Production Woodstock IS

I'm still trailing behind in understanding the stove, but Gark, are you saying that the secondary combustion is contributing to the glow that some have ascribed to just the cat, and that you plan to cut back on the air earlier for more of a cat burn, which would last longer?

 

Yes, but I've only been wrong many times today (just ask my wife). Let's call combustion from the cat air tube "tertiary combustion" 'cause secondary combustion happens on the fireback where it's intended to. For some reason, I wish to avoid the flames around and above the cat sled.

 

Good question. I'm not sure the flames actually travel that far after watching it today. Since the exhaust flow travels up in front then back slightly and down through the catalyst and finally back and out I'd say the flames would have to be extremely aggressive to come into contact with the metal cat.

 

I do not believe so, at least not a S.S. combustor. Flame impingement was a problem with ceramic catalysts because it would rapidly heat the front / center of the cat. and cause it to crack. The classic 'breakfast bowl' shape to the face of a ceramic cat. was indicative of significant flame coming into contact with the cat. Between better (shielded) designs and all- metal cats., I believe that flame impingement is either no longer a problem or not the big deal it used to be.

Responding to your other post here: The glow you see in the cat cover is almost certainly due to the cat. temperatures. Secondary combustion just isn't hot enough to cause that kind of a red / orange glow IME. But a cat. running at 1,300F + degrees only has one basic way to send heat energy away and that is through radiation, 1/2 of which heats the cat. cover on the bottom. At 900 F, steel begins to glow a dull red. Like all of 'us', I have not had the stove long enough to really say with certainly but I believe it is the cat. heat driving the cat. shield's temperature.

It might take a little bit of time before I can catch up with some of you folks running these stoves with actual flames: I am running mine dark, the combustor under 1,000 F for some hours now (but active and burning the particulates) and it is 78F in the hall behind the wood stove. I am afraid that if I actually saw flames, primary, secondary or both, I would have to watch from outside with a jacket on 'cause it would be over 90F in the house

Brian

 

The while I did run the IS last night with those cool fireback jets burning, seems that most of the heat the stove made was radiated out the front window. Neither the top nor the front thermo's got much hotter while the light show played. Makes sense, because the PAH's are all being consumed in the firebox - little fuel left for the cat to consume. I bet the sides got hotter though but we don't monitor that.

 

When we put the thermometer on the front of the stove near the probe hole, does that register stove temp or stove temp and some cat heat with it? I haven't put my thermos anywhere but the stovepipe and just above the door.

 

registers a little lower than top temp at first and when the cat starts working it will catch up to and pass the top temp

 

One of the Beta testers found that the hottest spot on the stove was just to the right of top / center, above the door. That would indicate to me at least that it was cat. heat being sensed there because the 'radiator' is open front and back and those are the only two ways for the heat to radiate out of the cat and radiator directly.

You really have to reach inside to get a true internal firebox temp. because everything from the top of the firebox through the combustor is suspect (secondaries and / or a cat. burn).

Brian

 

Not sure what Woodstock considers stove temp, it doesn't specify where to place a thermo (in the owners manual) other than on the flue. A thermo on the front above the door, just to the right of the probe port sure seems to pickup the cat's heat. Beta testers last winter agreed. We have 2 thermo's on top too, they are always 100 - 200 cooler than the front thermo. Makes sense because the cat is tilted 30 degrees forward and the radiator disperses most cat heat.

 

Brian you got it. my beta woild consistantly run 175-200 deg hotter than stove top directly adjacent to the flue. amd the chimny temp an single wall pipe 12-14 in up from the stove top would run darn close to the sam amount but cooler. just to show how efficient this thing is. i dont understand how there can be that much temp difference in a short distance with nothing inbetween the thermometers except hot air

 

So this makes me wonder if the 700 degree stove Top temps that have been reported are due to the "tertiary combustion" (sled flames).

 

My wife asked me tonight why I needed 2 thermos on the new stove. I told her I was one of the crazies from the forum, and that's how I keep an eye on how this stove burns. I got an eye roll. Now I know she won't ask that again

 

when they droped my beta off guil one of the gearheads who ran it in the shop had the thermometer right next to the flue. i thought i read in the manual if you use the rear exit to put it on the cover plate on top so ner it if you top exit would be right.

 

Tell her is because you have not gotten the other three yet: the one that will probe firebox temps. (before secondaries or combustor), the cat. probe and the smoke pipe probe type thermometer.

Hey, I know a neat way to tie them altogether on one LCD screen and make records of the temps. over time. Maybe she would be interested in that?

Brian

 

When you say 'sled flames' do you mean the cats heat creating a glow onto the forward section of the sled along with the cat shield?

 

I got a laugh out of that. And the answer is "hardly"
She knows I enjoy it and she leaves me be

 

I am thermometer crazy -have 2 on top (one right where you said - on the plate covering the vertical exit), one on front and one on the single wall stove pipe (horizontal). The front thermo definitely reads cat heat. But where on the stove should we measure and consider max temp?

 

id say the top buy the flue. because that's what you monitor to engauge the cat. i and unh have both had the thermo burried during beta. the design engineer said it was ok during the test phase but not reccomended for production. not that it couldnt handle it but for longevity of the stove do.t go there. i personally did at least a dozen pulls of 700plus stove top readings during beta testing. they told me to run it hard and let us know what breaks.

 

Some have reported and I had flames (not in the firebox) up above the cat sled. You see them the same way as seeing the cat canister glowing. Only you see flames up there above and beside the cat canister, flames immediately under the top plate. We suspect caused by secondary combustion from the cat supply air.

 

and it's response was, Thank you may I have another!

 

Interesting. This is the first I've heard of this too. It looks as if I would have to view any potential 'sled flames' from looking up through the glass in the direction of the cat. And is this sled flames affect only happening when the air is low and the cat is engaged?