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Old 24-02-2008, 14:07   #76
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Originally Posted by muskoka View Post
Sean, I designed and built schools on Hudsons Bay that were solely heated with stoves. I know how stoves work.

If your goal is to heat then you should to feed the fire with a dedicated outside air source. This allows the stove to work at maximum efficiency - you can still adjust the mix of inside/outside air supply if your goal is to control humidity.

To address your other concern - fresh cabin air - you open a window or dorade vent.
I agree with you, that from the perspective of maximum heat retention, it would be best to have a dedicted outside vent going straight into the firebox of the wood stove. It is true because in this case you woudn't have those "cracks" I'm talking about that admit fresh air, keeping the same stale, hot air in the living area. I agree with that. No change of internal air, so of course no heat will be pulled from the room and up the chimney.

However, if you open a window or a vent while having a dedicated air intake to the firebox of the wood stove, you have just 100% defeated your argument for having the air intake in the first place. Opening the window is no different than having the cracks bring air in, except that your window will concentrate the cold wherever you have it open.

If you want fresh air *and* heat, you need to use up your cabin air (while admitting new cabin air through the cracks) to provide fresh air to breathe and air out the place after a big... long... fart or something.

I hate to say it, but you don't have this right, even if you built places that were heated with wood stoves. If you think that there is a possibility for the fire to "suck oxygen" out of a living space, your concept of how a stove works is incorrect. Sorry.. I don't want to start an argument here.... but it's important to have the facts straight on the board.
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Old 24-02-2008, 15:21   #77
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The only way out of the problem as I see it is the old sailing ship galley trick of a concentric double flue.

The inside exhaust flue is longer than the outside inlet flue and is surrounded by the outside flue. The top of the outside flue has a downward facing rim which centres the pipe and extends outwards over the outer flue, then turns down to shield the permanently open vent holes which allow cold air to enter at the top. This air goes down in to the galley, being warmed as it does so by the hot inner flue which is carrying hot stove exhaust gasses outwards. The exit flue is longer by a couple of metres and the hot gasses are cooled by the incoming air. The exit flue often has a finned outlet system on it to always point downwind--assisting the outflow flow of gas.

In the galley stove there is a vent system which allows all air to come from inside the room,where the inlet air from the inlet flue replaces that drawn in through the stove grating. Alternatively the inlet can be extended downwards to the firebox itself. The flame is always enclosed and always vents gas up the chimney flue and nowhere else--and warm air comes in at all times UNLESS someone closes off the inlet flue and opens a hatchway--if the weather is warm--and admits cold air.

No one likes to be damp and cold. Any fool can be uncomfortable--but one needs to be comfortable and SAFE.

Make yourself a heat exchanger chimney system. It will not cost a lot more--if you touch the outer pipe you will not burn yourself and you can get rid of your cabin moisture via the stove because the incoming fresh warm air will replace it.

The last one I made was stainless steel. The inner tube needs to be at least three inches diameter, the outer tube needs to have about an inch clearance. It is MOST IMPORTANT is to make sure there are no pinholes or splits in the inner flue. The last thing you want is outgoing exhaust gasses contaminating the fresh warm incoming air.
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Old 24-02-2008, 15:41   #78
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That's a pretty good solution, Mike.

Just be sure when you are heating your intake air with the exhaust pipe, that you are checking more frequently for creasote buildup, as it builds up most when the exhaust gassses are being rapidly cooled.


Me, I think I'll stick to my simple single flue life. No need for complexity if there aren't any problems. It's now been 3 winters (the record this winter was -23F or -30C) using the Little Cod and it works so well, I couldn't ask for anything more.
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Old 24-02-2008, 15:59   #79
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Just be sure when you are heating your intake air with the exhaust pipe, that you are checking more frequently for creasote buildup, as it builds up most when the exhaust gassses are being rapidly cooled.
You are dead on Sean, creoaste will build and if it ignites your chimney will glow red (it happend to me, I was burning green wood ).
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Old 24-02-2008, 16:07   #80
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I always wanted a sail boat with afterburners...

