Burning cat stove without engaging the cat

[Kevin Weis]

Seems like these VC's can be run many ways with no one "right" way. My Intrepid right now has a cat temp of around 700, a stt of around 400, and a flue temp of about 225 (measured right above the stove). Very little smoke outside. For me it's all about the coal/fire placement in relation to the combuster airflow entrance more than anything else. This with the cat engaged.

 

[Eman85]

Seems like these VC's can be run many ways with no one "right" way. My Intrepid right now has a cat temp of around 700, a stt of around 400, and a flue temp of about 225 (measured right above the stove). Very little smoke outside. For me it's all about the coal/fire placement in relation to the combuster airflow entrance more than anything else. This with the cat engaged.

Looks like your STT to flue temps are inline with what I have with me not using the cat.
I'd like to see the temps from someone with a flexburn that doesn't have the cat.

 

[Ashful]

So if im reading this correctly.. your agreeing with me..

Maybe. I'm saying that it seems impossible the OP is seeing similar efficiency with bypass open and/or no cat installed, versus with a cat installed. Even a combustor with absolutely zero plating left would likely be better than none at all, if only for purely un-catalyzed reburn at 1100F, than running with none.

But I will admit I'm comparing VC Encore flue temps to BK flue temps, in trying to support this conclusion, which is really not valid. Both stoves set up perfectly, the BK will probably still see much lower flue temps or wider flue/STT ratios, than a VC Encore.

Whether or not the bypass is open is mostly irrelevant, once the cat has been removed. There may be small theoretical differences due to airflow direction, but for the most part, running with cat removed and bypass closed is probably not all that different from just running with bypass open, in stoves where the cat is located at top of firebox.

 

[Woodsplitter67]

For the record, and I have said this before, in my case the cat is only in my stove to keep the chimney cleaner. I too have never seen a difference in house temperatures with cat or without.
My stove just operates differently with/without it.

@Ashful .. this is the post that I was replying to.. no the OPs post

Im not sure what cat temperatures your seeing with blazeking.. but the temperatures on the stovepipe and back of the stove definitely increase.. My catalyst definitely is at 1400/1500 degrees sometimes and that smoke that is being burned as fuel is adding to some of the efficiency of the stove and getting additional heat out of it.

Im not saying that this is a super significant amount and this shoud be noted as a plus.. some heat is definitely gained.. When my cat is running at 1400 degrees my stovepipe is around 350ish.. outside on a double wall.. the back of the stove where the catalyst is .. ia also alot hotter.. Most of the cast is exposed to the heat from the cat and transferred out the rear of the stove. The back of the stove has a small piece of insulation board. The sides and half of the back are exposed to the higher heat and is transferred out..

 

[Ashful]

I think the reason our opinions seem to differ so much on this is that we're just running stoves of different design. The BK's have a heat shield directly behind the cat, which really seems to reflect a lot of the heat back at the cat, probably one of the things that helps them run so low and slow. This also presumably keeps flue temps down, when the bypass is closed. Conversely, the bypass is a straight hole up the chimney, right in the ceiling of the firebox, with no change in direction.

When I run in bypass, flue probe temps climb at an uncomfortably high rate, I'd not want to see how high they could climb. But after closing the bypass, they hold a tame 175F - 200F.

A downdraft cat stove, with the bypass in the back wall and flue gasses forced to go down thru a cat chamber before heading back skyward, is going to behave much differently with the cat removed.

 

[Woodsplitter67]

I think the reason our opinions seem to differ so much on this is that we're just running stoves of different design. The BK's have a heat shield directly behind the cat, which really seems to reflect a lot of the heat back at the cat, probably one of the things that helps them run so low and slow. This also presumably keeps flue temps down, when the bypass is closed. Conversely, the bypass is a straight hole up the chimney, right in the ceiling of the firebox, with no change in direction.

When I run in bypass, flue probe temps climb at an uncomfortably high rate, I'd not want to see how high they could climb. But after closing the bypass, they hold a tame 175F - 200F.

A downdraft cat stove, with the bypass in the back wall and flue gasses forced to go down thru a cat chamber before heading back skyward, is going to behave much differently with the cat removed.

As always.. an enjoyable conversation with you.. looking forward to your views in our next one also.. Blazeking was one.of my choices for stove brand.. I kinda wish I could try different stoves every 5 or so years..

I dont think its a matter of right or wrong.. and opinions vary.. your opinion to many here on this site matters.. including myself..

 

[sargeott]

I have trouble believing this. We have all seen our stovepipe probe temps drop from 700F in bypass to 300F with cat engaged, at the same burn rate. We can argue about the BTU content of all that hot air going up the pipe, in fact @ABMax24 can probably calculate for us. But no matter how you slice it, lower exhaust temperature at a given burn rate directly translates to more heat coming off the stove into your house. Simple Newton's Law of Conservation stuff, here.

