2023/24 VC Temperature discussion thread

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So I had one of those WTF moments last night.. I had cleaned to stove and swapped the steel cat to a ceramic cat.. ran if for a couple days.. last night did my normal reload for my overnight burn.. loaded the stove to the gills.. cat was something like 1000.. I immediately cut the air back all the way.. sat and watched football.. the whole time the cat was like 1430.. which is pretty normal.. all the suddenit started to climb.. and man was it drafting HARD.. cat went up to 1650.. the box turned into a flaming mess with an a$$ load of secondary combustion in the box.. it only stayed that way for 5/10 minutes and immediately dropped to the low 1500s.. but man was that a head scratcher.. I was looking at my stove and saying.. who the fOck are you..
Welcome to the WTF club.... we have a lot of members. This happens to me regularly, every couple days or so.

Lately my cat temps have been cruising at 1600 with peaks up to 1670 or so, even with red oak and 20% air. I follow my same process that was working well a month ago and running at 1400 - 1500. Only thing I can think of that changed is increased draft due to lower outside temps. Maybe the wood is a bit drier as I am now pulling from the middle of my woodshed?

IDK.... cat alarm is now set to 1700 so I can get some sleep.
 
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So.... when my ash trees started dying off in numbers a few years ago I started doing some research and learned about the beetle..... I even sat through some online forestry lectures. What I learned was the beetle does not bore into the center of the tree, it focuses in the outer layer of soft wood (I think it is called the cambrium). The adult beetle lays eggs in there and when the larva hatch they start boring their way around that layer, not into the heartwood. Ash trees are unique in the way they feed the canopy in that all the sap runs through the cambrium which is a very think layer. Once the beetles have worked their way around the circumference of the tree it is now starved, there is no path for water to go from the root system to the foliage and it dies.

I have seen this on many of my trees, you see a bunch of holes in the bark, 1/4" = 3/8" diameter but if you peel the bark off you see all these tracks in the outer layer of softwood.

View attachment 323418

My point: The beetle does not bore through the heartwood and leave it porous, so that is not what is causing the effect.

It may be some other side effect of the beetle damage though..... maybe the wood is drier because it has been standing dead or partially dead for a few years?

Very interesting question posed by @U235 .... would love to hear from someone who knows, has ash always been this way? Or just since the beetle?

What if find most interesting is my Ash loads do not seem to burn quicker or more flame intense as far as I can tell. It burns great and leaves lots of hot coals, it just results in high cat temps....

As for pine: We all know why that goes up quick, pitch... right?
I used to burn ash, before the beetles arrived. It was always a faster more intense burn than Oak or Hickory, somewhat similar to Sugar Maple in my experience. The stove I was using back then was equipped with secondary burners and they really glowed red when I ran Ash through it on same air setting as Oak or Hickory. My solution was to mix Walnut with Ash and the combo burned similar to the others. Eventually I fell out of favor with Walnut as it rots faster than I can get it split, so I also no longer burn Ash but mostly because it's no longer available here in my part of Ohio.
 
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So I don’t know if this counts as an “ah ha” or “d’oh” moment but… I’ve noticed if I run my flue temp up a little higher before going to cat mode I’m getting less (no) back puffs. My rationale is I can’t get above a certain flue temp until all the moisture is evaporated out of the wood (or at least a certain percentage of it). Stt of 400, 509, 550…doesn’t seem to make a difference on my setup but taking flue temp from 300 to 350 before I engage the cat has made a huge difference. ***note flue temp on my stove is actually skin temp on single wall transition custom built out of some heavy sheet metal***. So actual flue temp is definitely higher than that. I’m just saying I see kind of a flat spot in my flue temp trend and once I cross that and start climbing again my stove is good to go to cat mode.

After cat mode engaged run cat up to 1000 before shutting down air like always.
I have been playing with running my stove hotter and longer before engaging the CAT to see if it stops puff backs. Yes it does, and actually gets no hotter at flue base than starting cooler and letting it build. Cleaner door glass as well.
 
Last night was another flaming mess.. switched bak to the steel cat this afternoon .. just relit the stove
What are you hoping that will achieve?
I know the steel cats are supposed to be less volitile....
 
