2023/24 VC Temperature discussion thread

[arnermd]

Burns from yesterday.... pretty good runs, I am pleased.

• Morning load was cold start, ~1/2 load of splits
• My midday burn had some wet wood, you can see I had to throw the cat in and out several times to get the burn hot enough..... classic wet wood burn.... Not recommended.
• Overnight burn was a 3/4 load of solid red oak, square splits packed pretty tight. Burned great.

General process was rake coals to back, load, air 100%, engage cat after 10-15 min, gradually reduce air to 50% after cat reached 1000.
My griddle temp is indicating ~50 - 60F low.... I need to fix that.

 

[Todd]

I was going to ask if the griddle temps were always that low? I take it with a down draft stove the hottest part of the stove would be in the back?

 

[arnermd]

Yeah my griddle reading is low, I confirmed with my magnetic gage and an IR gun. The back of my stove has massive fins cast into the back so I suspect it does not get that hot (surface temp) but a lot of heat comes off of it when the cat is engaged.

 

[AsylumResident]

Here is my burn from last night. Right now I'm doing cold starts when I get home from work.

Once I got the stove up to temp I engaged the cat with 100% air. When the cat hit 1000 I dialed it back to 50% air and didn't touch it for the rest of the burn. Three large ash splits, I wouldn't even consider the box 1/2 full.

Green is Cat and Blue is STT.

 

[arnermd]

Very nice.... you got a lot of cat time in there for such a small load. One of the things I track is time cat > 1000F. Looks like just about 3 hours for your burn. Very good...

 

[AsylumResident]

The program is very limited with their graphs. I am going to need to export the raw data and make my own graphs at some point. My plan is to do a few burns exactly the same to see how they differ. The cat stayed relatively high for awhile.

 

[arnermd]

Seems like good idea.....

Couple things I am noticing comparing your burn to mine....

• Your cat time is a lot longer than mine. ~2.5 hrs vs 3hrs but I had a 3/4 load and yours was 1/2
• My cruise temps were lower in general and yours seem more consistent.

Makes me wonder if I have more secondary air than you or maybe you just have a newer, more active cat. Could be about a hundred other things too.....

Very curious to see what your draft readings are at cruise....

 

[Woodsplitter67]

Burns from yesterday.... pretty good runs, I am pleased.

• Morning load was cold start, ~1/2 load of splits
• My midday burn had some wet wood, you can see I had to throw the cat in and out several times to get the burn hot enough..... classic wet wood burn.... Not recommended.
• Overnight burn was a 3/4 load of solid red oak, square splits packed pretty tight. Burned great.

General process was rake coals to back, load, air 100%, engage cat after 10-15 min, gradually reduce air to 50% after cat reached 1000.
My griddle temp is indicating ~50 - 60F low.... I need to fix that.


View attachment 318332

At 3 what happened.. did you do anything.. why is the plot crazy in and arount that time period.

 

[Woodsplitter67]

Here is my burn from last night. Right now I'm doing cold starts when I get home from work.
View attachment 318351
Once I got the stove up to temp I engaged the cat with 100% air. When the cat hit 1000 I dialed it back to 50% air and didn't touch it for the rest of the burn. Three large ash splits, I wouldn't even consider the box 1/2 full.

Green is Cat and Blue is STT.

This actually looks like a really good burn. Your cat at 1500 is a little high but not to concerning.. this may be how your setup likes to run.

If your going to try to replicate your burn.. Stick with the same specs of wood .. and weight what you put into the box..

You could get a baseline with one specs of wood and weight and then move to a different specs and see how your stove reacts.. Id be super interested in seeing you guys do something like this..

just a thought

 

[arnermd]

At 3 what happened.. did you do anything.. why is the plot crazy in and arount that time period.

That was me throwing the bypass in and out to get enough heat to burn the wet wood.... Operator error...

 

[Woodsplitter67]

That was me throwing the bypass in and out to get enough heat to burn the wet wood.... Operator error...

Thats interesting to see the stove react like that..

Whats up with the wood supply??

