2023/24 VC Temperature discussion thread

[Woodsplitter67]

Ohhh.... you actually open the bypass when the cat is hot and then load up? This is something I did not understand before.... I thought you let it burn down to coals and then loaded up....

When is the cat hot enough where you will open it and load up?

I am going to try that tonight....

@AsylumResident : you should never be bored with this stove..... Happy, sad, frustrated, angry, warm.... but never bored.

so yes.. I pretty much always use a small amount of wood to get the stove and catalyst up to temp.. never load alot of wood and start the catalyst really high.. load a smaller amount of wood and trying to get the cat to like 1k.. once the stove and cat are running and you feel good about it.. thats when I load the wood I wnat to burn for an extended time

 

[AsylumResident]

yes.. to all of the questions.. you got it

is this any different then how your doing things..

I do not use the smaller splits to get the cat up to temp. I let the smaller splits burn down to coals , put my full load on the coal bed, let that catch until the flue hits 650, close the bypass (regardless of cat temp), let load burn to being the cat up to temp, then adjust air as needed.

 

[arnermd]

so yes.. I pretty much always use a small amount of wood to get the stove and catalyst up to temp.. never load alot of wood and start the catalyst really high.. load a smaller amount of wood and trying to get the cat to like 1k.. once the stove and cat are running and you feel good about it.. thats when I load the wood I wnat to burn for an extended time

Interesting..... How have we been talking for a over a year and I did not realize this.... I feel like we need a dedicated thread where you can document your specific procedures.... Something we can edit and add detail to over time.

You say:

never load alot of wood and start the catalyst really high..

Isn't that what you are doing when you re-load with cat already hot? I am not understanding something.

I want to try this for tonight's burn, here is what I am thinking, please correct where I am in error.

• Right now: STT=350, Cat=390, flue gas= 263. Pretty thin bed of coals.
• Add 2-3 smaller splits on top of coals.
• 100% Air, bypass open, wait for STT=450-500.
• Close bypass, 100% air, bring cat temp to 1000 (I may not be able to get it there with such a small load)
• When cat peaks, open bypass, load full
• Close bypass immediately after reload (?? or should I wait a bit)
• Set air to 30-40%
• Go to bed....

 

[AsylumResident]

Interesting..... How have we been talking for a over a year and I did not realize this.... I feel like we need a dedicated thread where you can document your specific procedures.... Something we can edit and add detail to over time.

You say:

Isn't that what you are doing when you re-load with cat already hot? I am not understanding something.

I want to try this for tonight's burn, here is what I am thinking, please correct where I am in error.

• Right now: STT=350, Cat=390, flue gas= 263. Pretty thin bed of coals.
• Add 2-3 smaller splits on top of coals.
• 100% Air, bypass open, wait for STT=450-500.
• Close bypass, 100% air, bring cat temp to 1000 (I may not be able to get it there with such a small load)
• When cat peaks, open bypass, load full
• Close bypass immediately after reload (?? or should I wait a bit)
• Set air to 30-40%
• Go to bed....

I did just that a little bit ago. I couldn't get the cat up to temp. I would need ti add more wood.

 

[JohnDaileyNH]

Interesting..... How have we been talking for a over a year and I did not realize this.... I feel like we need a dedicated thread where you can document your specific procedures.... Something we can edit and add detail to over time.

You say:

Isn't that what you are doing when you re-load with cat already hot? I am not understanding something.

I want to try this for tonight's burn, here is what I am thinking, please correct where I am in error.

• Right now: STT=350, Cat=390, flue gas= 263. Pretty thin bed of coals.
• Add 2-3 smaller splits on top of coals.
• 100% Air, bypass open, wait for STT=450-500.
• Close bypass, 100% air, bring cat temp to 1000 (I may not be able to get it there with such a small load)
• When cat peaks, open bypass, load full
• Close bypass immediately after reload (?? or should I wait a bit)
• Set air to 30-40%
• Go to bed....

My mind is equally blown. Trying this tomorrow and seeing what happens

 

[AsylumResident]

As I sit watching this fire, I have the air at 0%. I am 2.5 hours into this burn, about a half load. I put the air at 0% an hour ago when the STT was about 510. Over this hour the STT has climbed to 600. I really need this explained to me. Doesn't make any sense to me at all.