What are you hoping that will achieve?
I know the steel cats are supposed to be less volitile....
My stove seems to run much better with the steel cat. Temperatures stay in the happy zone. Last night when I went to bed the cat temperature was wapping 1435 degrees.. monday night when I wet to bed the cat had gone up to 1670.. which was higher then the 1650 fro. the night before
 
Finally had her take off on me yesterday. Scared the hell out of me.

I was working from home so I had been burning all day. Once the stove is up and running and the cat is active I typically feed 3 or so splits at a time (small stove.) Yesterday she was running fine all day CAT was in the 700-800's for the day and STT was around 550. Got a lot of good heat and I was thinking that I had it all figured out.

About 5:15 it was time for a reload. A good thick bed of coals, not sure what STT was but my CAT was in the low 600's. I decided that because it had been running great all day that I'd try to really load her up for the first time ever. I packed it almost to the top, more wood than I'd ever put in. I let it get lit for 2-3 minutes and closed the damper. The CAT was already lit off so I figured I'd be good to go. About 1/2 an hour later I checked on it and my STT was only 300 while the CAT was in the 800's. I let it ride for a bit and when the cat hit 950 I cut the air back to about 25% open. The CAT temp kept slowly creeping up. Once it hit 1200 I closed that air all the way. It kept creeping up. Eventually it hit 1500. I opened the top to rearrange the wood in the firebox and get anything away from the back. Once l closed it back up the CAT took off. It ended up coming close to 1800. I was eventually able to cool it down enough by opening the damper and letting the heat go up the chimney for a few minutes, then closing it back down. I had to do this 2-3 times before it decided to settle around 1450. Once the CAT settled I checked the STT and that was around 750. I brought in a box fan and pointed it at the stove and let it run until it was back in the 600's. I was checking the stove pipe about 8 inches out of the back of the stove and that was 758 I think at the highest I saw it. That means what like 1500 in the pipe?

Needless to say I'll stick with 2-3 splits at a time from here on out.
 
Finally had her take off on me yesterday. Scared the hell out of me.

I was working from home so I had been burning all day. Once the stove is up and running and the cat is active I typically feed 3 or so splits at a time (small stove.) Yesterday she was running fine all day CAT was in the 700-800's for the day and STT was around 550. Got a lot of good heat and I was thinking that I had it all figured out.

About 5:15 it was time for a reload. A good thick bed of coals, not sure what STT was but my CAT was in the low 600's. I decided that because it had been running great all day that I'd try to really load her up for the first time ever. I packed it almost to the top, more wood than I'd ever put in. I let it get lit for 2-3 minutes and closed the damper. The CAT was already lit off so I figured I'd be good to go. About 1/2 an hour later I checked on it and my STT was only 300 while the CAT was in the 800's. I let it ride for a bit and when the cat hit 950 I cut the air back to about 25% open. The CAT temp kept slowly creeping up. Once it hit 1200 I closed that air all the way. It kept creeping up. Eventually it hit 1500. I opened the top to rearrange the wood in the firebox and get anything away from the back. Once l closed it back up the CAT took off. It ended up coming close to 1800. I was eventually able to cool it down enough by opening the damper and letting the heat go up the chimney for a few minutes, then closing it back down. I had to do this 2-3 times before it decided to settle around 1450. Once the CAT settled I checked the STT and that was around 750. I brought in a box fan and pointed it at the stove and let it run until it was back in the 600's. I was checking the stove pipe about 8 inches out of the back of the stove and that was 758 I think at the highest I saw it. That means what like 1500 in the pipe?

Needless to say I'll stick with 2-3 splits at a time from here on out.
It sounds like you had a smoldering mess in the fire box with the STT that low and the cat that high. This is why I have been leaning towards burning a little longer and higher upfront like @Sticker to make sure I have a good fire in the box. So far it has worked pretty well but that is also a fine line.
 
It sounds like you had a smoldering mess in the fire box with the STT that low and the cat that high. This is why I have been leaning towards burning a little longer and higher upfront like @Sticker to make sure I have a good fire in the box. So far it has worked pretty well but that is also a fine line.
Typically with 2-3 splits I reload while the cat is still active and shut the damper immediately. The cat will get up in the 800's and settle in the 700's for the rest of the burn.

While the cat temp was climbing at one point I opened the air up to get more flames in the box, but the cat temp just went up even faster at that point. There was a good hour or so that I was dealing with the stove.
 
