2023/24 VC Temperature discussion thread

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I just reloaded over a small bed of coals, packed the box and let it run with the air open and the damper open. good flame in the box cat dropped to low 500's and I closed the damper. Cat rose to 1000 and I closed air to 10%, cat temps slowed and rose a little then dropped. I checked back on it and the cat temps were rising steadily at 1450 I shut the air and the cat rose a little more then dropped is steady now at 1411. Outside temp is a balmy 18*.
 
I was thinking something similar. On this run I ran it with more air, thinking was I would get more primary burn and maybe less secondary...
  • Very similar load to last time, 5 med splits all ash, minimal bark
  • Engaged the cat at flue gas = 500
  • Cut air back to 60% at cat = 500 (much lower than normal for me)
  • At 16:36 the flue gas rocketed to 1400.... There was no intervention from me. This happened incredibly fast.
    • The only thing I noticed was some logs settling as I heard them drop around this time.
    • Got that plasticy smell in the house........ Stack was hot!
  • Cat ground higher peaking at 1671.....
  • Stove was throwing a lot of heat, too much. 87F in my room with the stove.
Conclusion: Increasing air setting did not affect peak cat temps and over heated the house....

View attachment 323003
Who needs and logic? Not the VC Defiant!

Those crazy quick and high spikes in the flue happened to me the first time I did a full load of ash. I scared me pretty good. That's why I basically aborted that burn. Wasn't sure how high those spike were going to get.
 
Here's my 1 year old steel cat from VC. Pretty sad looking but she still works. I just installed a ceramic cat from Condar. Time will tell if the stove runs any better. My cat temps often spike over 1600 degrees 2-3 hours into a burn with the steel cat. . I found that in my VC Dutchwest the ceramic cats stayed at a more constant temp.
IMG_0834.jpeg
 
Well I just did a full clean out after burning 24x7 for over a month straight. Outside temps finally got above 35f.
Cat was 1/4 plugged with fly ash.I'm sure this was my fault. The cat condition looks fine. No warping or breakage.

The last week we had such cold outside temps I kept the stove completly topped off with fresh wood. I tried to keep the stt over 500f all the time and because of that I had a solid 6-8inch ash base in the bottom. I never let it burn down enough to prod the bottom of the stove to let it settle into the ash pan. This could have been my issue in keeping the stove super hot IDK.
I was afraid to let the STT temp settle below 450 because we needed the heat so so badly after losing power last friday night into sunday am. The outside temps last fri-monday never rose above 8 degrees and this old cabin has terrible insulation for those temps. I hate ice storms.


Tomorrorow If the temps get back above freezing I can let the stove cool back down and inspect my chimney for build up and flow. It's been a solid month since I last cleaned it out and have been burning with the cat engaged non- stop. We cooked about 1 cord of wood in 30 days.
I will try to take pictures if I remember to.
This is the most I have used this stove since we bought it.
 
I'm still burning 24/7, got up to 32 today but it's supposed to really drop tonight and over the next 2 days. I've been able to run on 2 loads for 24 hours. This morning the stove decided it wanted to run a little. I packed it and cut the air back to 10% like I'd been doing and it reacted just like it had been. When it started climbing I was a little late in cutting it all the way back and it went to 1560 before it stopped and settled back down. When it gets past about 1450 it really sets up a roar in the back of the stove, I don't like that sound. Once it trended down it was fine and settled in the 1000's and cruised.
 
Right now the stoves drafting harder then average.. I have the air up because I need more heat.. my wife did the overnight burn.. I was low on stove temp this morning.. basically had to to a cold start and there was a chill in the house.. cat temperature is a wapping 1531 and holding steady
 
I'm still burning 24/7, got up to 32 today but it's supposed to really drop tonight and over the next 2 days. I've been able to run on 2 loads for 24 hours. This morning the stove decided it wanted to run a little. I packed it and cut the air back to 10% like I'd been doing and it reacted just like it had been. When it started climbing I was a little late in cutting it all the way back and it went to 1560 before it stopped and settled back down. When it gets past about 1450 it really sets up a roar in the back of the stove, I don't like that sound. Once it trended down it was fine and settled in the 1000's and cruised.
What kind of wood are you burning?
 
Now that I'm exclusively ash, I can't get a decent 8 hour burn. I am going to have to find a way to source some oak or locust to burn with all the ash I have. Being my first winter burning this bad boy, I've definitely learned a lot. Thanks to this group for greatly shortening that learning curve.
 