I have never been able to get my flu temp (single wall pipe location 14 inches from stove exit using a surface thermometer) over 350degrees with my stove in bypass. This is with or without the cat installed.
I can run my stove in super hot mode, primary air at 100%, bypass on and it will eventually get STT over 600 and only then will I see flu temps about 350-400degrees max. Flu temps might go higher if I was willing to run the STT temps over 600, but I won't do that.
This tells me, that in my case, the catalyst isn't restricting heat flow enough to affect my flu temps. I know for sure it cleans the smoke with it installed.
I will agree that yes my flu temps drop when I engage the bypass lever (with or without the cat).
With where VC puts the catalyst in the Dauntless parallel to the fire box, so far down in the stove, the heat it creates is not making it's way to the flu thermometer location (about 46inches away). All of that heat the cat creates seems to be held inside my refractory area.

 

[Ashful]

As always.. an enjoyable conversation with you.. looking forward to your views in our next one also..

Ditto. I can always debate a point with you, even when we disagree, without it devolving into a pissing match. Always good and thoughtful conversation.

Blazeking was one.of my choices for stove brand.. I kinda wish I could try different stoves every 5 or so years..

Hopping on the @webby3650 plan? I think @bholler must be close to that, too. I did five stoves in 3-4 years, but then stalled when I reached a configuration that made me happy (two BK30's) in 2015.

I dont think its a matter of right or wrong.. and opinions vary.. your opinion to many here on this site matters.. including myself..

There are just so many variables, that what one of us sees on our setup is not always going to be a good prediction of what another can expect. Chimney height and type, wood quality and species, weather, house, operator, stove design and model... just too many variables to really predict anything with absolute certainty.

I have never been able to get my flu temp (single wall pipe location 14 inches from stove exit using a surface thermometer) over 350degrees with my stove in bypass. This is with or without the cat installed.

Yep, that roughly agrees with my numbers. I have always run two of the same stove, presently two Blaze King Ashford 30.1's, but previously two Jotul Firelight F12's. One of these setups has single wall pipe with a surface thermometer and the other has double wall pipe with a probe thermometer. I have always seen a roughly 2x difference in the temperatures between these rigs, with surface thermometer on single wall running about half that of probe thermometer on double wall, for similar operating conditions.

Others have done more direct and rigorous testing, with a flue probe and surface thermometer in the same single-wall pipe, recording steady-state measurements at the same time. They've been able to show with pretty good consistency that a surface probe reads about half of flue probe under most conditions. So, when I say 700F flue gas temperature, and you report 350F surface temperature, I believe we're really saying the same thing.

 

[Eman85]

Just to clarify my stove has a cat installed, I am not running with the cat removed, just not closing the damper.
Tonight just as an experiment I closed the damper to get a few readings. Stove has been running continuously for a few days now so all I did was reload and engage the cat.
Cat temps rose to 1000* STT was 575 and my flue thermometer was 350. I cut air back and the cat cruised at 1100 STT 600 and Flue 450. As the load burned down and cat dropped to 650 STT 475 Flue 325.
my flue temps are on my adapter with a magnetic thermometer so not totally accurate but from readings not too far off from non cat readings.

 

[webby3650]

Hopping on the @webby3650 plan? I think @bholler must be close to that, too. I did five stoves in 3-4 years, but then stalled when I reached a configuration that made me happy (two BK30's) in 2015.

I’ll be slowing down now. I installed an FPX Apex in the house we bought, it’s not likely I’ll change out a fire place. That’s why I had to build a test lab in the garage 😉

 

[Ashful]

Just to clarify my stove has a cat installed, I am not running with the cat removed, just not closing the damper.
Tonight just as an experiment I closed the damper to get a few readings. Stove has been running continuously for a few days now so all I did was reload and engage the cat.
Cat temps rose to 1000* STT was 575 and my flue thermometer was 350. I cut air back and the cat cruised at 1100 STT 600 and Flue 450. As the load burned down and cat dropped to 650 STT 475 Flue 325.
my flue temps are on my adapter with a magnetic thermometer so not totally accurate but from readings not too far off from non cat readings.

Are you able to move the thermometer up a bit, away from the stove collar? I think most of us read flue temperatures around 18" - 24" above stove collar, just to get away from the effect of the hot stove.

 

[Eman85]

Are you able to move the thermometer up a bit, away from the stove collar? I think most of us read flue temperatures around 18" - 24" above stove collar, just to get away from the effect of the hot stove.

Double wall attaches to the adapter so no room to move thermometer higher. I've considered drilling and installing a probe to monitor it like I do cat temps.


