First 2 Days with Ashford 20
- Thread starter msnell
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Is there any way to know for sure the catalyst is active if it’s below the glowing level of heat? If the bypass is closed and the cat temp is rising is that proof it’s definitely working? Or is it possible the temps would rise and the fire would appear healthy to the eye even with a non-active cat?
No, leave it be.
My holes for the probe were drilled correctly, and honestly I have a hard time pulling it out for flue cleaning every time. That's because it does corrode a bit on the tip where it contacts the flue gasses. So my inner hole probably isn't 3/16" anymore, either.
I wouldn't mess with wrapping anything around it, it'll just end up down in the stove somewhere.
Yes, if the cat gauge on the top of the stove says it's active, then it's active, even if it's not glowing. Active means it's above 500-ish F. And that does not yet emit visible light.
Often I can see the cat gauge rising when I dial down the thermostat (with, of course, the bypass already closed).
I.e. I reload while the cat gauge is still showing active. My wood is 80 F (b/c it's been near the stove for 24 hrs or more).
Once I close the door, I let the flames do their thing for about a minute (i.e. blowing the room temp air from the box). Then I close the bypass. Then I let it run wide open for a bit, depending on how fast all the splits "engage" with the fire. Then I dial down in steps.
If my "wide open" time was short (becuase the wood is really dry and fire spreads fast), the cat gauge is not yet very high, and then dialing down, I can see it go up while going to less flame.
The point is the cat gauge is not an indicator of "healthy fire". In fact, it is often the opposite - but you CAN run with an unhealthy fire (a smoldering mess) *because* the cat cleans up the mess before it gets to your chimney.
Running low, with little or no flame creates a lot of partially combusted gases and particles (smoke) - that is what the cat combusts and what leads to a high temperature of the cat. So dialing down the air (removing primary flame) can lead to a hotter cat.
Don't worry too much. Trust the cat gauge.
And verify occasionally that indeed you're running without smoke when there are no flames in the stove. (A no flame smolder in the first half of the burn will always produce smoke. If you don't see any, you're good.) That is the pudding that contains the proof.
Occasionally you will see some smoke because (I think) the thermostat adjusts the air a bit leading to some equilibration time for the cat during which some smoke makes it through. That's okay. And there'll be a lot of smoke when charring a new load (in my experience). That is what it is. Nothing I can do about that.
Thanks for all the feedback. I guess I don’t really understand exactly how the catalyst works and how it’s different & similar to traditional fires I’d think of.
It makes sense having a smokier fire gives more fuel to the cat , and I do think I’ve seen what you describe with cat temp climbing even with knob way down on low.
So I am consistently wondering should I err on the side of closing bypass earlier or later on a cold start? If I close it too early, I imagine the fire would just struggle to grow and keep climbing in temp? I see people mentioning the cat “catching” like it’s black or white that it’s active.
If I close the bypass when the flue is only 300, is it possible the fire would slowly still get to 500+ and it would then activate the cat on it’s own anyways? (I’m not doing this, just curious as a hypothetical)
If I close the bypass too late I’m mostly risking sending flames up deeper into the flue and starting a chimney fire. And maybe damaging the cat a bit at a time as well?
You've grasped the concept of the cat already: it allows for a slow-n-low burn (smoldering) because the energy emitted in form of fine soot and combustible gases are the "food" for the cat, which burns them and turns them into heat for your home. If you do that in any other stove, you'll lose a lot of the energy stored in the wood and it would be a mess in the flue and environmentally very unfriendly to boot.
Yes, the fire would likely eventually get to a point where the cat engages, but by then you've already sent lots of unburnt stuff through the flue (see above) and risk poisoning the cat with it. Therefore better go with the 2nd option, and monitor flue temperatures with a flue thermometer. Once that's above say 700-800F, you can safely assume the cat's hot enough for engagement.
You wouldn't necessarily start a chimney fire unless there's a lot of creosote in there, but you can easily exceed the safe temperature rating for the pipe.
On a cold start that can take 20-30 minutes, on a hot start you'll reach that in a few minutes, tops.
You'll get a better feel for it over time. This is okay.
Initially, (cold start bypass closing) I would simply follow the manual to the letter. It's written like it is for a reason. (this of course assumes the install is within specs; what's the flue height, stove top to chimney cap? You may have mentioned, but I forgot).
So when the cat gauge enters the active range, close the bypass.
After a while you'll notice you can be a bit sooner and immediatly see the cat light off (as in start glowing immediately upon closing the bypass).When it glows, it's always working. When it's not glowing, it's still working if the cat gauge shows active.
Yes, if you close the bypass far too early, the fire may struggle; if the flue is still cold, draft is poor, closing the bypass increases the impedance for exhaust flow a lot. But generally this should not be an issue when you are at or near entering the active range.
I agree with Tron above. I'd say 600 F on the flue probe should be fine already.
If your fuel is good (dry) and you operate the stove well, you shouldn't be overly worried about a few flames going up the flue when the bypass is still open.
You won't damage the cat by having the bypass open. (But don't run long term with the bypass open as it can damage things near the bypass.)
Initially, (cold start bypass closing) I would simply follow the manual to the letter. It's written like it is for a reason. (this of course assumes the install is within specs; what's the flue height, stove top to chimney cap? You may have mentioned, but I forgot).
So when the cat gauge enters the active range, close the bypass.
After a while you'll notice you can be a bit sooner and immediatly see the cat light off (as in start glowing immediately upon closing the bypass).When it glows, it's always working. When it's not glowing, it's still working if the cat gauge shows active.
Yes, if you close the bypass far too early, the fire may struggle; if the flue is still cold, draft is poor, closing the bypass increases the impedance for exhaust flow a lot. But generally this should not be an issue when you are at or near entering the active range.
I agree with Tron above. I'd say 600 F on the flue probe should be fine already.
If your fuel is good (dry) and you operate the stove well, you shouldn't be overly worried about a few flames going up the flue when the bypass is still open.
You won't damage the cat by having the bypass open. (But don't run long term with the bypass open as it can damage things near the bypass.)
The probe conducts heat through the probe to the meter dial so adding material won’t hurt anything but if I were you I’d run it as is. The magnet is good.
Unless it's not. The cats on these wear out and you can get the cat meter will over 500 and the dead cat is still dead. If the cat meter is above 500 and the chimney is pretty much smoke free then the cat is active. You should expect 10-12 thousand hours of active cat time before the cat should start showing signs of failure. It's part of life with a cat stove. They're super easy to replace.
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