Now that I'm exclusively ash, I can't get a decent 8 hour burn. I am going to have to find a way to source some oak or locust to burn with all the ash I have. Being my first winter burning this bad boy, I've definitely learned a lot. Thanks to this group for greatly shortening that learning curve.

So.. Ill be completely honest.. I dont know alot about the trees in your area.. in my house oak and black cherry are king other great species that I have burned in the stove that I really recommend are.. any species of hickory, any species of beech. but I really like copper beech.. dogwood, American holly, mullberry

Beech has similar BTUs as oak and seasons fast... Mulberry beats out some of the oaks in BTUs.. If you can get yourself some willow oak.. that is a gem in my area at roughly 30 million BTUs per cord.. that chit is heavy to so watch what size rounds you thinking about playing with..
 
So.. Ill be completely honest.. I dont know alot about the trees in your area.. in my house oak and black cherry are king other great species that I have burned in the stove that I really recommend are.. any species of hickory, any species of beech. but I really like copper beech.. dogwood, American holly, mullberry

Beech has similar BTUs as oak and seasons fast... Mulberry beats out some of the oaks in BTUs.. If you can get yourself some willow oak.. that is a gem in my area at roughly 30 million BTUs per cord.. that chit is heavy to so watch what size rounds you thinking about playing with..
The king of my immediate area is ash and maple then oak. Decent amount of red cedar. The challenge with oak is there isn't much on my land being that my land is lower and somewhat swampy. The neighboring property, we call the high woods for hunting purposes, is mostly oak. The owner of that property doesn't burn wood. Eventually I might ask if I can drop a tree every once and a while.
 
Now that I'm exclusively ash, I can't get a decent 8 hour burn. I am going to have to find a way to source some oak or locust to burn with all the ash I have. Being my first winter burning this bad boy, I've definitely learned a lot. Thanks to this group for greatly shortening that learning curve.
I am still learning to deal with the ash.... but a couple ideas for you.
  • In the past I have plugged some or all of the holes at the bottom of the refractory. There are 8 of them and a #10 machine screw fits in there perfectly.
    • I have not tried this recently, but in the past it helped to calm down the cat a bit.
  • Right now I have the secondary inlet partially blocked using my flat plate with a shim under it and a magnet on the outside to hold it in place. Shim is ~1/8" thick.
    • Seems to be keeping peak cat temps under 1650 with a 3/4 load of ash. Under 1550 with a full load of oak. Better but not as low as I would like to see. Burns seem to be clean according to my flue gas TC probe and I can easily go 8 hours on 3/4 loads. 1/2 loads leave me enough coals to relight but not much heat output at the end.
  • I tried adjusting my air control as I have not payed with that in a while did not seem to make much difference in peak cat temps, takes a bit longer to heat up and I am generally running higher air settings... which makes sense.
    • Originally it was just closed with the lever all the way back and the stove stone cold. (Factory setting)
    • I adjusted it by loosening the screw and pushing the cable in just a smidge, maybe 1/16 to 1/8"
  • You could also try blocking the EPA hole. I have done this in the past and found not much of difference in cat temps.
    • This is on my list of things to try when I get into some more ash.
  • I think you know this but sometimes running higher air settings keeps the cat lower in temp, but sometimes it drives it higher..... I think smaller loads with higher air settings might work... but I have not proven it out yet.
    • Of course the problem with small loads and high air is shorter burn times and a lot of heat.....
 
What kind of wood are you burning?
This stack is pretty much any and every hardwood mixed. It's a stack that was started many years ago with any downed wood or smaller trees that I cut. It's got red oak, white oak, locust, walnut, hickory, ironwood, cherry, ash and who knows what else. It's smaller splits no large splits.
Last night same wood full load and it was a very predictable burn and the cat reacted like I wanted it to and it was under 20* out. This morning good bed of coals after 11hrs, opened the air and let them burn down and warm the house. Cat was in the 600's over the coals so I loaded the box as it was in the teens and not going to get to 20 today. Cut the air back to 10% at 1050 and life was good. Again it steadily rose so I cut the air back at about 1350 but it decided it wanted to thrill me again. At 1430 the whooshing roar can be heard and it kept climbing to 1525 before it decided to settle. It did settle and is now cruising at 1120 but I could live without that thrill as it keeps climbing. Yesterday I smoke tested all around the stove thinking I might have an air leak but didn't find anything.
Weather says 50-60's next week so the stove will get a break and a cleaning. Need to replace my cracked glass and I'll inspect the cat and vacum it. I was getting a light rattle and it was coming from the secondary flap. I could see it with a mirror and it was closed and the stove wasn't very hot when I heard it. It stopped doing it but I'll pull the cover on it and inspect.
 
