Flue diameter - can I get away with an inch less than reccommended?

[keyman512us]

Interesting to get another perspective - and I take your point. Fortunately I can choose whether to use the top or rear exit. On the basis of the advice I have received here I will take the flue out of the top and straight up with no angles or bends. I will only be able to use 4 meters comfortably - as two of these would protrude above the roof and I don't think you are supposed to have more than 2 meters 'unsupported' flue above the roofline. I'll let you know how it goes.

Jonperry, first off, welcome to the site. It's always nice to hear from fellow woodburners' from "across the pond". Tell your friends about the site and snap a picture or two along the way of your project.

Hope the install goes smooth...

 

[TMonter]

Contact Jotul and see if they have charts for 5-inch flue.

 

[builderbob]

Non-Combustibility
HardieBacker™ cement board is recognized for use in non-combustible construction in NER-405.

Surface Burning Characteristics
When tested in accordance with ASTM test method E-84:
Flame Spread
Fuel Contributed
Smoke Developed 0
0
5

Thermal Resistance
(Approximate value) 1/4'' thick: R:0.13

Again yo asked for supporting information and facts.. I Challange you to prove where one can Refute all known code bases and manufacture tested listings I want proof you asked me to provide so I'm asking you to support your point with proof

BTW I am Nationally Certified that means since all states adopted the international code I can be hired in all 50 states The mass qualifications are that I pass the national battery of testing which I will find and scan proof of passage in 1997

British Standards and Codes of Practice, particularly BS6461,
CP403 and BS5449, relating to the installation of solid fuel appliances.


http://www.jotuluk.com/content/products/ProductArticle____3619.aspx

Installation of a fireplace must be according to local codes and
regulations in each country.
All local regulations, including those which refer to national
and European standards, must be observed when installing the
product.
Both an installation manual with technical data and a manual
on general use and maintenance are enclosed with the product.
The installation can only be used after it has been inspected by a qualified inspector.

3.4 Chimneys and flue pipes
A chimney can be linked to the fireplace and flue approved
for solid fuel-fired fireplaces with a flue gas temperature as
specified in «2.0 Technical data».
The cross-section of the chimney must be at least equal to
the cross-section of the flue. Please use «2.0 Technical data» •

I may not have jusisdiction in UK but I still can read their installation manual to see the correct way to do it

It is just such authoritative discussions, as Elk has provided above, that attract newbies like me as readers of this site. I have found in my short search there is a lot of hearsay, and biases, and unfounded opinions abounding in the hearth industry.

Consumers, such as myself, are grateful for as much factual-based evidence we can find.

Searching for a hearth product, in my mind, is a serious undertaking. I myself do not take it lightly. I appreciate being able to read factual-based evidence on which to make my decisions.

Opinions based on long experience are very helpful as well. And the combination of factual-based evidence, combined with experience-based opinions (even if they are not "research-study" based) make this site worth reading.

I would hope neither type of post would be discouraged---the site would be shooting itself in the foot if they were (in my humble opinion).

Thank you Elk for your contributions.

BTB

 

[stoveguy2esw]

Contact Jotul and see if they have charts for 5-inch flue.

as a manufacturer, i have to say TMONTER is correct , contact the manufacturer.without any input from the manufacturer other than it must be connected to a 6" flue , i would not recommend connecting it to a smaller diameter personally even though it may work after a fashion or with "caveats" (just my 2 cents)

however , with confirmation from the manufacturer (preferrably written) i would be satisfied and would go ahead with the install. (extra penny for good measure)

 

[elkimmeg]

Short version of a long story here is what I learned
I had a situation where GE gas dryers were installed in an assisted living development 62 units It seems that it is very hard to fir a 30" appliance in a 29.5 " finished space and connect a 4' exhaust vent I knew something did not look right and confirmed with the manual there is no way clearance could be met
The Architect claimed he spoke to GE in a letter to me and he spoke to so in so in engineering I requested that he have the converstion in writing and spamped ofn GE stationary.

there are times when you know you are getting BS well I waited no letter Finally I got a hold of GE engineering in TX First the person identified in my letter form tha architect did not work there
the second reply was that no one in engineering has the authority to provide information contrary to what has been listed tested and approved the only way is th submit a new setof specs and model for testing Do you have any idea the cost of that well it not going to happen. the head of engineering faxed me a letter sumurizing out conversation and that mike stasnton did not work at GE.. Well I approached the Architect and questioned his letter and info First he threatened that he has contacts in high places and he would see that I would be relieved as an inspector.

I asked him i=f he really want to do that I then showed him the letter from Ge and told him it was me in the position to have his licence reviewed the idiot ripped up both letters. I then told him I have the stamped originals in the office I also told him I was prepared to take this to the comittee that hited him Well 8 years later I'm still here and yess the washer dryer closets were torn out and re constructed to comply with clearances.

