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Outside Air Kits, Do you recommend them?

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by MountainStoveGuy, Jul 16, 2006.

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  1. tradergordo

    tradergordo Minister of Fire

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    MSG - way to take the initiative in directly contacting the manufacturers!

    Tom- this is DIRECTLY opposed to what you have stated. Someone on one side of this debate is ill-informed. Let's find out who!
    Are there really "many documented cases involving house fires due to out side air kits backdrafting" as stated directly from the tech at Jotul? How are we going to locate these documented cases? Are they just urban ledgend? Has the Canadian government also been duped somehow (their "residential guide to wood burning" document that I previously linked to in this thread says "The same research shows that wind effects around the house can reverse the flow in these ducts, which may create a fire hazard if the duct is connected directly to the combustion chamber").

    And what about Jotul's comments that "the scientific data done by the R&D department shows that there is little to no improvement on overall efficiency or performance" which is also basically what is stated in the Canadian document.

    I think the Jotul guy had a great answer for why all the stoves have the OA adapters and kits - politicians basically FORCED them into it! And in all fairness, I'm sure the politicians thought they were doing the right thing but at least if you believe these references to research and documented problems, it turns out to not be such a good idea.

    I know we are going to get to the bottom of this!


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  2. MountainStoveGuy

    MountainStoveGuy New Member

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    I was directed to Mark Lewis, the head tech to talk about the cases that they have documented. He is on vacation untill next week.
  3. MountainStoveGuy

    MountainStoveGuy New Member

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    Hearthstone called me back, The lead tech there stated this, "out side air kits have a resonably safe margin for operating properly, our stove design realy prevents and chance of that happening, BUT, our testing shows that there is no benifit in terms of performance to use outside air kits". Then the million dollar question, why do you manufacture them? statement "two reasons, the state of washington requires them, and in the rare case of a huge open fireplace competing for air, if used at the same time, can present a problem."
  4. tradergordo

    tradergordo Minister of Fire

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    Someone earlier in this thread linked to a manual for a boiler or furnace with a pretty high-tech outside air kit. The instructions in that manual specifically state that you should locate the outside air termination 2 feet above the highest expected snowfall height. That might not be possible for some people. Your concern also brings up another possible problem with outside air kits in general - unless there is a filter of some kind, they will probably be sucking in snow every single time it snows and that H2O is going directly into your firebox. Not sure what effect that might have on your burning, creosote formation, or the cast iron parts of the stove.


    MSG - sounds like more of the same, only I'd like to know what the heck "reasonably safe" means? Do YOU want "reasonably safe" or do you want "safe"??? At any rate, they seem in agreement that there is basically no benefit and they only sell it because politicians essentially forced them to.
  5. MountainStoveGuy

    MountainStoveGuy New Member

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    Last but not least, I just got off the phone with quadrafire, The tech i spoke to (which i no personaly) stated that there has never been a case of backdrafting in one of there stoves, he also stated that there isnt realy a reason to install one unless there is extreme negative pressure issues in the home. He stated that the baffle system is what realy prevents the backdraft to happen. He also stated that they arent very effective because the outside air kits arent air tight, and test have shown that there is little benifit except to combat negative pressure.

    So now i want to stir the pot alittle more, my brain works in funny ways, and i try to corralate everything i have heard from the manufactures this morning. Jotul is the only company that i talked to that stated they have documented cases. That brings me to two conclusions. 1) the tech was wrong, (mike is good i doubt that) 2) Jotul is the only one of the three that made catalytic stoves. Does this make sense? In a cat stove there isnt a baffle system with a buch of little holes that the heat and smoke has to travel through to get out. On a cat, there is very little resistance and i think it would be very possible. Now thats is my own conclusion, no one stated that.

    SO, i feel that its reasonably safe to sell a OAK to a customer that wants it for new construction and is buying a secondary burn stove. BUT, one thing that all three agree about is that they offer little to no benifit, and can actually be a detriment to the over all performace.

