Question Catalytic Stoves and Creosote

[NhRocks]

I currently have a Pe Super 27, which is a great stove. We will soon be looking for a stove with a larger firebox and are considering a catalytic stove due to lower emissions and longer burn times.

Do the catalytic stoves run with a lower chimney temperature and if so, does this cause more creosote formation?

Thank you all for your help.

 

[begreen]

Welcome to hearth.com. Yes and yes, potentially. This is why it's recommended to have an insulated liner for insert installations and to use double-wall connector for freestanding installations. Straight up through the house works best.

 

[webby3650]

With properly seasoned wood and good burning practices there will be little difference in build up. 1 annual cleaning is typically all that's needed.

 

[NhRocks]

Thank you for your response. The suggested venting configuration makes sense based upon those factors.

 

[branchburner]

Do the catalytic stoves run with a lower chimney temperature and if so, does this cause more creosote formation?

As a rule yes, to the first question, but not necessarily, to answer the second. The lower flue temp results from the ability of the cat to burn smoke at lower temps. So while the lower temps would mean more condensation, more complete combustion would mean there would be less particulate to be condesnsed. You could have a cat running at low flue temps produce less creosote than a non-cat running at higher flue temps.

The key to a clean stack is not going to be the burn technology (or its flue temps relative to other technologies), but the quality of the wood, the flue setup, and the operating technique.

 

[Highbeam]

I conclude that yes and yes. In my home with all vertical, double wall, chimney I burn excellent three year seasoned softwood. I heat 100% with wood. I switched from a noncat hearthstone heritage (about 30 cords burned) to a blaze king princess catalytic stove. The flue temperatures on low burn are about half as high with the catalytic stove and the creosote accumulation is about double with the catalytic stove. The cat creosote is black and crunchy but the non-cat was brown and crunchy.

These drawbacks are insignificant when compared to the wonderful, beautiful, awesome benefit of thirty hour burn times and very low burn rate possible with a catalytic stove. I have a 9 month long burn season and 95% of the time I am burning low and slow. We love the long burn times possible with the cat stove.

 

[bholler]

The choice between cat vs non cat depends on your needs. If you have lower heat demands like highbeam and can burn low and slow most of the time a cat stove is absolutely the right choice. But for me i am burning hard most of the season so non cat is my choice. As far as creosote like others have said that comes down to fuel setup and technique. Most stoves even old smoke dragons can burn without making allot of creosote if you burn good wood and burn correctly.

 

[branchburner]

The flue temperatures on low burn are about half as high with the catalytic stove and the creosote accumulation is about double with the catalytic stove.

Isn't this a function of how you run the stove -- low and slow -- rather than of the burn technology itself? In other words, if one wanted the higher heat output of a non-cat but used a cat stove to get it, it would seem he could get lesser amounts of creosote than you do.

 

[Diabel]

I don not mean to derail this thread. But it appears that the BK cat stoves burn somewhat "dirty". On two or three occasions I have read that these stoves collects substantial amounts of creo. Is this the general consensus of these stoves?

I want one of the Ashfords, but I will have to think twice if they indeed are dirty burners.

 

[bholler]

I don not mean to derail this thread. But it appears that the BK cat stoves burn somewhat "dirty". On two or three occasions I have read that these stoves collects substantial amounts of creo. Is this the general consensus of these stoves?

No not at all if burnt correctly with good wood there will be little to no creosote accumulation in the stack. Honestly that can be said of just about all good new stoves but the bks and other good cat stoves can do that while burning low and slow which makes for long burn times.

Isn't this a function of how you run the stove -- low and slow -- rather than of the burn technology itself? In other words, if one wanted the higher heat output of a non-cat but used a cat stove to get it, it would seem he could get lesser amounts of creosote than you do.

Yes a blaze king should not be creating much black crunchy stuff. Something is wrong there It should be able to burn clean even on low.

 

[webby3650]

I don not mean to derail this thread. But it appears that the BK cat stoves burn somewhat "dirty". On two or three occasions I have read that these stoves collects substantial amounts of creo. Is this the general consensus of these stoves?

I want one of the Ashfords, but I will have to think twice if they indeed are dirty burners.

Not all for me. I get a very small amount of black and brown dust and clean only once a year, heating exclusively with wood.

 

[Diabel]

Not all for me. I get a very small amount of black and brown dust and clean only once a year, heating exclusively with wood.

I think that a lot of people still burn wet wood in these cat stoves. No temp thermos and smolder the fire, hence dirty pipes.

 

[rdust]

I think that a lot of people still burn wet wood in these cat stoves. No temp thermos and smolder the fire, hence dirty pipes.

The idea behind a cat stove is low burns that are cleaned up by the cat. i.e. Smoldering burns

I've burned a Princess for 5 seasons. Two seasons before burning the Princess I burned a Lopi Endeavor. My wood is all 3 years + seasoned, stacked in single rows off the ground with at least 3' between rows and top covered. It doesn't get any better.

My experience is identical to Highbeam, my non cat was brown and fluffy, the BK is black and somewhat crunchy. Wood with my Lopi wasn't seasoned nearly as well since it was my first two seasons.

That said I'll probably never own anything other than a BK stove. A little extra soot in the pipe is a small trade off for the outstanding performance.

 

[Diabel]

Granted, the long burns are unmatched but I suppose the trade off is dirty pipe. But dirty pipe means dirty burn correct.