Morral of the story the manufactures can not alter tested and approved appliance listings without re testing and receiving approvals. Also note they can not advise contrary to what has been approved and listed. All thoses calling the manufacture for indivual relief are wasting their time and the manufactures time.. Any manufacturer that advises a soluting outside or contarary to the listing risk loosing approvals and possibly his /hers job

 

[myzamboni]

Elk, I don't question your knowledge . . . just the style of its delivery. Please keep sharing your knowledge, but try the approach a mentor would use as opposed to a police officer.

Thanks.

 

[BrotherBart]

Here we go again. Virtually all insert manufacturers list direct connection as perfectly fine with their inserts. Since when are they tested by UL, Warnack, Omni or anybody else using direct connections? Or any specific pipe size for that matter. Since when is the size of the pipe for any stove part of the UL, Warnack, Omni or anybody elses criteria for passing.

It ain't a safety issue Elk. It is a recommendation for optimum stove performance. The house ain't gonna burn down if the pipe does not suck enough smoke up the to the sky. It is just like the part of the manual that says don't burn wet wood. Gonna fail an installation because the wood pile out back is wet? I dun tink so Lucy!

If that pipe is only one inch in diameter and agency tested and listed to UL standards it passes for safety purposes. Stupid to install it. I will grant that.

Yeah, I'm bored and it is a slow month around here. :cheese:

 

[Gooserider]

Hi there
I have a Jotul3 CB which requires a 6 inch flue. I also have several meters of (very expensive) five inch twin wall flue. If I were to use this flue what would happen? Would it be dangerous? I will be installing the stove in an out building where there is no chimney - hence the need for twin wall. Many thanks.

Not venturing an opinion on the question directly, I would ask if Jotul makes different versions of the same stove for the US and Euro markets? If so, what size flue adapter does the Euro market model have? Since the poster says he can choose between top and rear exits, I'm assuming it has a reversible flue collar similar to the ones that come on the cast iron VC stoves?

If so, does Jotul sell a 5" flue collar that fits the stove, and is it approved for use on that stove?

If the standard flue size in Euro is 5", then I'd be amazed if a European stove co. didn't have a way to use that if the older versions of the same company's stoves did.

(It is worth noting that the manual for the Defiant-Encore 0028 specifies an 8" flue, and contains NOTHING approving use w/ a 6" flue, yet VC sells a 6" flue collar adapter for the stove, and everyone (including Elk) says it is OK to use a 6" pipe with the stove as long as one doesn't use the screen - but I've seen nothing in writing from VC saying it's OK. (It may exist, I just haven't seen it))

Gooserider

 

[elkimmeg]

from the original manual

"The defiant Encore may be used as a fireplace with the front doors open or removed,
But only when equipped with an 8” flue collar and the optional Defiant Encore spark
Screen placed in the opening for fire viewing. The Defiant Encore is not approved for
operation with front doors open if equipped with the optional 6” ( 150mm) flue collar "

 

[HarryBack]

Ive one question.....Why cant folks follow manufacturer's instructions?

 

[elkimmeg]

Ive one question.....Why cant folks follow manufacturer's instructions?

Sounds simple enought to me. I find that when doing inspection, that the only person that has opened the manual happens to be me

You would be amazed the number of inspection that fail due to not following manufacture installations.

Even more amazing is the installer, then questions me, when I came up with the concerns?

 

[saichele]

The downsizing of flue dimensions discussion is an oldie but a goodie, almost as good as the 'should I get it inspected' discussion.

IMHO, the key piece of this is that it's an OUTBUILDING. The guy's installing a Jotul with a full run of double wall pipe in his barn/shed/garage for Pete's sake.

The 'safety' issue related to flue size is draft and smoke - you're likely to get a little smoke in the shop when you open the doors to load. In a house or other space where people are sleeping, there's a risk there. Having a small flue doesn't make the stove any more or less liekly to burn the shop down. The stove may not draft properly, which may mean it doesn't burn very well/hot, but if that's a problem then you take out your [free] 5 inch pipe and buy some 6".

In other words, were it me sitting with a cold shop, a Jotul, and 4m of 5" double wall, I'd have that sucker installed in a heartbeat. Make sure you have the appropriate setbacks and a proper thimble for poking through the roof framing (even with double wall that's an issue). And if there's ever gasoline, paint thinners, etc in the space, I'd set the stove up a half meter or so on bricks or blocks.

Steve

 

[Rob From Wisconsin]

Elk, I don't question your knowledge . . . just the style of its delivery. Please keep sharing your knowledge, but try the approach a mentor would use as opposed to a police officer.

Thanks.

Good points, just a matter of "delivery".

Now, about "codes" & "inspections"......
Being an Engineer, I see the "natural" progression of "Codes" & "Standards".
Let me give you an example....
A gentleman I used to work with replaced a light fixture for his daughter & her
soon-to-be-estranged husband. Well, after their house went for sale as a result
of their impending divorce, he dropped "the bomb" that the light fixture was installed
by someone other than a liscensed electrician, as was required by Local Code.
Even though it was a 15 minute, simple job, he had no defense. He paid over $500 in
fines, regardless that it was done correctly.

It seems to me the "natural evolution" of Codes is to make it "legally" impossible
to do any handy-man job yourself, and require you to hire a "liscensed" (expensive)
craftsman.

