Question ,First hot fire in Ashford 30,2

[brewer69]

Had the first hot fire in my Ashford 30.2 yesterday, yea filled the house with smoke and had smoke detectors working overtime. My question is I built the fire than added 2 pieces of poplar and 3 pieces of ash waited till cat termo showed well into the active zone than closed the bypass waited 10 minutes and dialed it back, burned great cat thermostat was almost pegged and cat was glowing orange, stayed that way for several hours, I decided not to add more wood and just let it burn down since it was first hot fire, but when it was just mostly coals and the cat thermo was still reading well into the active zone the cat was no longer the bright orange color and just went dark( I assume no longer igniting gases) is this normal or the sign of something being off. Thanks for any info

 

[spudman99]

The cat will not always glow when working. So long as it is in the active zone it is working. Remember when the wood first burns it emits smoke. The purpose of the cat is to "eat" the smoke and reduce particulate matter escaping the flue. Once the amount of smoke decreases (or stops in the case of hot coals), then the cat is likely to go dark. At that point the stove is not emitting many particulates and thus complying with the EPA standards. So short answer is -- perfectly normal. Judge your stove by the active/inactive zones, that is all you need to do.

 

[stoveliker]

I agree with the above, the cat works when it's 500 F (or so) or higher. Glowing is only visible from 850-900 F and up.
So you have a range of temps where the cat works and you don't see anything. Just go by the gauge.

The cat will clean things up and provide additional heat in doing so.

 

[brewer69]

Thanks for the responses, much appreciated

 

[Burnin Since 1991]

Thanks for the responses, much appreciated

How are you liking the new Ashford 30.2? Are you new to woodstoves?

 

[brewer69]

Really liking it so far, fairly easy to use , puts off good heat and nice size fire box, I like loading North to south you can rally pack it full, easy to regulate the fire also. not new to burning, had Fishers, for years than more recently have had a couple Jotuls but this is my first experience with a Cat stove, so far so good

 

[Tron]

I like loading North to south you can rally pack it full

That's generally the way to do it. Because when loading E/W, round splits on top can roll forward and rest against the glass.
The glass itself probably won't mind that, but it makes a mess when you open the door.

 

[Burnin Since 1991]

Really liking it so far, fairly easy to use , puts off good heat and nice size fire box, I like loading North to south you can rally pack it full, easy to regulate the fire also. not new to burning, had Fishers, for years than more recently have had a couple Jotuls but this is my first experience with a Cat stove, so far so good

That's great. I'm replacing an older stove next summer and I'm likely going to go to the Ashford 30.2 The N/S loading is the tipping point for me. My wife's only input was for a brown stove, which the Ashford has brown as an option.
I've looked over all the stoves I could, based upon what dealers in my area carried and we were pretty sold on a Hearthstone but only E/W loading convinced me to look elsewhere.

 

[m37charlie]

Re catalyst glowing, or not:
Ignore the mention of steel. Black body radiation is purely a mathematical function of Temperature and fundamental constants like h, Planck’s constant, and c, speed of light, and k, the Boltzman constant. And quantum mechanics.
At 1200F you can’t see the black body radiation because virtually none is in the visible spectrum, all the photons have a wavelength >700nm and they’re all distributed in the IR spectrum.
Even when the thing is glowing bright orange or even yellow, the vast majority of the energy is IR, not visible.
At 1000K (727C or 1340F), a BK King catalyst, with a surface area 10.5x5x2” sides = 105 sq in is radiating ~3.8kw or ~13000 btu/h. Just the catalyst, mind you.
The radiated power varies as the 4th power of the temperature. So if it glows bright yellow at 1600K, that’s 85,000 btu/h.
When there’s just big devolatilized hardwood coals, the catalyst still facilitates oxidation of CO to CO2. But that’s not enough heat to make it start glowing.

 

[stoveliker]

While your calculation seems reasonable, there's no way the small surface area of the cat only is ever going to provide 85,000 btu/hr. I would wish...

 

[m37charlie]

While your calculation seems reasonable, there's no way the small surface area of the cat only is ever going to provide 85,000 btu/hr. I would wish...

Stefan–Boltzmann law - Wikipedia

en.wikipedia.org

Given a temperature of 1327K and a surface area of 105 sq in = 677 sq cm, it’s an inexorable law of physics. Considering that the combustion front BEGINS at the surface of the cat one can see, it’s entirely possible the back side is even hotter than the front.
Admittedly, my catalyst is usually radiating at about 1200K based on the color. So that’s only 27k btu/h.
Of course I have a bit of red-green colorblindness. …

 

[Tron]

Black body radiation is purely a mathematical function of Temperature and fundamental constants like h, Planck’s constant, and c, speed of light, and k, the Boltzman constant. And quantum mechanics.

True, but by definition a black body has an emission factor of 1, and no real material exists with that property. Stuff like Graphite with an emission factor of 0.95 is a good approximation, though. Steel can vary widely. The rather white base material of the cat is probably way off.
(That's also why more expensive contactless thermometers, aka temperature guns, which use this effect, often have a setting for the emission factor. But the lower it gets, the more inaccurate it gets)

 

[m37charlie]

My cat is steel, and the surface area of the steel mesh is small relative to the voids between. So when I am looking at my cat and guesstimating the color, I am mainly looking at the glowing gas - burning soot particles and organic compounds. Emissivity is an important fudge factor, but my estimate is that it’s at least 0.7-0.8 in the case of a steel cat.

 

[stoveliker]

I'm a physicist.
I have more than 2 decades personal experience judging (silicon) temperature from its color - and used dual wavelength pyrometers etc. which provided my learning feedback in doing so - BTW, I was able to see 550 C if I switched off lighting in the lab and switched off the ion gauge in the vacuum system.)
Your math works out afaics.

But, something is off as my cat surely is at times 1600 C. Yet simply by being there, I can tell it has never radiated at 85,000 BTU/hr.

 

[m37charlie]

I also have a physics background (undergrad deg) and have resumed the last 6 years after quitting MD office work.
Anyway, I was using the dimensions of a King as an example. Since the Ashford’s cat is 20% smaller surface area, at 1600K it would put out ε x 68k btu/h. Whatever ε turns out to be. Which might vary for ceramic vs steel cat.

 

[stoveliker]

I also have a physics background (undergrad deg)

I could tell
Good to have more nerds here (or maybe I'm only saying that to myself...)

 

[Dieselhead]

While you guys are being all smart here’s the reference chart I have posted by my stove to compare to my cat to