    The plot thickens. It would be intresting to see what other manufactures have to say on the issue.
  6. MountainStoveGuy

    MountainStoveGuy New Member

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    Now that im so courious, i got to lookin under all the stoves. They all seem to have the air hooked up to the cumbustion chamber, not through the ash pan. What caught my eye though, is that the some of the slots (like the mansfield, the 80K btu hearthstone beast) only has a .75" by 2" slot for combustion air. with that little hole, how much air can realy be leaving the house??
  7. thechimneysweep

    thechimneysweep Minister of Fire

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    Hearthstone's outside air intake openings are at the bottom rear of the stove. The outside air must travel through a passageway to the front of the stove, turn a corner, travel vertically through preheat chambers on both sides of the door and then enter the firebox through a narrow slot across the top of the viewing window. There might be an air pump strong enough to pull burning material off the floor of the firebox and backwards through all that chambering, but wind depressurization isn't ever going to do it.

    I'm amazed at the Jotul rep's response to MountainStoveGuy's inquiry. Jotul markets their stoves in something like 14 countries: I find it hard to believe that they would incorporate an outside air design that allows backflashing, just to benefit from product sales in Washington State. My guess is that, if Jotul really did have documented cases of backflashing, they have long since redesigned their intake system to eliminate the possibility.
  8. MountainStoveGuy

    MountainStoveGuy New Member

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    Tom ,just to clarify, it wasnt the rep, it was the tech department. Do you think that cat stoves would have a easier time to backdraft? You can see, from my last posts from the manufactures that im trying to be fair and clear on there opinions, all three said basicly that there a waste of time, and can be counter productive. Im not trying to justify either way on this subject, that for the readers to decide. Are we shure that the euro models are avalible with outside air kits? Some of euro stoves out there arent even avalible with outside air, (RAIS and SCAN). From what i can tell, Jotuls OAK intakes are very similar in design to the other stoves that i have on the floor.
  9. KP Matt

    KP Matt New Member

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    So can stoves which have no provisions in their desisgn for an outside air kit be installed in Washington state? Or do you jury rig something, or just use a passive "hole in the wall"? I notice the Jotul 602 and 118 manuals make vague reference to outside air, but they don't seem to have any fixture or knock-out that would allow for the easy installation of an outside air kit.

    As I understand it previously more jurisdictions required outside air kits; stoves which haven't been re-designed since the era when many jurisdictions required outside air kits naturally will still incorporate outside air kits into their design - it doesn't cost anything since they already have it, plus they don't want to miss out on the 6,000,000 potential customers in Washington state.

    People who buy such a stove that has a knock-out or an optional outside air kit are going to say to themselves "surely if the manufacturer saw fit to make provision for an outside air kit then that must be the safest, healthiest and most efficient way to go; so sure, I'll take the outside air kit - heck it only costs $50 more!"

    The real test is whether new stoves that have been designed and introduced since most jurisdictions did away with the outside air requirement still incorporate the new design - from a business point of view designing, testing, incorporating a new outside air feature might not be worth it given that all it does is give access to a market of 6,000,000. Completely different decision compared to retaining an existing outside air kit.
  10. MountainStoveGuy

    MountainStoveGuy New Member

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    If its Jotul's stance that there indeed dangerous, im shure they already know about it. Which brings up a good point, were the the other companies, for liability sake, not giving me the whole story? i dont think thats the case. Also its possible that these cases came from cat stoves that they produce, like Tom has said more then once, and i agree with him, it would be real hard to make the hot gasses and solid particles like coal and ash, reverse through a baffle system like the seconday burn system has, Jotul is the only company that i questioned that made cat stoves. I think this has something to do with it.
  11. Todd

    Todd Minister of Fire

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    I think the earlier Hearthstones were cat stoves, and didn't Quadrafire make some also? Keep up the investigation, this is getting very interesting.
  12. MountainStoveGuy

    MountainStoveGuy New Member

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    the 602,f118,f100 and 3cb, are not mobile home approved and do not have a outside air kit avalible for them.
  13. thechimneysweep

    thechimneysweep Minister of Fire

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    To answer one poster above, we can't sell a stove or fireplace in Washington State unless it has provision for direct connection to outside combustion air. This applies to all wood, gas and oil stoves, fireplaces, furnaces, water heaters, etc. Basically, if it has a fire in it, it must burn outside air.