 

[AsylumResident]

This actually looks like a really good burn. Your cat at 1500 is a little high but not to concerning.. this may be how your setup likes to run.

If your going to try to replicate your burn.. Stick with the same specs of wood .. and weight what you put into the box..

You could get a baseline with one specs of wood and weight and then move to a different specs and see how your stove reacts.. Id be super interested in seeing you guys do something like this..

just a thought

This is basically the same set up and load size as the day before; three ash splits. Difference was we had 25-30 mph winds yesterday afternoon. I would say this load was more a 1/2 load where as the day before was a little less than a half load. Green = cat and blue = STT.

 

[AsylumResident]

I did my first hot reload in over a week. For the reload it was two large ash splits and two medium black locust splits. It didn't go as I thought it would. Air was dialed back to 50% when cat hit 1000 and wasn't touched after that.

 

[arnermd]

Thats interesting to see the stove react like that..

Whats up with the wood supply??

I think what makes it look odd is the fact that I am monitoring exhaust gas temp not the flue. With the stove cold there is a lot of temp loss in the exhaust gas with the cat engaged because the back of the stove is cold. When I bypass the cat the exhaust gas goes straight up the flue so temp sensor shows a dramatic rise and fall when I go in and out of bypass.

Wood supply: In these shoulder months I am pulling from my catchall pile, it is under tarp and on top of pallets, so not as dry as the good stuff in the shed. I was also burning from my end stack (not fully covered) and it had rained the night before, so wood was wet. In hindsight I should have let it sit in the house for a day or two....

 

[arnermd]

This is basically the same set up and load size as the day before; three ash splits. Difference was we had 25-30 mph winds yesterday afternoon. I would say this load was more a 1/2 load where as the day before was a little less than a half load. Green = cat and blue = STT.
View attachment 318425

They both look pretty good to me. Cat temps are good and 2.5 hours cat hot time.... seems good to me.

 

[AsylumResident]

They both look pretty good to me. Cat temps are good and 2.5 hours cat hot time.... seems good to me.

Now I need to get the magnehelic gauge set up and start collecting that data.

 

[arnermd]

This load was a real PITA.....

• Raked coals to back
• Loaded about 3/4 full, larger splits of red oak.
• After 5 mins enagaged the cat which came up to temp quickly and lit off nicely.
• At 1000F reduced air to 50%, at 1200 down to 40%, at 1400 dropped it to 25%
• Thought I had it under control but, then it rocketed up to 1550
• Air went to 0% and ultimately I had to close my key damper to kill the draft. I could hear the telltale whooosh of a very active secondary burn and even at 1500 I was seeing smoke out the chimney. Clearly I had a real smokey primary on my hands....
• Griddle temps were pretty low (even if you add 50 deg for my sensor error)

Maybe mositure content? Time to break out the good wood.

 

[Todd]

That’s interesting. You’d think with that high of cat temps your flue temps would be much higher, where’s all the heat going?

 

[arnermd]

Only place it can go, out the back of the stove. Has to be... right?

I want to thank all you vets out there for your service to our great country.... thank you.

 

[Woodsplitter67]

This load was a real PITA.....

• Raked coals to back
• Loaded about 3/4 full, larger splits of red oak.
• After 5 mins enagaged the cat which came up to temp quickly and lit off nicely.
• At 1000F reduced air to 50%, at 1200 down to 40%, at 1400 dropped it to 25%
• Thought I had it under control but, then it rocketed up to 1550
• Air went to 0% and ultimately I had to close my key damper to kill the draft. I could hear the telltale whooosh of a very active secondary burn and even at 1500 I was seeing smoke out the chimney. Clearly I had a real smokey primary on my hands....
• Griddle temps were pretty low (even if you add 50 deg for my sensor error)

Maybe mositure content? Time to break out the good wood.

View attachment 318455

Im not sure if we have talked about this. During a hot reload I see no advantage to raking the coals back. Doing so is only adds a substantial amount of heat right in front of the cat chamber.

During a hot reload the key is to keep things cool as possible so I dont rake back and I dont allow much of the wood to catch. The stove is already up to temperature and so if the catalyst was lit off.. it should pop righ off again.

