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Certified woodstoves

Started by Wrace, October 09, 2004, 11:20:54 AM

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Wrace

I just installed an epa certified wood-stove in my shop for supplemental heating. I've been disappointed with it's performance so far. I suspect part of the problem is me getting used to burning in these new type stoves.

The stove is installed in accordance with the mfgs. requirements, local and state codes etc. The stove is an Osburn Regal that is made in Canada. I have a 13 foot straight shot of black stove pipe up to the ceiling, and another 8 foot of insulated chimney above the roof surface. There is about 2 feet of chimney sticking above the peak of the roof.

The first issue I have is that this stove is spec'd to take a 17" log. In reality it takes a 15" log, 16" if you want to burn your hand up trying to wedge the log between the opening of the door. This situation is compounded by the small, tight firebox (even though the outside dimensions of the stove are fairly large).

While this is a pia, it won't be such a big issue when I start cutting my own wood and can cut the 15" length. In the meantime, ever try finding 14-15" firewood to buy? Not much of it out there, and most all rounds for sale are minimum 17". So I've been cutting 2" off my existing stock of 17" split wood. Not only is that a pia, it is not the safest thing in the world.

Anyway, not much I can do about the firebox size now. Lesson learned. I should have done more research on these new type stoves before buying. I purchased based on rated btu output and exterior dimensions of the stove, and believed the stated log size on the spec sheet. I liken this to the 2 man tent that really only holds one man. Or the 26 gun gun safe, that really only holds 23 if you don't want to scratch the heck out of your rifles when removing them from the safe.

On to the second problem I've been having with this certified stove. That is smoke out when starting and loading the stove. I get "puffs" of smoke rolling out the top of the door opening when starting the stove and when re-fueling the stove.

Not enough draft right? Well, it seems to me that the design of these new stoves complicates the whole draft issue. The firebox in this stove is completely enclosed, bottom, sides, back, and top with firebrick. In addition, there is a ceramic blanket that lays on top of the top row of firebrick, between the firebrick and the flue opening. When you look into the stove you cannot even see the flue opening.

Apparently the theory is the gasses and smoke are supposed to rise and roll out (towards the top of the door opening) and bend around the 180 degree turn and go up and over the ceramic blanket, finally making it's way to the flue opening at the center of the stove top. There is a pipe with holes in it right at that 180 degree turn that I think is supposed to burn off more of the gasses before they exit. I forget the technical term for that pipe... catalyst secondary burn or some such thing.

This seems to work well when the door is closed and the stove is burning. You can definitely see a bunch of gas movement and burning around this pipe through the glass door. It's a much different burn pattern then the old style stoves. Probably because on the old style stoves those gasses were just going up the chimney.

That doesn't help with the smoke out during re-loads though. Because there is such a very small and restricted area where the smoke has to travel. And because that travel path takes it right out to the top of the door opening and attempts to bend 180 degrees while it searches for the actual flue opening. The smoke usually takes the path of lease resistance, which is into the room.

When a fresh log is set in the stove, the fire bed is of course disturbed a bit. Causing smoke and ash to become airborne. With this sudden influx of smoke/ash the small opening for the draft to carry it to the flue opening is overwhelmed, and cannot take the volume all at once. So the smoke again takes the path of least resistance and goes into the room.

I liken this to the low flow toilets when they first came out. They didn't work at all. The volume of water was so reduced and the flow so restricted that the these things would clog if you just looked at them. I now have a "low flow" toilet, but it is pressurized and will suck the biggest turd down with ease.

Any ideas on what I can do about this smoke out issue? This is not a huge issue because the stove is in my shop. But  I would be highly upset if I were trying to use this thing to heat my home. Still, I'd like to work in my shop without the smoke though.

What about a flue fan or something that I could turn on just before I opened to door to re-load? Maybe turbo charge the draft suction during the re-load and start-up processes?

Btw, I do use the crack the door open routine to help build the draft before fully opening the door. This helps but only a little. As soon as the door comes fully open the smoke rolls out in the room.

Thanks
Wayne




MemphisLogger

Wayne,

Maybe I can help.

I heat most of my house with a Vermont Castings Intrepid II.

It too, is EPA certified and achieves clean burn through a catalyzed afterburner. Kinda like my old Volkswagon  ;D

I've found that the afterburner doesn't really work until the stove is warmed up. I start the fire using ERC, Soft maple, Birch or Poplar--usually with planer shavings and some kd cutoffs from the shop.

Once the subsequent Oak or Hickory is going good, I flip the lever to divert the exhaust through the secondary combustion chamber. I'll then duck outside for a peek at the pipe. If it's running good, the exhaust looks like a jet engine--no smoke at all. If it's smoking, I'll go back in and turn the air intake up and run it staight up the flue to heat it up some more before turning the catalyzer on again.  

I usually refill mine through the top "griddle" but sometimes throgh the front doors if the better half is boiling them "stink pretty" herbs  :D

I've found that you must TURN OFF the secondary burn to avoid back spill.

These systems also demand dry wood.  ;)      
 

Scott Banbury, Urban logger since 2002--Custom Woodworker since 1990. Running a Woodmizer LT-30, a flock of Huskies and a herd of Toy 4x4s Midtown Logging and Lumber Company at www.scottbanbury.com

Wrace

There is no provision to turn off the secondary burn on this stove. I've read the instruction manual more then I care to remember. The only control on the stove is the air inlet. Which of course I leave wide open when trying to start the thing.