    There are cases where direct connection to outside air isn't possible (like installing an insert in a fireplace in the middle of the house, with no exposure to an outside wall or crawlspace). In these cases, we can apply for a variance from the code authority, who might allow a passive makeup air kit installed in the nearest outside wall.

    On another point brought up above, it isn't the case that more jurisdictions required outside air at one time and then stopped requiring it. Thirty or so years ago, OA wasn't required at all. Then HUD began to require OA for stoves, fireplaces and furnaces installed in mobile and modular homes, which were of tighter construction than the stick-built homes of the day. Washington State passed its requirement much later in the game, about ten years ago as I recall, in response to the tighter building practices of today.

    Although not required, many woodstoves and manufactured fireplaces offered the outside air option even thirty years ago, including high-tech models from other countries like the Kent Tile Fire from New Zealand and the Stack Vista from Australia. The reason is, providing a source of outside combustion air to the fire can solve many common problems woodburners might encounter. Here are a few:

    Difficulty starting a fire unless a door or window is open.

    No difference in the burn when the draft control is turned from low to high.

    The smell of gas or oil exhaust from the furnace or water heater in the house whenever the stove or fireplace is burned.

    Cold drafts in the house whenever the stove or fireplace is burned.

    Smoke pouring in from fireplace B whenever there's a fire in fireplace A.

    Smoke leaking into the room through the stove's air intake opening whenever the Jenn-Aire, bathroom exhaust fan or clothes dryer is used.

    We've retrofitted outside air many, many times over the years to solve problems like these, and it definitely works. In fact, nowadays, here in Washington State where outside air is mandated for all new installations, we seldom hear complaints about these problems at all.

    As to the decision to connect your stove to outside air or not (assuming you're not in a mobile home or in Washington State), I'd say if you're not experiencing any of the problems that derive from burning room air, including those that appear above, there's no reason to do it. But if you are having a problem, please don't avoid the outside air solution because somebody told somebody they heard of instances of flashback. Unless, it seems, you've got a Jotul.
  14. MountainStoveGuy

    MountainStoveGuy New Member

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    Tom, i would be courious how you would adress the perfomance issues stated by all three manufactures that i called.

    Coaster, Jotul does not sell direct to the public, They as a manufacture rely on us dealers, to convey correct information to the consumer. Its the dealers responsibility to determine weither or not a air kit is needed. Thats why most dealers will tell you to avoide them, except the washington state dealers, where there required by law. And in Jotuls defense, they didnt say that there Jotuls were the problem, they were speaking on air kits in general, and stoves in general. Not once did they say that yes, jotuls should not be hooked up to outside air, nor did they say there was many cases of of back flash in our stoves. They worded it very carefully when they talked to me. The Jotul OAK system is just like the others, it terms of how it works and where it draws the air around. Jotul did mention that they absolutly do not recommed them, except in extreem cases of negative pressure, but i think that comment was made in the contex that there worthless on improving efficiency, not that there stove will burn your house down.
  15. MountainStoveGuy

    MountainStoveGuy New Member

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    Ohh no, i agree, we as american's love to file suit. Its a good thing that its next to impossible to happen. Im not going to loose any sleep. And, just because a manufacture states that they know of cases where this has happend, they didnt state that it happened because of there stove. That doenst make them liable for anything. I will say once again that from what i have learned here from tom, looking first hand at all the stoves, and what manufactures have told me, that it is near impossible for a modern secondary burn stove to backflash. Any one feel like commenting on the statements made by the manufactures off the topic of backflashing? I think we have that coverd now. EXCEPT, one point that never got adressed. Can a catalytic stove backflash? No complicated baffles in those types of stoves.