Do you wood stove guys have thoughts on bulkhead mounted heat sources? My 28 footer doesn't have the cabin space for a dedicated wood stove. Likewise, any thoughts on the volume of wood burned over the course of a week...

Thanks
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Old 24-02-2008, 16:54   #81
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You are dead on Sean, creoaste will build and if it ignites your chimney will glow red (it happend to me, I was burning green wood ).
Yup. I lost my entire house and everything I own to a chimney fire in high school. Parents were in Cancun and my grandfather had left the stove roaring too much, while there was also a creasote buildup he didn't know about.

We went to sleep and awoke to our dog barking wildly and going room to room. Going through the downstairs kitchen, I could see into the room with the fire if I ducked low enough to be below the concentrated smoke level. BOOM!! The glass of the picture window blew out.

Funny thing is... you always think you'd have enough time to put on your pants, jacket and shoes to get out of a burning house. Complete BS! I was outside in my underwear, barefoot too. I manged to get a t shirt on and that was it. The heat and smoke were INTENSE.

Well, by next morning, the volunteer fire department manged to save the cellar.

See... problem was they brought the wrong hose connector and couldn't hook up to the water supply. They figured this out *after* they cut a "vent hole" in the corner of the house most directly opposite the point where the fire started. Well, you get what you pay for.
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Old 24-02-2008, 17:02   #82
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I always wanted a sail boat with afterburners...

Do you wood stove guys have thoughts on bulkhead mounted heat sources? My 28 footer doesn't have the cabin space for a dedicated wood stove. Likewise, any thoughts on the volume of wood burned over the course of a week...

Thanks
Burning a bigger floor standing unit like the Little Cod burns about 2' x 5' x 1' of good hardwood a week if it's cold as hell and you have it running 24/7. Really rough estimate. I can't quite translate my wood storage area into dimensions right now since I am getting on a new boat and sold the old in Nov.

Smaller stoves will go through even less, like this one, which could be mounted not up high on a bulkhead, but lower on a bulkhead with a custom shelf and heat shielding:

SARDINE STOVE INFO & SPECS.

And... take a look at the installations of the various models. Plenty of boats your size have found room:

Installation Views

Alternatively, Dickinson makes a solid fuel heater, which I suspect probably puts out as much heat as their diesel heaters. ha ha

Enough for your size boat, probably though:

Dickinson Marine - Newport Solid Fuel Heater
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Old 24-02-2008, 21:07   #83
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If you burn wood or coal--you will always get soot problems, sooner or later. The way to deal with them is to pass a brush up and down the flue using a pull through or rods--but if you burn diesel or kerosene efficiently there will be very little soot which results from incomplete combustion amongst other factors, which include volatile constituents of the fuel.

The best solid fuel is anthracite--but if one looks at the calorific content of fuels, oil fired heating beats them all unless you can get ashore frequently to bunker up the wood supplies.

Any flue needs to be kept clean--or you will get that roaring sound and a cherry red flue as the deposits burn off. What happens is the flue gets narrower--and the gasses passing upwards speed up until there is enough oxygen passing at sufficient temperature and speed to start ignition--and from then it really goes well.

We used to burn out the expansion chambers of motocross bikes in a specially modified forty gallon drum--they really go well, flames and heat aplenty. All that remains after it is finished, when one shakes out the chamber is a fine white ash. Of course you have to repaint it.

The pipe for the flue does not really get all that cold. However, condensed carbon particles and tar will form if there is insufficient oxygen present. It is better to restrict the fuel supply in the firebox rather than restricting the air inlet. This is the more common approach but produces carbon monoxide and soots up flues.
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Old 25-02-2008, 00:36   #84
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However, if you open a window or a vent while having a dedicated air intake to the firebox of the wood stove, you have just 100% defeated your argument for having the air intake in the first place. Opening the window is no different than having the cracks bring air in, except that your window will concentrate the cold wherever you have it open.
The volume of air required for combustion is much more than what is required for keeping the interior fresh. If you allow the combustion air to come straight from the cabin you waste more fuel. It's that simple.