I purchased the stove new 3 years ago, and am just now getting it installed. I'm sure there is no recourse with the manufacturer. I'm tempted to just remove two of the four top bricks and remove the ceramic blanket all together. This would pretty much give a straight shot right up the flue. Of course all the "efficiency" would be up the chimney as well.

Very frustrating. I feel like I just installed a very expensive, space hogging, stand for my anvil. Not sure I'll be using it as stove very much.

How does turning off the secondary burn on your stove work? Is there a lever that moves a plate out of the way to allow the firebox to breath directly into the flue opening?

Wayne

MemphisLogger

Sorry to hear they gave you no control  :o

Mine's got a lever that blocks the main flue, thus forcing the exhaust to make it's way through the ceramic/catalyst through a chamber lower in the back.

If I were you, I'd try firing it real hot at startup and running full air all the time--mine will stop working right if I don't keep the chamber heat up.  
Scott Banbury, Urban logger since 2002--Custom Woodworker since 1990. Running a Woodmizer LT-30, a flock of Huskies and a herd of Toy 4x4s Midtown Logging and Lumber Company at www.scottbanbury.com

Larry

I have been running a Vermont Castings Defiant Encore with a catalytic converter in the house for a long time.  Always operated the stove exactly as Scott described with no smoke problems.  I have had converter problems and on #3 right now (Owen Cornings covered them on warranty).  Ran the stove for a while without the converter and could not tell any difference.  I think I was still getting the secondary burn as I could see wood gas igniting above the wood.  

Try calling the company you bought the stove from and they may surprise you with some assistance.  I know Vermont Castings is a stand up make it right company.
Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

beenthere

Wrace
Sounds like you have a tough problem. Has the stove done this from the gitgo? And not gradually been getting worse as time goes on?  If I am hearing you right, you just recently installed it.  

I would contact the place you bought it, just to see if there is a suggestion as what to do. Also, the company would be a good contact, to see what they suggest to reload the stove.

I have the Vermont Defiant, and the by-passable cat. converter. I like it, but I was a bit slow to clean it initially, and when it gets loaded with fly ash, it won't work.  I thought it was a downdraft problem. Spent $200 to put a different cap on the chimney, cut down 5 trees that I thought might be interferring with the draft, and then FINALLY read the manual carefully. They said "clean the catalytic converter" and it worked perfectly.  ::)

If I open the door to load too quickly or without bypassing the converter, then I get a lot of smoke.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Gary_C

You may have too much uninsulated pipe above the stove. In a straight vertical run, the smoke will cool and become more dense. That alone can cause back drafts as you describe. Try adding more insulated pipe above the stove.

Gary
Never take life seriously. Nobody gets out alive anyway.

Wrace

Thanks guys, I think I fixed it. I got so disgusted with the thing I decide to disassemble it for inspection before hauling to the scrap metal yard.

I cleaned out the ashes, got my inspection mirror, flashlights, and stuck my head in there (not much room to work in these things). As I mentioned, there is a one inch, kind of fluffy, ceramic blanket that sits on top of the top row of fire bricks, just below the top plate of the stove. When assembling, there is a 6" square steel plate that is set on top of this blanket, directly under the flue collar. This is to prevent the blanket from being sucked up to the flue opening and blocking the air passage.

Upon inspection I found the front edge of this blanket had welded itself to the top plate of the stove. This is the edge of the blanket near the top opening of the door, where the smoke and gases were supposed to travel. It was almost like there were four "creosote glue spots" and the blanket edge had lifted up and stuck there.

This essentially had the already small smoke passage totally blocked. I pulled the blanket edge down and compressed it a bit. Fired the stove and it works well. There seems to be a very strong draft. You can really hear the air riping into the air intake and up the stove pipe. When you open the door, you can literally see the smoke being pulled up vertically through this small opening going towards the flue. Very little smoke spillage into the room now.

Thanks again.
Wayne

MemphisLogger

That's awesome Wayne!  

I love these modern stoves--they're so efficient! It's like driving a well tuned sportscar.  

You'll love yours too now that it's runnin' right.  :)  
Scott Banbury, Urban logger since 2002--Custom Woodworker since 1990. Running a Woodmizer LT-30, a flock of Huskies and a herd of Toy 4x4s Midtown Logging and Lumber Company at www.scottbanbury.com

rebocardo

Generally speaking I do not care how narrow a stove is, I want it long! If you have a stove 30 inches long in the firebox, you can easily shove coals backwards with a piece of fresh wood without letting much smoke at all into the room.

imo, A stove that is wide, but narrow in depth, can be a pain to refuel if it is a primary heating source.



SwampDonkey

Wrace:

Do you have a damper on your stove pipe above the stove. If not, install one and that will throttle the air flow. I'de be afraid of gettin that pipe too hot, wide open. Only open it wide when starting the fire, then close it off some when it gets going good. Your loosing alot of heat up that flu if its open wide all the time. Your room will heat much faster if you throttle the air flow in the pipe. ;)


"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

Tarm

Wrace
Dampers are a bad idea on EPA certified woodstoves. The stoves are designed to run without them. Oldtime stoves leaked a lot of air and were hard to control without a damper.  

SwampDonkey

I suggested the damper Tarm because Wrace indicated that there was a roaring gush up the flu. I'de be concerned. My air tight furnace in the house has no damper on the flu and I don't get that roar in my flu.
"No amount of belief makes something a fact." James Randi

1 Thessalonians 5:21

2020 Polaris Ranger 570 to forward firewood, Husqvarna 555 XT Pro, Stihl FS560 clearing saw and continuously thinning my ground, on the side. Grow them trees. (((o)))

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