I know there are slight differences in stove setup and each setup has its own little preferences.. If the stove was already up to temp.. Why rake back?

 

[arnermd]

Im not sure if we have talked about this. During a hot reload I see no advantage to raking the coals back. Doing so is only adds a substantial amount of heat right in front of the cat chamber.

During a hot reload the key is to keep things cool as possible so I dont rake back and I dont allow much of the wood to catch. The stove is already up to temperature and so if the catalyst was lit off.. it should pop righ off again.

I know there are slight differences in stove setup and each setup has its own little preferences.. If the stove was already up to temp.. Why rake back?

We have talked in the past, maybe last year and I agree, if nice bed of coals and hot, no need to rake back.
On this burn I did not have a lot of coals, cat was down to 350. So I raked them back.

I am also experimenting with this to see if I can make the primary burn slower by raking the small coal bed back. Theory is to force the smaller flame to spread slowly from back to front and get the cat up to temp quick.

With a full hot bed I have had limited success trying to keep the burn low.... I end up with a smoky mess, cat at 1550+ and low griddle temps. This is usually when I get the back puffing which forces me to open up the air....

Brought a load of the good wood up to the deck today, checked a couple fresh splits and MC was 14-16%. Wood feels light but solid. As we were stacking I could hear the red oak "ringing", that's how I know the red oak is good.... Got some ash mixed in there too.

 

[Woodsplitter67]

We have talked in the past, maybe last year and I agree, if nice bed of coals and hot, no need to rake back.
On this burn I did not have a lot of coals, cat was down to 350. So I raked them back.

I am also experimenting with this to see if I can make the primary burn slower by raking the small coal bed back. Theory is to force the smaller flame to spread slowly from back to front and get the cat up to temp quick.

With a full hot bed I have had limited success trying to keep the burn low.... I end up with a smoky mess, cat at 1550+ and low griddle temps. This is usually when I get the back puffing which forces me to open up the air....

Brought a load of the good wood up to the deck today, checked a couple fresh splits and MC was 14-16%. Wood feels light but solid. As we were stacking I could hear the red oak "ringing", that's how I know the red oak is good.... Got some ash mixed in there too.

ok.. I was thinking something different..when you were saying a hot reload I was thinking the catalyst like 800 (800 being an arbitrary number) from the previous load, and you were raking the coals back and dropping wood on top if that.... I could definitely see that load going nuclear.. and be a PITA

 

[JohnDaileyNH]

ok.. I was thinking something different..when you were saying a hot reload I was thinking the catalyst like 800 (800 being an arbitrary number) from the previous load, and you were raking the coals back and dropping wood on top if that.... I could definitely see that load going nuclear.. and be a PITA

What do you do when you have a low cat? Say 350. Just load it and let it slowly creep up to 1000 then cut the air?

 

[Woodsplitter67]

What do you do when you have a low cat? Say 350. Just load it and let it slowly creep up to 1000 then cut the air?

So I stay away from doing it like. I dont like doing it tats was cor a couple reasons the most important is.. alot of smoke is getting into the stovepipe.

If the catalyst is like 350 the stove is still pretty warm so it shouldn't take long to get it back up to temperature.. I normally will reestablish draft, SST and then re-engage the cat. I burn low alot so I try to burn clean when I can I don't like the Idea of creosote. I take the time.to get the stove back up to temperature and I do a mid-season cleaning. Burning really dry wood also helps.

Sometimes I do rake the.coals to the back to help things along. Once I get close to the draft I need, Ill move things around in the box, add wood and close the bypass to ensure it kicks off quickly.

 

[arnermd]

ok.. I was thinking something different..when you were saying a hot reload I was thinking the catalyst like 800 (800 being an arbitrary number) from the previous load, and you were raking the coals back and dropping wood on top if that.... I could definitely see that load going nuclear.. and be a PITA

I did not say I was doing a hot reload, you may have been thinking of the post by @AsylumResident. Hard to keep all the posts straight....

I avoid hot reloads, for the reason you stated.,... nuclear.