Fortunately, our Township can't afford such intense meddling at this time, unlike some
places in the North East of our country...

Rob

 

[webbie]

but I've seen nothing in writing from VC saying it's OK. (It may exist, I just haven't seen it))

Gooserider

Yes, it is in writing.....but think about this. That is like selling a car and telling the people they can't use the rear doors for people to get in!

And, if someone used a 6" flue before the exact day VC said to, they would be going against the "manual". Just FYI, i would NEVER install that stove myself with a 6" flue, that is a 50% reduction for a stove that has vast sized door opening, and to think a customer is never going to use the front doors is ridiculous (in my opinion). So that should somewhat answer why "folks don't always follow manuals"...the manual says 6 is OK, I say it isn't. It is pure sales/marketing that VC made this adapter - that does not pass my test.

As far as Jotul 602, which were given earlier as an example of a stove that had a metric (4.9 or smaller) flue, this stove (with the 4.9) is the biggest selling stove in history, having sold well over 1 million units - yes, 95%+ with a 4.9 flue. Jotul 118 - 24" log, Lange 26" log - Morso - all with 4.9" flues.

So to directly answer the question - there are a number of factors which drive people to make decisions. Volgelzang stoves meet UL standards and are UL and EPA (exempt or approved).......but they don't meet some people standards. If everyone had all the money in the world and there were never any "in-between scenarios", then things might be easier. But if I had a chimney that only a 5.5" flex would fit up, I would use it- for sure, with most stoves.....yes, even though it is the equiv of a 5" when the corrugation is taken into account.

BTW, a quick look at many European Morso stoves including the large 2BO shows 120mm flue outlet:
120 millimeters = 4.72440945 inches

Flue size of European 602 (same stove as here except for flue collar): 123mm = 4.8"

So I was wrong about the 4.9", these stoves are closer to 4.7"
Jotul F3 is 150mm, which is 5.9" (Europe)

Elk is correct when he says the real test should be a draft test. It goes without saying that the F3 would work closed with a 5" flue and that the Encore would work closed with a 6" flue, but the concern is whether they would leak smoke out the door when loading.

So although I advocate following the manual....there always must be flexibility to match the situation. If we are going to follow the manual, then 5.5" flex liner should not even exist - yet it turns out it is a BIG seller. The alternative is usually not lining those chimneys at all.

Back to my original point - the forum and all this stuff would not even be needed if we followed the manual and manufactures literature. We could just have a big link here that says "Ask questions" and then when you clicked it, the page would say RTFM. (code for read the manual). We also would not need to advise people on what stove to buy. After all, there is printed manufacturers literature which tells us 100% which stoves are the best ones! It used to be Buck stoves, but now I think it is VC (cast), PE (steel) and Harman (pellet).....with a little Woodstock and HearthStone sprinkled in for soapstone.

But personally, if I had that 6" tile flue and could only fit a 5.5" down it, I would welcome the opinions and experiences of those who have done it MANY times....

Back to the VC flue collar thingy - why doesn't VC provide some sort of a bolted latch that assures people will not open the front doors? How are the people who buy the house in 5 years going to know about not using the front doors?

With testing, like just about everything else, you pay your money and you get what you are looking for. What if we produced a stove and said "stove is designed to use only 1/2 load of fuel at one time"? wonder if the lab would test to that?

 

[BrotherBart]

Exactly Craig. Had Todd not reported his positive experiences here with the 5.5" liner I would not have been able to line the chimney for the stove in my basement office. Which as it turned out works great with the 5.5".

And a good argument could be made that when you ovalize that few feet of a liner to get through a constriction that a smaller completely round liner would be more efficient than a squished six incher.

 

[Todd]

But personally, if I had that 6" tile flue and could only fit a 5.5" down it, I would welcome the opinions and experiences of those who have done it MANY times....

I have a 6"x10" ID clay tile flue on an outside chimney. This chimney had sluggish draft and stove smoked every time I opened the door. I wanted to improve my draft and tried to follow the manufactures recommendations of a 6" liner but couldn't get her down. I took a chance on the 5.5" liner and glad I did. Draft now is outstanding, and no smoke out the door what so ever, even with a cat stove. I figured I'd be better off with an slightly undersized liner than a creosote factory making 6x10 clay tile liner with an outside chimney. Even if it's against code, I'm willing to bet that there are many people out there with similar setups that could have safer and better performance if they did what I did.

 

[elkimmeg]

jonperry64 My fault for doing this earlier, Welcome aboard the hearth and good to see members from over the pond

 

[TMonter]

Rather than argue about what is legal or not, lets see if we can contact Jotul and get a recommendation on the flue.

It would be even nicer to have a Jotul rep trolling the boards to answer questions.

 

[precaud]

T, Jotul isn't going to say anything outside of what the manual says. I asked them about using a 5" flue for an F100 a couple years ago and they wouldn't even acknowledge that model was sold in EU markets with that size of collar!

And I agree; I'm astounded that more manufacturers don't have reps with a visible presence on this board. What better place on the 'net for creating some good PR and customer relations?