature of the chimney. A 6" chimney venting the same products of combustion as a 8" chimney will get much hotter. I would assume that the triple wall chimney mentioned is probably older, which means it is not even up to current temp (HT 2100) standards.

An example of a capacity chart is enclosed........keep in mind that the chimney capacity must equal the MAX. potential input of the stove, and I would bet that a double door fisher burning in the lab could get up to 150K BTU plus.

To say nothing of the NFPA general rules about not downsizing a flue collar!

Heck, I am all for common sense, and if the question was whether a Jotul could be reduced to 5" (models that used 4.7 in Europe but a 6" adapter here), I would respond positively, but in this case it is definitely asking for trouble.

If we want to qualify that, we could say:
"If we don't care about codes and standards, and if we only want to open one door ever, and if we want to burn the stove at a reasonable setting and if the chimney is straight up and 20 feet plus, and if if if if if, then it would not be unsafe to use if you were on a desert island and had no other heat".

But that is a lot of qualifiers!

hornett22 said:

that is an old wives tale about not being able to reduce it down to six. as long as you do it right at the stove you will have no problems whatsoever. if you find a shop that will sell you one they will frown on the idea but of course,they want to sell you a new stove and or pipe.i and many people i know have been running reducers on fishers,allnighters,jotuls,vermont castings and others with not a hiccup. what if the hole on the stove came with a 6 inch from the factory,would it matter? no it would not.i am running a reducer on mine as we speak and have been for quite some time.creasote is no different than any other size.i hardly have any burning seasoned wood.

as for the UL sticker,there is no difference in the stove other than one had a sticker and one did not.nothing else is different.telling your fire marshall and insurance company that is a whole nother ball game.many of thse stickers or "labels" fell of over time.

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That is not a safe or good genral advice. just cause it works in one place does not mean it will work some other place some days i wish we did not have to follow the ruels i cloud sell alot more stoves but safety should come first in all cases and your house is a huge investment that i would not want to put at risk. as for not having a ul listing label and insurance you need to follow nfpa211 guidlines for an unlisted stove and maintain clearences set by nfpa211.

got my popcorn just in time!

Pook, theory and real world differ.

Would it burn? Of course it would burn! It would burn, and it would heat. But would all the real and potential problems outweigh the fact that it would work? In my opinion, yes.

i use year old metalbestos chimney pipe with my reducer on my double door fisher.no smoke if you open the door slowly.all i get is heat.

i guess on certain stoves it might make a difference but i have seen it work fine on all kinds of stoves as long as the chimney and flue pipe is set up correctly.i think this is a bigger factor.

the government can make all the standards it wants.you can't legislate common sense.if you want to let them in your life and control you,knock your self out.it is America,so you have that right.
i climb trees and buy all kinds of safety equipment by my own choice,no one makes me.mainly i buy it because if i'm tied in,it's easier to work. i daily see knuckle heads on ladders and free climbing trees to save a few bucks but again,that is their right.
do i think it's safe? NO

smart? NO

do i think there should be standards and a government agency to enforce said standards? NOOOOOOOOOOOOOOOOOOOOOOOOO!

take your bicycle helmet off and enjoy life.you can give me all the technical mumbo jumbo you want but my stove heats incredibly well and there is not smoke in the room and hardly any outside using properly seasoned hard woods.

BeGreen said:

Try to think of other folks, one shoe doesn't fit all. The difference is that many people visiting the forum are here for advice because they -don't- have experience. Often they get conflicting suggestions from friends and salespeople. They are here to try and sort it out and to get straight talk on how to install or run their stove safely and successfully.

I won't advise skirting code because for every post, there may be hundreds of readers in hundreds of differing circumstances. Yes, maybe 10 out of 100 can get away with bending the rules, but that doesn't mean it will work for the other 90%. Code often sets minimum standards. There's no harm in going a bit better than code either.

The Ash Can is a good place for venting variances with the mainstream and violating rules. Best to have that conversation there.

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i did think of others.it may not work for everyone.i disagree that saying it wont work for anyone isn't a fair statement either.i have never seen it not work.

no man said:

So far I think the no has outweighed the yes. Plus I agree with webmaster would it work probably but would it be safe???
I'm not looking for a short cut to use this stove. I'm looking for the safest way. Thats why I'm here, I have been reading this website for a few months and have had many questions answered that others have asked. I'm going to go with the gut feeling on this and look into the price of an 8in pipe and look around a little more for a different stove. Then go with the cheaper price. Thanks again for all the advice.

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You should be able to find a less expensive stove for well under $1,000. HD has them for 600 or 700 depending on what you want. Keep an eye out on Craigslist too for a lightly used one. I got a pretty good deal on our 30 there. No sweat.

Those old fishers are great old stoves. And the papa bear is monster. A friend of mine keeps his whole house at 80 with a baby bear. If your selling, I can garuntee it will move quick. They have a good following at least up here.
Downsides are they make lots of heat, so often people run then too slow and then cresote happens.

As someone who is experiencing smoke spillage as a result of a downsized flue liner, let me add this:

If performance is important to you, follow the manufacturers instructions
If not having a smokey house is important, follow the instructions
If being able to have insurance coverage is important, follow the instructions

If you have time available and the above issues don't concern you, experiment away. There is no law against taking responsability for your actions, but there are consequences for playing outside the rules when things go wrong.

I prefer letting the learned folks who write the rules (be they code or instruction manuals, etc) inform me (BTW, some of those folks post in these forums), and only deviate when I have a really good reason.

And there is this to consider on the cost side - system costs are only part of the expense - to produce a given amount of heat, the old Papa Bear will go thru more wood than a newer EPA stove that is installed IAW manufacturers instructions. Wood isn't free, even if you scrounge it. Scrounged wood takes time, and needing less wood will mean more time to enjoy the pretty flames.

So ask yourself this question - How much does your wood cost (time and money)? Then decide.

SAFETY is primary for my family and me, plus for my largest asset, my home. Everything else is far less important.

I'll go the 8 inch, when it is the manufacturer's spec, every time and without question.

Burn and cut safely!