    All the manufactures agree to some extent that there a waste of time, and virtually offer no benifits in terms of efficiency, and can actually negativly affect the installation due to not properly sealing the penetration, and the leaky hookups.
  16. thechimneysweep

    thechimneysweep Minister of Fire

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    MSG, if you're referring to the tech support guys' statements that a direct connection to outside combustion air doesn't accomplish much, I would say you're talking to the wrong people. Being a dealer, you're in a position to have received bad information from tech support personnel in the past, as I have more times than I want to count. My bet is, if you talk to the design engineers who decided to incorporate the outside air option, they'd tell you the same thing I've been saying: outside combustion air is an invaluable tool to solve a myriad of problems a homeowner might experience with a woodstove. I'll also bet that, assuming the techie that answers your call knows what he or she is doing, if you called back and described one of the problems I outlined in my last post, that same techie will recommend outside air as a solution. How about a buck and a beer?

    I didn't really mean to pick on Jotul, was reaching for a little levity there. But it does seem odd that none of the manufacturers our company does business with has ever heard of a single incidence of outside air flashback, yet the Jotul guy claims to have heard of "several". On the surface, it would seem that if Jotul is in the unique position of having experience with several incidents of flashback not shared by the rest of the industry, there's at least a strong possibility those incidents involved Jotul stoves.

    Actually, I think it is more likely that Mike the tech guy was just shooting from the hip with his statement, and can't cite any documented cases of flashback at all. Since you've got his ear, why don't you call him back and ask for detailed info?

    Whoops, just noticed you've asked twice now what I thought about cats vs non-cats and the likelihood of flashback. I don't sell any catalytic models, but from what I've observed, the incoming combustion air goes through the same preheat chambering and airwash slot at the top of the door in cats as it does in non-cats.
  17. MountainStoveGuy

    MountainStoveGuy New Member

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    The techs i talked to are the senior techs at hearthstone and quadrafire, typically they shoot me strait. The Jotul tech is not the senior man ( i will be calling him next week ) but sounded fairly confident in his statement. I think i need to clarify something. I think people install OAK's for one of two reasons, or mabey both. 1st, major negative pressure problem and they need to isolate the chimney, 2nd the customer precieves that this is a way to get more bang for there buck out of there wood. So to wrap this thread up, I think these statements are true.

    1)outside air kits on MODERN stoves are not dangerous, however, they need to be installed properly per the manufactures specs.
    2)outside air can fix problems related to draft due to extreme negative pressure, but the typical installation wont require one.
    3)outside air does nothing for the burn efficiency of the unit, its not a performance enhancing tool.
  18. elkimmeg

    elkimmeg Guest

    Only the state of Washington expericiences flash back on outside air installations

    All mobile home installations have outside air flash backs

    No goggle searches comes with any incidents of wood stove outside air flashback incidents

    Only Jotul reports this being an issue.

    I talked to VC as you recomended and I mean head of productions. He could not recall one incident of outdoor air flash backs. Again he admits VC supplies the OA for sales in the state of WA plus mobile homes And it was Canadian code till recently. Has anyone checked to see if OA is required in Europe. What is their position on this issue.

    By the fact OA is required for mobile homes OA must serve a purpose though not needed in the larger residential dwellings.

    Why does the state of Wa require it? What do they know we should know? Let the post roll on

    Some raised a real valid point out door vents are required by code to be located 1' the average snow fall dept. I have asked the state what dept to base the location. 4 years later I have not received an answer. This is being hashed out now, because carbon monoxide issues on Direct vent exhaust exits from basement location appliances. People have died from snow blockage of the exhaust vents. I also would imagine if fresh air feeds to these appliances get blocked there is a chance for improper combustion and improped exhaust This being so then it is not a streech that it also could cause back drafting. Naturally all direct vent furnaces are suposed to have and oxegen depletion sensor that shuts them down or sensors that shut them down when levels of exhaust fumes reach dangerous levels, But we do not live in the ideal world in the case of these deaths the automatic sensors or shutoffs did not work. Here is another part of my final inspections tyennise ball works good in the 2.5" pvc vents. I stuff it in to cause automatic shutdown I give the appliance up to an hour and a half to go in the shut down mode
  19. MountainStoveGuy

    MountainStoveGuy New Member

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    Great post elk, thanks for checking. We have established pretty well that flashbacks arent likeley to happen, no need to argue weither its possible or not, its a moot point. not enough data to support it.