Question : how big of splits are you all using in your stoves?
I seem to have more luck with consistent temperatures without inexplicable temp swings, cat always staying in the sweet spot, with slightly larger medium pieces or I guess what people would consider large pieces. So I guess like 4x4 inches or maybe even bigger?
I did have a 1600 degree cat temp spike recently because I tossed in a few mediums one morning and left the air control at around 80%. Once I backed the air down, that cat screamed upwards for awhile before settling back down.
 
Stove is finally cold! The artic blast is over and now it's going to be in the 60's during the day and 50's at night.
Just my observations from this cold snap. First off my wood is mixed hardwoods of all types, this stack is large and an accumulation of trees cut and down wood from around the property. Been cut split and stacked for years and the splits are small, 4" and less as a lot of it is large branches and all split nothing left in the round. My cat was more controllable this year as I cut the air back sooner, 1000 to 1100 and the air was back to 10%. If in the burn at that air rate it started to get over 1400 and rising I cut the air all of the way and the cat settled and was fine. At 1430 or so the whooshing in the back of the stove started, didn't like that. On my stove with the cat temps 1000+ and the air cut back STT is in the 350-400 range. I don't get higher STT unless I open the air which I don't do until the cat has risen, settled and then dropped into the 800's or so then I can open the air. On overnight burns I time it so the cat does it's thing and settles into the 1200 range and I feel comfortable going to bed, I have the alarm set at 1700 and never had it go off. I use the max recall and check it and it's usually never higher than I saw it before I go to bed. Mornings the STT is 300 or so and the cat is high 300's to 500 and I open the air all of the way. Cat rises sometimes to 1000 and STT goes to 500's or so burning off what's left. I can let that burn like that for an hour or 2 before reloading.
It would be nice to get more heat from the stove in cat mode, but I can only do that if I'm around to open the air a few hours into the burn. If I want pure heat from the stove I can do that burning without using the cat. I've never aborted the burn and opened the damper when the cat started rising, closing the air takes a little time but has always reined it in.
 
Finally had her take off on me yesterday. Scared the hell out of me.

I was working from home so I had been burning all day. Once the stove is up and running and the cat is active I typically feed 3 or so splits at a time (small stove.) Yesterday she was running fine all day CAT was in the 700-800's for the day and STT was around 550. Got a lot of good heat and I was thinking that I had it all figured out.

About 5:15 it was time for a reload. A good thick bed of coals, not sure what STT was but my CAT was in the low 600's. I decided that because it had been running great all day that I'd try to really load her up for the first time ever. I packed it almost to the top, more wood than I'd ever put in. I let it get lit for 2-3 minutes and closed the damper. The CAT was already lit off so I figured I'd be good to go. About 1/2 an hour later I checked on it and my STT was only 300 while the CAT was in the 800's. I let it ride for a bit and when the cat hit 950 I cut the air back to about 25% open. The CAT temp kept slowly creeping up. Once it hit 1200 I closed that air all the way. It kept creeping up. Eventually it hit 1500. I opened the top to rearrange the wood in the firebox and get anything away from the back. Once l closed it back up the CAT took off. It ended up coming close to 1800. I was eventually able to cool it down enough by opening the damper and letting the heat go up the chimney for a few minutes, then closing it back down. I had to do this 2-3 times before it decided to settle around 1450. Once the CAT settled I checked the STT and that was around 750. I brought in a box fan and pointed it at the stove and let it run until it was back in the 600's. I was checking the stove pipe about 8 inches out of the back of the stove and that was 758 I think at the highest I saw it. That means what like 1500 in the pipe?

Needless to say I'll stick with 2-3 splits at a time from here on out.
I think you figured out the key information without realizing it. Great breakdown btw.
Here is what I think:
When you packed the stove full with the cat inside operation zone and a healthy bead of coals, all of that wood starts to bake and off gas. It's not burning except mabey the bottom layer and there is so much wood in the box, the flames don't get all the way to the top of the stove for combustion. The wood then absorbes the heat in the box preventing it from reaching the stove top (this explains the lower STT).
Your wood then is throwing a massive ammount of smoke and gasses into the 2ndary combustion chamber and your cat is rapidly trying to eat it all spiking the cat temps. The coals are keeping the smoke HOOOOT.