I started this thread as a spinoff from another thread about temps. @GrumpyDad was urged to start a thread about burning without the cat, but since I do it I figured I'd start the thread.

I've owned this stove since it was new, so over 35 years. I've burned it both ways in 2 different homes on 2 different style chimneys. With my current class A chimney I originally has single wall pipe and monitored with the magnetic thermometer at 18" above the collar and got similar readings, and yes the thermometer works and is accurate. Checked both with swapping with the STT thermometer and an IR gun.
I'm burning without the cat now just for the simplicity of it. I shut the cat off yesterday evening and I reloaded about 1/2 box before bed. I turned the air down to a little less than 1/2 open and went to sleep. Woke this morning and over 9 hours after last load I had a small pile of coals, heat never came on and the stove was still pretty hot. Hand full of small kindling and we're off again. I like simple and it doesn't get any simpler than that. Also FWIW my class is clean and doesn't get discolored at all. Only worry about controlling the stove is flue temps. The thermometer is easy to see and as long as we keep the needle below 12 o'clock which is 500* life is good. If it gets hot the paint on the stove pipe gives off an odor and STT goes over 650* so we don't go there. as long as the EPA doesn't sniff my pipe I guess I'm safe.

 

[Eman85]

@Ashful I just saw on the thread about small fires in large stoves some are seeing 1000* flue temps. Talk about heat going out the flue. Now I'm going to end up drilling my nice DW pipe just out of curiosity.

 

[Ashful]

@Ashful I just saw on the thread about small fires in large stoves some are seeing 1000* flue temps. Talk about heat going out the flue. Now I'm going to end up drilling my nice DW pipe just out of curiosity.

You won't regret it! Just get one of the Condar Flue-Gard units that stays in with a magnet. Insert until magnet grabs, and then easily pull out for each sweeping. Simple, genius design.

 

[Woodsplitter67]

I started this thread as a spinoff from another thread about temps. @GrumpyDad was urged to start a thread about burning without the cat, but since I do it I figured I'd start the thread.

Dont take this the wrong way.. Im enjoying your thread.. and glad you posted this about your stove

So actually.. in the thread that I replied to.. his question was.. with the temperature swings that we see.. why not burn without the catalyst in.. like he does. His stove and setup are different from yours, and he also knows the answers to the question hes asking..

The mods have indicated that some of the information that we give gets buried in these threads and want the newer people to be able to look it up for access. Which is why the request in the original thread..

GrumpyDad likes to burn without the catalyst. Thats fine for him.. he cant figure out how to burn with it and his poor setup gives him difficulty with it..

The issue being... with these newer stoves and new people get the wrong idea of that is how it should be done. When in fact its not the best burning practice at all.

Many of the newer people struggle.. for a number of reasons.. poor wood and poor setup as well as other issues. Removing the catalyst in many cases, I feel just masks the issues they are having leading to more issues.

In fact if you read back to last year.. this certain member installed his stove about September and by November had his first chimney fire burning without the catalyst.. a new hearth record BTW... and complained about the smell of creosote and it dripping down the pipe.

We certainly dont want to give new people the wrong impression. You have had your stove for many years and your experienced.. like others here ..and know how to used the cat and non cat.. but remember.. not everyone is in our boat.

This is exactly why I caution people who read these threads..

 

[Eman85]

This why I make the disclaimer about how old my stove is, how long I've had it and also the fact I cut and season my own wood and also clean my own chimney. I'm also the guy that installed the chimney. I'm also the guy that would have to rebuild my house if I burn it down. I'm also the guy whose wife can light the stove and burn a fire for weeks continuously as long as she doesn't have to fool with the cat. She also likes smaller splits of wood so I split smaller.

 

[Kevin Weis]

Just to clarify my stove has a cat installed, I am not running with the cat removed, just not closing the damper.
Tonight just as an experiment I closed the damper to get a few readings. Stove has been running continuously for a few days now so all I did was reload and engage the cat.
Cat temps rose to 1000* STT was 575 and my flue thermometer was 350. I cut air back and the cat cruised at 1100 STT 600 and Flue 450. As the load burned down and cat dropped to 650 STT 475 Flue 325.
my flue temps are on my adapter with a magnetic thermometer so not totally accurate but from readings not too far off from non cat readings.

So then your running your stove as an enclosed fireplace. Like an old Jotul Fireplace Stove #3 I saw at a sale today. Even with the fire controlled, burning that way routinely would think it a creosote maker for sure.

 

[sargeott]

So then your running your stove as an enclosed fireplace. Like an old Jotul Fireplace Stove #3 I saw at a sale today. Even with the fire controlled, burning that way routinely would think it a creosote maker for sure.