Quote:
Originally Posted by ssullivan View Post
I hate to say it, but you don't have this right, even if you built places that were heated with wood stoves. If you think that there is a possibility for the fire to "suck oxygen" out of a living space, your concept of how a stove works is incorrect. Sorry.. I don't want to start an argument here.... but it's important to have the facts straight on the board.
"Sucking oxygen" is a figure of speech. It's all about keeping the interior air ventilated adequately & separately from the combustion for reasons of efficiency, health and safety.

If you don't want to start an argument it's best not to tell someone they're incorrect before you're clear on what they're saying.
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Old 25-02-2008, 01:56   #85
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Im glad we got off the SST shackles bit,I like the heater stuff,but is this argument gonna drag on the same.So Cheap crap dosen't last,good stuff does,DOH!!thats a no brainer.But sooner or later the good stuff is gonna get crappier as well or be beyond the average persons pocket.

I think Wheylan hit the nail right on the head.He didn't buy cheap crapp,he bought good stuff cheaper.Like the original thread implies(There's got to be a better way!!) Well it's obviouse,shop around,soon enough the shops that sell at over inflated price's will close down or stop to compeate on certain items that can be purchased cheaper elsewhere.

Now I'm not up to scratch on ya US of A shops,WM,Wallmart and whatnot,but I reckon if you don't sourse out the best price for the same item when shopping you are either too rich or too stupid to start with.And if you hear of a place with the same stuff cheaper but choose not to go and at least look out of some loyalty issue,you would be even more stupid.OK,Quallity is importent,there is no two ways about that(Thats a no brainer as well!!)Loyalty is not.Shop around.Mudnut.
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Old 25-02-2008, 02:52   #86
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The volume of air required for combustion is much more than what is required for keeping the interior fresh. If you allow the combustion air to come straight from the cabin you waste more fuel. It's that simple.



"Sucking oxygen" is a figure of speech. It's all about keeping the interior air ventilated adequately & separately from the combustion for reasons of efficiency, health and safety.

If you don't want to start an argument it's best not to tell someone they're incorrect before you're clear on what they're saying.
Gotcha. I agree with your top statement, but am fanatical about having fresh air in state boat cabins. I prefer the extra bit of fresh air from the combustion. But... I do agree.

I agree with most of your last one too, except the health and safety one. As I keep saying, it's not a logical possibility for the fire in a natural draft stove to interact with the air in your cabin, unless you have set something up wrong and are not getting a draft in the chimney. That's where people go wrong in thinking about a natural draft stove.
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Old 25-02-2008, 03:16   #87
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I agree with most of your last one too, except the health and safety one. As I keep saying, it's not a logical possibility for the fire in a natural draft stove to interact with the air in your cabin, unless you have set something up wrong and are not getting a draft in the chimney. That's where people go wrong in thinking about a natural draft stove.
Normally it shouldn't interact excepting a problem with the flue and, you can get freak wind conditions which can 'backdraft' the flue. It happens. An independent air supply for combustion creates a loop which doesn't include the cabin air. So even a badly drawing flue won't smoke you out.

In this system you'd get your fresh air makeup through a hatch, dorade, mechanical vent or whatever. You can also fine tune this volume of air separate from your fireplace.
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Old 25-02-2008, 04:31   #88
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Hi GANG.......Seeing as how I just read the installation manual on the stove site, listed in this thread I thought I may as well throw this in...who knows this may become a new "anchor thread" !! : )

· Avoid creating a “Low Pressure” condition in the space where the stove is operating, such as by operating an exhaust fan. A low pressure condition could cause poisonous gasses to be drawn out of the stove and into the room. Some fuel will during combustion separate carbon monoxide and generate it in the burn chamber. Carbon monoxide is toxic, so please follow the guidelines in this manual to avoid smoke “roll out” from the burn chamber. You can prevent a low pressure condition by providing adequate outside combustion air within 24" of the stove. Keep a port, hatch, or window open while operating the stove! Install a carbon monoxide monitoring device and a smoke alarm, and maintain them as directed by their manufacturers.
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Old 25-02-2008, 05:07   #89
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Antagonistic and/or combative language does not make an argument more convincing.
We can be emphatic, without becoming belligerent.
Please, let’s continue to engage is stimulating & energized discussions & debates, without any personal criticisms(stated or implied).
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