Now, how to fix and or prevent/manage that..... IDK
I have never had this problem. My draft has never gotten so strong where it sucks all of that smoke causing a runaway. Usually my stove top temp is directly related to my primary air control in the Duantless & how much wood is in my stove. It will always drop for me after a reload, then creeps back up over time.
Additionally, my flu temps never get over 300f unless my bypass is open regardless of the wood load and air control settings.
 
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Finally had her take off on me yesterday. Scared the hell out of me.

I was working from home so I had been burning all day. Once the stove is up and running and the cat is active I typically feed 3 or so splits at a time (small stove.) Yesterday she was running fine all day CAT was in the 700-800's for the day and STT was around 550. Got a lot of good heat and I was thinking that I had it all figured out.

About 5:15 it was time for a reload. A good thick bed of coals, not sure what STT was but my CAT was in the low 600's. I decided that because it had been running great all day that I'd try to really load her up for the first time ever. I packed it almost to the top, more wood than I'd ever put in. I let it get lit for 2-3 minutes and closed the damper. The CAT was already lit off so I figured I'd be good to go. About 1/2 an hour later I checked on it and my STT was only 300 while the CAT was in the 800's. I let it ride for a bit and when the cat hit 950 I cut the air back to about 25% open. The CAT temp kept slowly creeping up. Once it hit 1200 I closed that air all the way. It kept creeping up. Eventually it hit 1500. I opened the top to rearrange the wood in the firebox and get anything away from the back. Once l closed it back up the CAT took off. It ended up coming close to 1800. I was eventually able to cool it down enough by opening the damper and letting the heat go up the chimney for a few minutes, then closing it back down. I had to do this 2-3 times before it decided to settle around 1450. Once the CAT settled I checked the STT and that was around 750. I brought in a box fan and pointed it at the stove and let it run until it was back in the 600's. I was checking the stove pipe about 8 inches out of the back of the stove and that was 758 I think at the highest I saw it. That means what like 1500 in the pipe?

Needless to say I'll stick with 2-3 splits at a time from here on out.
Do you think this happened because you did a full load on a large coal bed? Maybe since the stove and cat is already hot a full load can be too much fuel for the cat especially if the air is set too low and sending lots of smoke into that secondary burn chamber?

I think just about any stove has a better chance of overfiring with a large coal bed or hot reloads. I try and keep my coal bed to a minimum when I’m on a 8 or 12 hour reload schedule. Sometimes I’ll rake the coals and open the air full for awhile til it’s down to where I like it. Other times when it’s really cold out I don’t worry about the coal bed and just load a half load and burn a little hotter and load more often like you stated.
 
Finally had her take off on me yesterday. Scared the hell out of me.

I was working from home so I had been burning all day. Once the stove is up and running and the cat is active I typically feed 3 or so splits at a time (small stove.) Yesterday she was running fine all day CAT was in the 700-800's for the day and STT was around 550. Got a lot of good heat and I was thinking that I had it all figured out.

About 5:15 it was time for a reload. A good thick bed of coals, not sure what STT was but my CAT was in the low 600's. I decided that because it had been running great all day that I'd try to really load her up for the first time ever. I packed it almost to the top, more wood than I'd ever put in. I let it get lit for 2-3 minutes and closed the damper. The CAT was already lit off so I figured I'd be good to go. About 1/2 an hour later I checked on it and my STT was only 300 while the CAT was in the 800's. I let it ride for a bit and when the cat hit 950 I cut the air back to about 25% open. The CAT temp kept slowly creeping up. Once it hit 1200 I closed that air all the way. It kept creeping up. Eventually it hit 1500. I opened the top to rearrange the wood in the firebox and get anything away from the back. Once l closed it back up the CAT took off. It ended up coming close to 1800. I was eventually able to cool it down enough by opening the damper and letting the heat go up the chimney for a few minutes, then closing it back down. I had to do this 2-3 times before it decided to settle around 1450. Once the CAT settled I checked the STT and that was around 750. I brought in a box fan and pointed it at the stove and let it run until it was back in the 600's. I was checking the stove pipe about 8 inches out of the back of the stove and that was 758 I think at the highest I saw it. That means what like 1500 in the pipe?