That's an expensive nonefficient fireplace if he is.
These things need heat to stay inside the firebox to be worth owning.

 

[Ashful]

So then your running your stove as an enclosed fireplace. Like an old Jotul Fireplace Stove #3 I saw at a sale today. Even with the fire controlled, burning that way routinely would think it a creosote maker for sure.

Not terrible, if burned hot. Fireplaces make some creosote, sure... but really not as terrible as you'd assume based on experience with stoves alone. With a 6" liner, temperature and velocity are better than an open fireplace, it's really only by limiting inlet air that folks get themselves in trouble on older stoves without secondary burn.

 

[Kevin Weis]

Not terrible, if burned hot. Fireplaces make some creosote, sure... but really not as terrible as you'd assume based on experience with stoves alone. With a 6" liner, temperature and velocity are better than an open fireplace, it's really only by limiting inlet air that folks get themselves in trouble on older stoves without secondary burn.

He's running it with the bypass open so no secondary burn. So maybe not so bad as long as he keeps enough air going g to it?

 

[Eman85]

I turn the air down, I can get 10 hour burns. Yes it smokes, yes it will create creosote if I burn like this. I have burned stoves for decades from home made stoves to this one and others in between. Woodstoves all worked like this years ago and they kept refining the air intake and making the stoves airtight so you had more control. Cars didn't have seatbelts air bags or antilock brakes, some of my cars had no AC no power windows some had no power brakes and no power steering. I've been known to run with scissors.

 

[Ashful]

I turn the air down, I can get 10 hour burns. Yes it smokes, yes it will create creosote if I burn like this. I have burned stoves for decades from home made stoves to this one and others in between. Woodstoves all worked like this years ago and they kept refining the air intake and making the stoves airtight so you had more control. Cars didn't have seatbelts air bags or antilock brakes, some of my cars had no AC no power windows some had no power brakes and no power steering. I've been known to run with scissors.

I'll bet you even cut the tag off a mattress once. Rebel!

 

[Wisco Shepherd]

Dont take this the wrong way.. Im enjoying your thread.. and glad you posted this about your stove

So actually.. in the thread that I replied to.. his question was.. with the temperature swings that we see.. why not burn without the catalyst in.. like he does. His stove and setup are different from yours, and he also knows the answers to the question hes asking..

The mods have indicated that some of the information that we give gets buried in these threads and want the newer people to be able to look it up for access. Which is why the request in the original thread..

GrumpyDad likes to burn without the catalyst. Thats fine for him.. he cant figure out how to burn with it and his poor setup gives him difficulty with it..

The issue being... with these newer stoves and new people get the wrong idea of that is how it should be done. When in fact its not the best burning practice at all.

Many of the newer people struggle.. for a number of reasons.. poor wood and poor setup as well as other issues. Removing the catalyst in many cases, I feel just masks the issues they are having leading to more issues.

In fact if you read back to last year.. this certain member installed his stove about September and by November had his first chimney fire burning without the catalyst.. a new hearth record BTW... and complained about the smell of creosote and it dripping down the pipe.

We certainly dont want to give new people the wrong impression. You have had your stove for many years and your experienced.. like others here ..and know how to used the cat and non cat.. but remember.. not everyone is in our boat.

This is exactly why I caution people who read these threads..

As a relatively new burner these threads are interesting for sure. I have a cat stove (Kuma Aspen LE) and burn with the catalyst. The only deviation I have made from manufacturers recommendation on burning is cutting my air sooner as Kuma wants you to burn air wide open until 20-30 minutes after engaging the catalyst and I have found this to be a bit excessive.

While I enjoy these threads as "brain food" I take the experiences with a grain of salt and will wait to have a few more years of experience before I throw my cowboy hat on.

 

[sargeott]

As a relatively new burner these threads are interesting for sure. I have a cat stove (Kuma Aspen LE) and burn with the catalyst. The only deviation I have made from manufacturers recommendation on burning is cutting my air sooner as Kuma wants you to burn air wide open until 20-30 minutes after engaging the catalyst and I have found this to be a bit excessive.

While I enjoy these threads as "brain food" I take the experiences with a grain of salt and will wait to have a few more years of experience before I throw my cowboy hat on.

I wear mine every day. But, It's part of my lifestyle. Thanks for posting your experience.

 

[Eman85]

I understand many people who are new to burning wood come on these forums. Burning wood has been going on since man found fire. These new stoves are no different than driving or working on a new car with all of the gizmos and gadgets and the idiot proof safety features. It's a lot easier if you understand the basics and how to operate without the gizmos so you can understand the gizmos. Sometimes there's no replacement for common sense and the KISS method of operation.
I don't wear a hat.