I'm certainly not laughing at your ordeal with ash burning, but I dealt with exactly these same issues last season when I burned ash. The stove was all over the place and completely unpredictable.
Now I only use it to augment my pine and oak loads. Ash works well for me in a 2:1 ratio burning off some black walnut which never seems to burn for squat.
 
I'm certainly not laughing at your ordeal with ash burning, but I dealt with exactly these same issues last season when I burned ash. The stove was all over the place and completely unpredictable.
Now I only use it to augment my pine and oak loads. Ash works well for me in a 2:1 ratio burning off some black walnut which never seems to burn for squat.
So what is it about ash that makes it burn so differently?
 
This is only my guess
I'm thinking that species seasons at different rates. Like the outer 2-3 inches will be dry. But the insides will be less dry.
Or it's the type of gasses it gives off when burning.
Ash leaves me a nasty mess in the bottom of the stove when I burn it by itself. It's clumps up and doesn't drop down into the pan for nothing. So maybe that's why the stove runs differently....
I really don't know, but I hate it.
 
So what is it about ash that makes it burn so differently?
Does anyone remember burning ash before the borer? I wonder if the fact that every ash of the last 5-10 years was standing dead from the borer has turned it from a trustworthy hardwood to a time bomb. I expect the mechanism is collapse and either rapid (somehow unnatural) offgas or reposition against engine inlet.
 
Does anyone remember burning ash before the borer? I wonder if the fact that every ash of the last 5-10 years was standing dead from the borer has turned it from a trustworthy hardwood to a time bomb. I expect the mechanism is collapse and either rapid (somehow unnatural) offgas or reposition against engine inlet.
If it is internally riddled with holes, that would do it.
 
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If it is internally riddled with holes, that would do it.
We need someone to drill up a couple pieces of oak and test that theory! In all seriousness though I was just reading that and thinking the same thing. More surface area/split will heat up n off gas quicker. That being said if anyone has any split ash they need to dump…I’ll go build some racks real quick ;)

No way can it be more violent than the pine I’ve been burning.
 
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.
 
Does anyone remember burning ash before the borer? I wonder if the fact that every ash of the last 5-10 years was standing dead from the borer has turned it from a trustworthy hardwood to a time bomb. I expect the mechanism is collapse and either rapid (somehow unnatural) offgas or reposition against engine inlet.
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.

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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?
 
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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 think I have found this to be true as well. I suspect the reason is draft, when you heat your flue up more you are getting more draft making the air flow more consistent.

I have seen my flue gas temps hang, usually around 500 (gas temp) and then they will start to climb again, I have been engaging my cat at 650 gas temp. Might be moisture.... not sure.

I usually get the back puffs when STT is < 350 but I do not always see it. It may be the real issue is flue temp and low STT is just a result of low burn rate. Something for me to look at next time I have the issue. Seems to occur more often in shoulder months which suggests it could be low draft as well.
 
I think I have found this to be true as well. I suspect the reason is draft, when you heat your flue up more you are getting more draft making the air flow more consistent.

I have seen my flue gas temps hang, usually around 500 (gas temp) and then they will start to climb again, I have been engaging my cat at 650 gas temp. Might be moisture.... not sure.

I usually get the back puffs when STT is < 350 but I do not always see it. It may be the real issue is flue temp and low STT is just a result of low burn rate. Something for me to look at next time I have the issue. Seems to occur more often in shoulder months which suggests it could be low draft as well.
I use my flue temp (internal) to determine when I engage my cat. Usually I engage the cat when flue temp is 650.
 
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..
 
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The secondary air inlets are still a mystery to me.
@Woodsplitter67 if your primary air was cut all the way to zero, Does the secondary thermocoupler still run and change? I guess it must be independant....
 
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..
I wonder if the primary air control cable could be hanging up. Obviously the thermostat on these stoves “works” but in you case say t stat was opening but cable had too much drag. It eventually reaches the point where t stat wins but by that time stove is too cool and flap flys open and you get that box of fire…
Just a thought.