Needless to say I'll stick with 2-3 splits at a time from here on out.
Just my experience when I reload over a real hot large coal bed and pack it to the top I cut the air back as soon as I close the damper. This cold snap I had one time where I didn't and the cat started to take off but I shut the air and rode it out cat quit at 1560.
Not familiar with your stove but it brings us back to secondary air intake questions. My stove has a secondary air intake flap on the back that is thermostatically controlled. It closes after first warmup and will open back as the cat gets to 1600.
 
Just my experience when I reload over a real hot large coal bed and pack it to the top I cut the air back as soon as I close the damper. This cold snap I had one time where I didn't and the cat started to take off but I shut the air and rode it out cat quit at 1560.
Not familiar with your stove but it brings us back to secondary air intake questions. My stove has a secondary air intake flap on the back that is thermostatically controlled. It closes after first warmup and will open back as the cat gets to 1600.
I wish I could see my secondary intake better. I would love to see when it decides to open and when it decides to be closed.
 
I think this needs its own thread.. General discussion of stove temperature performance

@arnermd needs place to show the fancy graphs he makes..
Woodsplitter,
I have scanned through the 22 pages of the temperature thread and would love to find one (perhaps it should be pinned if possible) description of how to load and run a VC Cat stove. Even if it is a general best practices outline. I know it all depends on many variables, but the owners manual is just not as granular as what people need in real life. Also....wondering which thermometer would be recommended for the both SST and catalyst. I have seen many mentioned here. I do not need logging and battery operated would be best for me as no outlet available. These threads are a lot to digest and there is a lot of abbreviation and jargon. I could post a new thread question and I don't know what the moderators prefer....long threads or new posts with specific questions. Thank you for the help!
 
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Woodsplitter,
I have scanned through the 22 pages of the temperature thread and would love to find one (perhaps it should be pinned if possible) description of how to load and run a VC Cat stove. Even if it is a general best practices outline. I know it all depends on many variables, but the owners manual is just not as granular as what people need in real life. Also....wondering which thermometer would be recommended for the both SST and catalyst. I have seen many mentioned here. I do not need logging and battery operated would be best for me as no outlet available. These threads are a lot to digest and there is a lot of abbreviation and jargon. I could post a new thread question and I don't know what the moderators prefer....long threads or new posts with specific questions. Thank you for the help!

look at different burning techniques. on the main VC page.. 2nd page back
 
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look at different burning techniques. on the main VC page.. 2nd page back

Screenshot_20240124-151957_Samsung Internet.jpg
 
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My stove seems to run much better with the steel cat. Temperatures stay in the happy zone. Last night when I went to bed the cat temperature was wapping 1435 degrees.. monday night when I wet to bed the cat had gone up to 1670.. which was higher then the 1650 fro. the night before
The billion dollar question..... Why? What changed? Maybe it was the ceramic cat.... anything else?
 
I have been playing with running my stove hotter and longer before engaging the CAT to see if it stops puff backs. Yes it does, and actually gets no hotter at flue base than starting cooler and letting it build. Cleaner door glass as well.
More details please..... when do you engage the cat? At what temps? What temp are you triggering off of.
 
I wish I could see my secondary intake better. I would love to see when it decides to open and when it decides to be closed.
your secondary air is always full open, nothing to see. the 2n1 designs do not have active secondary air control.
 
Finally had her take off on me yesterday. Scared the hell out of me.

I was working from home so I had been burning all day. Once the stove is up and running and the cat is active I typically feed 3 or so splits at a time (small stove.) Yesterday she was running fine all day CAT was in the 700-800's for the day and STT was around 550. Got a lot of good heat and I was thinking that I had it all figured out.

About 5:15 it was time for a reload. A good thick bed of coals, not sure what STT was but my CAT was in the low 600's. I decided that because it had been running great all day that I'd try to really load her up for the first time ever. I packed it almost to the top, more wood than I'd ever put in. I let it get lit for 2-3 minutes and closed the damper. The CAT was already lit off so I figured I'd be good to go. About 1/2 an hour later I checked on it and my STT was only 300 while the CAT was in the 800's. I let it ride for a bit and when the cat hit 950 I cut the air back to about 25% open. The CAT temp kept slowly creeping up. Once it hit 1200 I closed that air all the way. It kept creeping up. Eventually it hit 1500. I opened the top to rearrange the wood in the firebox and get anything away from the back. Once l closed it back up the CAT took off. It ended up coming close to 1800. I was eventually able to cool it down enough by opening the damper and letting the heat go up the chimney for a few minutes, then closing it back down. I had to do this 2-3 times before it decided to settle around 1450. Once the CAT settled I checked the STT and that was around 750. I brought in a box fan and pointed it at the stove and let it run until it was back in the 600's. I was checking the stove pipe about 8 inches out of the back of the stove and that was 758 I think at the highest I saw it. That means what like 1500 in the pipe?

