Smoke coming from chimney of BK Ashford

[Zanimal]

All season there was absolutely nothing coming out of the chimney of my Ashford when the cat was engaged.
Now just before it is about to rocket up in temperature I find that there is smoke bilging from the chimney even after I engage the cat.
I am unsure if my catalyst is not functioning properly or if I am seeing different effects because it is now above freezing.
The thermostat must be set higher and higher to keep the cat probe thermometer from going inactive. Much higher than the setting I was using for long burns earlier in the season.

In these photos the stove has been on the maximum thermostat setting for about 30 min after the cat became active.

 

[jeff_t]

Warmer temps may require a higher primary air setting, to compensate for the weaker draft. It seems to be pretty common to have smoke like that when burning with the thermostat wide open. The smoke is moving thru the cat too quickly. I think BKVP called it 'residence time'.

I find that getting the stove and the whole load good and hot, and then closing the air down over an hour or so, lets me burn with the thermostat closed all the way. At some point during the cycle, I need more heat than that, so I open it up for an hour or two. That seems to bring life back into everything, and I can smolder it for the rest of the cycle. This requires really dry wood, or else it just goes out. Most of what I am burning is 15-17%.

 

[Zanimal]

Thats the info I needed!
Thanks!

 

[begreen]

Good to know. I recently tried our stove out at 50F and was pleased to see that after 10 minutes there was secondary light off and no chimney smoke. This too requires nicely dried wood.

 

[jeff_t]

Every situation is different, but I find the BK takes a little more fussing with in the shoulder seasons. On the other hand, I only have to mess with it every day or two. I also find it easier to reload on a big, though relatively cool, coal bed. It gets charred and back up to active temp faster, and I can cut it back to a low setting sooner.

I had a similar experience with that Spectrum last weekend. I had a 600° stove top in less than fifteen minutes, and nothing but heat waves out the chimney. The interesting thing was that outside temp was in the mid 50s, but inside temp was in the upper 30s. Full load, no kindling, top down start, no draft issues or smoke back into the house.

 

[Seasoned Oak]

Wow i thought Cat stoves never smoked Now i dont feel bad about my EPA stoves that smoke occasionally when not hot enough.

 

[Zanimal]

Wow i thought Cat stoves never smoked Now i dont feel bad about my EPA stoves that smoke occasionally when not hot enough.

I think I started worrying a little too soon on this one. I turned the air up and now there is again nothing coming from my chimney.
Now all I need is another polar vortex and I'll be happy again.

 

[webby3650]

I randomly see some smoke coming from the cap. Mostly within the first hour of a cold start-up and again 16 hours later or so if I'm trying to stretch out a long low burn. I just kick the T-stat up for a few minutes to allow the cat to get active again.

 

[webby3650]

Something else to keep in mind is that when the cat is new its way more active. It fires up much faster and often gets too hot for a few fires. After a few months of use, they calm down.
This sounds like what you are experiencing to me.
Also do you have the blowers on the Ashford? The blowers will mess with the cat probe thermometer. The blower makes it read much lower than it actually is.

 

[Seasoned Oak]

I think I started worrying a little too soon on this one. I turned the air up and now there is again nothing coming from my chimney.
Now all I need is another polar vortex and I'll be happy again.

My englander smokes when i have too much air going past the tubes. I guess the burn tubes wont catch all the smoke if it goes by too fast.

 

[Highbeam]

Wow i thought Cat stoves never smoked Now i dont feel bad about my EPA stoves that smoke occasionally when not hot enough.

You thought wrong, but I think you knew that. My BK princess smokes like a freight train for the first hour or so of operation. It's emberassing really, thick, white, heavy, smoke until the cat lights off and then blue smoke that gets thinner and thinner until it is pretty much clear for the large majority of the burn. My BK is in my single story home so that thick smoke lays down on the ground. Excellent wood quality, very dry, the firebox looks good but the stack shows smoke.

The heritage I used to have and the NC30 are vastly superior in terms of clean burning. I can get secondary light off within 10 minutes and a clear stack on the NC30. Same wood.

 

[Seasoned Oak]

I really did think that Cat stoves smoked only for a few minutes until the interior temp got up to 500 Deg or whatever is the the temp at which the cat burns smoke. Should only take a few minutes to get that high. Non cat stoves need 1100 interior to light off.at least my harman does.

