Damper=Less smoke?

[Wisco Shepherd]

Curious on this, my Kuma hybrid runs great I can engage my catalyst within 7-10 minutes and it gets glowing right away. I get great secondaries, catalyst in the active zone, flue temps between 500-700 and a nice hot stove but for some reason she likes to stay smoke for up to an hour and a half after startup? I have a roughly 18-20ft flue (see attached) all double wall. I'm thinking that slowing my draft will increase residence time for my catalyst and allow it to better much on the smoke?
Wood is a mix of silver maple, elm, and some other hardwoods not much oak (next year it will be ready) and tests sub 18% on room temp splits.

 

[all night moe]

Interesting thought. Your idea incorporate a key damper? Easy enough to leave open if need be.

 

[begreen]

Interesting experiment. This is a hybrid stove. It might work as long as the reduction in draft doesn't kill the secondary combustion that happens prior to the cat.

 

[stoveliker]

Indeed strange that it keeps smoking for so long. Though all stoves smoke a bit on starting a load (imo), an hour and a half is long.

Your thinking is correct (residence time). Whether it works or not, and how it affects the secondary burn I don't know.

 

[Wisco Shepherd]

Interesting experiment. This is a hybrid stove. It might work as long as the reduction in draft doesn't kill the secondary combustion that happens prior to the cat.

Yeah my secondaries are usually roaring, which makes me think I have some to "spare".

 

[Wisco Shepherd]

Indeed strange that it keeps smoking for so long. Though all stoves smoke a bit on starting a load (imo), an hour and a half is long.

Your thinking is correct (residence time). Whether it works or not, and how it affects the secondary burn I don't know.

The other thought is to go super agressive in turning it down and never let it get roaring? But I do like at least a 10 min hot burn to get the catalyst going. I do also understand the concept of steam showing but it just seems a bit dark to be that and can linger around 10ft from the cap.

 

[begreen]

It's possible that the wood is outgassing faster than the tubes and cat can burn the smoke. If so, decreasing draft can work. Packing the stove tightly with larger splits slow down the fire as can turning down the air sooner.

Is the region fairly windy? If so, a key damper can also help compensate. As a simple test, reduce the chimney height. It may be the camera angle, but it looks like the chimney exceeds the 10-3-2 requirement. If so, and this is a windy area, bring it down to the minimum required.

 

[Wisco Shepherd]

It's possible that the wood is outgassing faster than the tubes and cat can burn the smoke. If so, decreasing draft can work. Packing the stove tightly with larger splits slow down the fire as can turning down the air sooner.

Is the region fairly windy? If so, a key damper can also help compensate. As a simple test, reduce the chimney height. It may be the camera angle, but it looks like the chimney exceeds the 10-3-2 requirement. If so, and this is a windy area, bring it down to the minimum required.

We are out in the open so we can get quite windy. I always turn down in 2-3 steps (100% open for 5-10 mins post cat engage, 50% for 5 to 10 and then maybe one more stop at 75% before final). Maybe drastically shorten the time at each stop or just eliminate a stop or 2?

 

[moresnow]

Any chance this is your first Cat equipped stove?
Original Cat that has lived through the stove operating learning curve?
Couple years old?
Has this smoke issue been developing/worsening over time?

Have you pulled the Cat for a bath since new?
Easy. Cheap. Cats seem to respond to that treatment well for me. If this cleans things (smoke) up nicely for a bit (short time) you will know your cat is on its tail end of usefulness.
Couple thoughts to contemplate! Good luck.

 

[Wisco Shepherd]

Any chance this is your first Cat equipped stove?
Original Cat that has lived through the stove operating learning curve?
Couple years old?
Has this smoke issue been developing/worsening over time?

Have you pulled the Cat for a bath since new?
Easy. Cheap. Cats seem to respond to that treatment well for me. If this cleans things (smoke) up nicely for a bit (short time) you will know your cat is on its tail end of usefulness.
Couple thoughts to contemplate! Good luck.

Hey! Yes year 2 on the first catalyst that thought has crossed my mind.

I did pull it and do the. Acid bath but I've never had issues with it staying in the active zone on my probe.

Next year will be a new catalyst for sure.