Needless to say I'll stick with 2-3 splits at a time from here on out.

I dont ever open up the stove. I have Never altered the course of it neither. I 100% let the stove do its thing. This is just my experience... and I haven't had alot of them either..

Most recently my cat temperature climbed to 1670. It never hangs at a peak temperature like that long. maybe 5/10 minutes.. then drops down and even it stayed there for 15 or so.. nothing really happens.

The only thing actually happening is killing the life of the cat. Me personally I don't see Crazy stovepipe temperatures in my double wall pipe.. Iv had the stove apart and the back of the stove is protected with insulation board so its not like the stove is going to crack

I just let it run its course never lasts long never any damage to the stove itself or stovepipe

Im definitely open to this discussion of why people get alarmed regarding this besides the damage to the cat what else could be a issue.

I know its unsettling and we want all of our temperatures to stay 1200 degrees, but why not just let it run its course

@arnermd whatnare your thoughts you probably have the most experience in this
 
The billion dollar question..... Why? What changed? Maybe it was the ceramic cat.... anything else?

The only chang was that I swapped back to the ceramic cat.. I didn't vacuum it or even do a full cleanout.. I just ranked some ash.. emptied the pan and relite the stove.. and bag.. nothing be issues for the 2 nights I had it in..

Last night I put the steel cat back in.. same thing.. I just raked the ash but didn't have to empty the pan.

I did my normal overnight burn.. the cat temperature never went above 1440 last night.. it Peaked somewhere in the 1430s and then steadily dropped

Ill be sticking with the steel cat for the rest of the winter until shoulder season starts.. then maybe ill put the ceramic back in
 
Woodsplitter,
I have scanned through the 22 pages of the temperature thread and would love to find one (perhaps it should be pinned if possible) description of how to load and run a VC Cat stove. Even if it is a general best practices outline. I know it all depends on many variables, but the owners manual is just not as granular as what people need in real life. Also....wondering which thermometer would be recommended for the both SST and catalyst. I have seen many mentioned here. I do not need logging and battery operated would be best for me as no outlet available. These threads are a lot to digest and there is a lot of abbreviation and jargon. I could post a new thread question and I don't know what the moderators prefer....long threads or new posts with specific questions. Thank you for the help!
I'll answer this as I've used battery and 110v style. Auber lists thermocouple's with mini connector ends on them. They have a magnetic one for STT, a probe style for flue temps with a bracket for attachment and a long high temp one for the catalyst. I have a few battery powered meters that do strictly temperature that I use for auto exhaust gas and also for my smoker, plenty for sale on ebay. If you have a digital multimeter many of them have the spot to plug in the mini connector thermocouple and will read temperature.
 
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I dont ever open up the stove. I have Never altered the course of it neither. I 100% let the stove do its thing. This is just my experience... and I haven't had alot of them either..

Most recently my cat temperature climbed to 1670. It never hangs at a peak temperature like that long. maybe 5/10 minutes.. then drops down and even it stayed there for 15 or so.. nothing really happens.

The only thing actually happening is killing the life of the cat. Me personally I don't see Crazy stovepipe temperatures in my double wall pipe.. Iv had the stove apart and the back of the stove is protected with insulation board so its not like the stove is going to crack

I just let it run its course never lasts long never any damage to the stove itself or stovepipe

Im definitely open to this discussion of why people get alarmed regarding this besides the damage to the cat what else could be a issue.

I know its unsettling and we want all of our temperatures to stay 1200 degrees, but why not just let it run its course

@arnermd whatnare your thoughts you probably have the most experience in this
This is why I don't monitor my Cat temps. I just don't care. The stupid thing is going to do whatever it does.
The sTT tells me my heat output
the Flu temp tells me when I should have maximum available draft
Those two tell me when to take it out of bypass.
 
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