    I do beleive that are needed, in certain rare situations of extreem negative pressure. The common factor here is that all three said they do nothing for efficiency of the stove, and that there only purpose is to take the flue out of the house envelope where negative pressure exists.

    If washington is anything like my state, states make stupid decisions, and stupid laws, all the time. I would flip that question around, why is washington the only state that requires it? what does the other 49 states know that washington doenst?
  20. begreen

    begreen Mooderator Staff Member

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    When I bought the 3CB, there was no discussion of outside air. And no warning of getting a variance for it. Is this code provision for all houses or just mobiles? Seems like a lame provision unless qualified for certain types of construction. My understanding is that a lot of 3CBs are sold in state. This is the first time I've heard of the provision. If it's posted online, would you be able to pass on the code section so I can read up on it? Thx.
  21. thechimneysweep

    thechimneysweep Minister of Fire

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    The original intention of the Washington State Ventilation and Indoor AirQuality Code (VIAOC), Sections 402.2, 402.3, and 402.4 was to mandate outside combustion air for all combustion-containing appliances, including wood, gas and oil burners, that were to be installed in new construction. The reason was to prevent the problems caused by negative pressurization in new, tightly-built homes, which would also have some combination of kitchen or bathroom exhaust fans, clothes dryers, range hoods, attic ventilators, etc. already vacuuming air out of the home.

    Unfortunately, the eventual wording referred to "new installations" instead of "installations in newly built houses." Because of this wording, the majority of the code jurisdictions in Washington State have chosen to interpret the law as requiring outside air for all newly installed combustion-containing appliances in any house, even old leaky homes that are in no danger of developing negative indoor pressurization. Our service area spans four code authorities, and all four require a direct outside air feed for all new installations, even in older homes.

    There are exceptions: the code authority in King County, I'm told, enforces the original intention of the law, and only requires outside air hookups to appliances installed in newly constructed homes.
  22. begreen

    begreen Mooderator Staff Member

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    Thanks Tom. Great explanation and yes, I'm in King county. That explains why it wasn't an issue here in our old farmhouse. Thank goodness they had the common sense to interpret the original intent and not literal writing of the code.
  23. elkimmeg

    elkimmeg Guest

    The smart a-- answer is 49 other states voted for Richard Nixon in 1972 before he got impeached
    One state did not. who was right in this situation.. I think with Washington it has to do with the smog alerts air quality thing There are studies where OA improves combustion. Improved combustion reduces particle pollutants








    Unless I convert it to Adobe Acrobat I can scan it in and post to my web space 2003 has an intire chapter address in Combustion air.

    Here is the best description for requiring combustion air by code. I walk into your basement and start sizing it up there are other fuel burning appliances that the free flowing interior space has enough combustion air to support now you want to install a wood stove. that competes with the combustion air space. Well the additional required combustion air has to come from some place
    The obvious option is a fresh outdoor air feed.

    Code language also has wording concerning real tight homes ans requiring OA so mabe its not just the state of washington but lax code enforcement in the other 49 states except one town in the easter part of MA Letme get back into this I have to convert over to
    a windows cvomputer
  24. Shane

    Shane Minister of Fire

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    It seems that interpretation is where things always get screwed up. I run into many instances where someone interprets something. The worst one recently is finding a chunk of Simpson Duravent pellet flex installed in an attic the other day. (the new lighter stuff not the heavy older stuff) It was a matter of inches from combustible framing and was serving as an offset. I told the guy that he couldn't do that. He informed me that stove shop #1 told him that's the way to do it but didn't have the pipe, he then went to stove shop #2 who also told him he could do that and sold him the flex. "The tag says 0 clearance to combustibles". I shook my head and wrote up the inspection report condemming the stove. Scary stuff if those stores really did give him that advice.
  25. MountainStoveGuy

    MountainStoveGuy New Member

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    I participate in this forum to keep sharp. Expecially in the off season. I also require my employess to keep up here on company time. I dont want to be one of "those" dealers. Im very happy this thread created the intrest that it did. 1300 views is telling you that this is a foggy topic that people are intrested in. I can tell you i have learned alot myself.
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