 

[webby3650]

The idea behind a cat stove is low burns that are cleaned up by the cat. i.e. Smoldering burns

I've burned a Princess for 5 seasons. Two seasons before burning the Princess I burned a Lopi Endeavor. My wood is all 3 years + seasoned, stacked in single rows off the ground with at least 3' between rows and top covered. It doesn't get any better.

My experience is identical to Highbeam, my non cat was brown and fluffy, the BK is black and somewhat crunchy. Wood with my Lopi wasn't seasoned nearly as well since it was my first two seasons.

That said I'll probably never own anything other than a BK stove. A little extra soot in the pipe is a small trade off for the outstanding performance.

Ive just never found this to be the case with any of my Blaze Kings. Maybe my short straight chimney run has something to do with it? My flue is just as clean with as it is when I'm running a non-cat. I do let mine rip on a regular basis, whether I need the heat or not.

 

[begreen]

The temp the stove is run at also makes a difference. Some report clean glass all the time while others report black glass unless they turn up the thermostat. This is going to vary with the house insulation and sealing, the ambient indoor temp and the outside temp.

 

[rdust]

Granted, the long burns are unmatched but I suppose the trade off is dirty pipe. But dirty pipe means dirty burn correct.

I can only see if the stack is smoke free, not how "clean" it is.

The BK site shows the Princess at 2.4 gr/HR this is dirty than their other cat stoves. I have no idea what that means in the real world!

 

[Diabel]

I can only see if the stack is smoke free, not how "clean" it is.

The BK site shows the Princess at 2.4 gr/HR this is dirty than their other cat stoves. I have no idea what that means in the real world!

Yes, I agree. We assume that if the stack is smoke free then it should be a clean burn. But then why the reports of filthy stacks from some of the BK members? Maybe some type of more complex chemical/combustible reaction that some of us just can't grasp.

 

[JA600L]

Having low end control is awesome. I love running my hybrid on a low cat burn. However, when the wind hits on a frigid night I love being able to wake it from its nap and give me a high output secondary burn. You just can't beat secondary burn for max btus.

 

[branchburner]

We assume that if the stack is smoke free then it should be a clean burn. But then why the reports of filthy stacks from some of the BK members? .

From what I've read here, BK gets the longest burns of just about any EPA stove. This might mean that at some point in the burn cycle, even if the cat is active, the flue temps are the coolest of just about any EPA stove (assuming dry wood). If the cat is not burning all the particulate (and of course it won't burn 100% of it) the cool flue temps perhaps mean that little bit of remaining particulate is far more likely to condense inside the pipe?

I don't know if "filthy" is a word commonly used to describe BK stacks... seems like they are just slighltly dirtier/crustier. I know with the high flue temps of my downdraft stove I have NEVER had anthing other than light, fine brown powder. The shiny black crunchy stuff mentioned by the BK owners sounds like what I've seen in my fireplace or smoke dragon dumping into an oversized flue, i.e. flue temps that are too cool.

 

[JA600L]

I actually don't think Blaze Kings burn the lowest. They have an automatic control adjusting air supply. With my Ideal Steel I usually set it low and that's where the air stays if I'm doing a 24 hour cycle. Measuring btu output is hard. Most people assume a stove is producing heat when the top is at 300 degrees. My stove is still producing a lot of heat even after the stove top goes under 300. My house stays in the 70's and is comfortable for 24 hours +.

 

[Diabel]

From what I've read here, BK gets the longest burns of just about any EPA stove. This might mean that at some point in the burn cycle, even if the cat is active, the flue temps are the coolest of just about any EPA stove (assuming dry wood). If the cat is not burning all the particulate (and of course it won't burn 100% of it) the cool flue temps perhaps mean that little bit of remaining particulate is far more likely to condense inside the pipe?

I don't know if "filthy" is a word commonly used to describe BK stacks... seems like they are just slighltly dirtier/crustier. I know with the high flue temps of my downdraft stove I have NEVER had anthing other than light, fine brown powder. The shiny black crunchy stuff mentioned by the BK owners sounds like what I've seen in my fireplace or smoke dragon dumping into an oversized flue, i.e. flue temps that are too cool.

Yes, this makes sense. Thanks

 

[webby3650]

@BKVP is a wealth of combustion knowledge, maybe he will chime in here on this one?

 

[Diabel]

I suppose all these EPA stoves run at about 80% efficiency. So in the 20% of unburnt matter, in BK's case due to such low stack temp, it accumulates on the pipe. Without any visible smoke.

I remember reading posts from Backwoods Savage and the way he ran his Fireview. He claimed, not needing to clean the pipe for 4-5 seasons easily.

After installing my completely rebuilt encore 2550 back in early Nov. I have been going pretty much 24/7 (with few exceptions, couple warm spells and a vacation). My stack temps (internal probe) hover around 200 and 400*f (never exceeding 400).
I just pulled the cap off and if I get a tea cup of creo at the end of the season I will be surprised, 22' stack.

There must be something else going on with the BK technology (no visible smoke yet some black accumulation of creo).

 

[Babaganoosh]

I've run a cat stove (ideal steel) from October to now. April 5th. A few weeks ago I broke out my new sooteater and decided to give it a good clean. Well after cleaning the entire 13 feet I didn't even get a handful of accumulation from the chimney. I'm running double wall to the support box so it helps keep the gasses hot.