 

[webby3650]

I really did think that Cat stoves smoked only for a few minutes until the interior temp got up to 500 Deg or whatever is the the temp at which the cat burns smoke. Should only take a few minutes to get that high. Non cat stoves need 1100 interior to light off.at least my harman does.

I only get heavy smoke for a few minutes and really only if was a cold start.
It never lasts for more than 10 minutes, after that I only see a whisp here and there.

 

[rdust]

I load at night when I'm on 24 hour loads so I have no idea how much smoke it pukes during the warmer weather.

 

[Highbeam]

I load at night when I'm on 24 hour loads so I have no idea how much smoke it pukes during the warmer weather.

Due to the long hours of darkness here during the winter in the NW and the long burn times of the BK, I only load the BK at night. This time of year I start a fire at random times and for various reasons, that BK smoke is quite obvious.

I am currently running both stoves (BK princess and non-cat NC30) on the same wood and can compare the characteristics.

 

[begreen]

Hmm, that would seem to negate some of the purported clean burning qualities of cat stoves. Is this just with BKs or do Buck, Fireview and Appalachian stove owners also see this?

 

[mellow]

I have stopped burning for the year but the only time I got smoke was while establishing a fire and during reloads, once I got the cat hot enough and closed the bypass I didn't see smoke, the cat would stay active through the burn cycle till the coaling stage when smoke is no longer produced as much.

 

[Highbeam]

I have stopped burning for the year but the only time I got smoke was while establishing a fire and during reloads, once I got the cat hot enough and closed the bypass I didn't see smoke, the cat would stay active through the burn cycle till the coaling stage when smoke is no longer produced as much.

To be clear, my experience is very similar. Smoke like a freight train during startup and reload, then low or no smoke from that point on which could be 30 hours.

I expect any stove to smoke at startup, we all should if we're being honest, but the period of smoke is much longer than with the non-cat. Those tubes start igniting a secondary fire under the ceramic baffle board in very short time and the visible emissions go away. With the cat stove, the firebox is all steel and the smoke has a direct shot up to the flue so it smokes longer.

Despite this nuance, the cat stove is a superior heater for the 24/7 burner.

 

[Highbeam]

Hmm, that would seem to negate some of the purported clean burning qualities of cat stoves. Is this just with BKs or do Buck, Fireview and Appalachian stove owners also see this?

The clean burning qualities are based on the bulk of the burn during which the catalyst is engaged and fully operational. The regs don't appear to be concerned with the period of time before the clean burning technology kicks in.

Any honest woodburner will tell you that their fire smokes during startup and even the cat owners will know that engaging the cat is not like flipping a light switch, there is still some taper time as the cat ramps up.

 

[mellow]

even the cat owners will know that engaging the cat is not like flipping a light switch, there is still some taper time as the cat ramps up.

So true, especially if you engage the cat at a lower temperature of around 500-600 degrees, if I wait till the cat is at 800+ it is already cooking so when I close the bypass the smoke clears almost instantaneously.

 

[webby3650]

I also run a cat along with a non-cat when its cold enough. I see no noticeable difference in smoke output between the 2. They both will smoke on startup, but its for a very short time and not much. Not like a fog or anything. My Ashford will fire up in half the time the Oslo takes to get going. So really, I'd say it smokes less than the Oslo I guess. But all stoves fire up differently, in my experience steel stoves that load N/S fire up quickest.

 

[mellow]

You want quick, the ram air on these Appalachians loading N/S gets you up to temp in no time.

 

[Highbeam]

and there is the reason for the early light off steel cats. Reducing that warm up time would significantly reduce warm up emissions.

I have a confession to make. I do not do the top down fire starting method. Instead I use kindling and full size splits. Not a lot of little stuff. If I needed to reduce startup smoke, like say during a burn ban, I would increase the quantity of kindling and maybe even include small splits above the kindling. That might speed up the temp rise and reduce smoke sooner.

 

[begreen]

I too do not do top down fires. Our draft is good enough that I don't need to preheat the chimney. My method is the N/S Tunnel of Love™ with some dry kindling and a chunk of Super Cedar in between. Then cross another medium split over the SC fire. Ten minutes later I am starting to throttle her down. Dry softwood like doug fir rules for starting hot quick fires.

 

[robbydanilow]

Yeah the tunnel works well on my fireview. got the pipe glowing once on start up... Oops.