 

[Woodsplitter67]

Interesting..... How have we been talking for a over a year and I did not realize this.... I feel like we need a dedicated thread where you can document your specific procedures.... Something we can edit and add detail to over time.

You say:

Isn't that what you are doing when you re-load with cat already hot? I am not understanding something.

I want to try this for tonight's burn, here is what I am thinking, please correct where I am in error.

• Right now: STT=350, Cat=390, flue gas= 263. Pretty thin bed of coals.
• Add 2-3 smaller splits on top of coals.
• 100% Air, bypass open, wait for STT=450-500.
• Close bypass, 100% air, bring cat temp to 1000 (I may not be able to get it there with such a small load)
• When cat peaks, open bypass, load full
• Close bypass immediately after reload (?? or should I wait a bit)
• Set air to 30-40%
• Go to bed....

Sorry.. I didnt get this until this morning

Im doing another burn this morning.. Ill post in a new thread

 

[arnermd]

Interesting..... How have we been talking for a over a year and I did not realize this.... I feel like we need a dedicated thread where you can document your specific procedures.... Something we can edit and add detail to over time.

You say:

Isn't that what you are doing when you re-load with cat already hot? I am not understanding something.

I want to try this for tonight's burn, here is what I am thinking, please correct where I am in error.

• Right now: STT=350, Cat=390, flue gas= 263. Pretty thin bed of coals.
• Add 2-3 smaller splits on top of coals.
• 100% Air, bypass open, wait for STT=450-500.
• Close bypass, 100% air, bring cat temp to 1000 (I may not be able to get it there with such a small load)
• When cat peaks, open bypass, load full
• Close bypass immediately after reload (?? or should I wait a bit)
• Set air to 30-40%
• Go to bed....

Last nights burn....
- Followed procedure above
- Seemed to do fine, I did have some auroras a couple hours in but not bad enough to back puff.
- Woke to a lot of unburned wood in the firebox, glass was black but not real bad.
- Opened air to 60% and got a few more hours out of the burn.

Seems to work although cat temps are higher than I would like to see for long periods of time.

Might try again with increased air, might bring down cat temps and end with a more complete burn?

 

[arnermd]

As I sit watching this fire, I have the air at 0%. I am 2.5 hours into this burn, about a half load. I put the air at 0% an hour ago when the STT was about 510. Over this hour the STT has climbed to 600. I really need this explained to me. Doesn't make any sense to me at all.

Yeah sounds familiar.... the lever on the right is merely a suggestion regarding level of heat....

My guess is you had a smoky fire going and it was just making lots of fuel for the cat. Was cat temp pretty high?
Things like this are why I think some of the secondary air is supporting primary combustion, but hard to say for sure.

I am starting to think our stoves really do not like low air settings, unlike @Woodsplitter67 setup.

 

[sargeott]

so yes.. I pretty much always use a small amount of wood to get the stove and catalyst up to temp.. never load alot of wood and start the catalyst really high.. load a smaller amount of wood and trying to get the cat to like 1k.. once the stove and cat are running and you feel good about it.. thats when I load the wood I wnat to burn for an extended time

Your technique is almost exactly what I have to do for a good reliable burn. If I vear away from those habits, I start to have problems.
Example:
Loaded up the stove for my usual overnight burn at 10pm. Set alarm for 330am to check and top off stove (my normal routine).
At 330am this morning the fire box is empty and very little coals left bizarre and not typical. I now get lazy and want to go back to sleep.
Stove is still hot so I repacked it, ran it in bypass for 10 minutes, kicked the cat back in and choked the air to 40%.
Wake up at 6am and the house is cold and the stove is barely running with a full box of fuel.

I clearly didn't wait long enough for the stove to get the cat operating range right.

 

[sargeott]

As I sit watching this fire, I have the air at 0%. I am 2.5 hours into this burn, about a half load. I put the air at 0% an hour ago when the STT was about 510. Over this hour the STT has climbed to 600. I really need this explained to me. Doesn't make any sense to me at all.

My stove doesn't do that. If I put it at 0 the stove craps out and all temps drop.

 

[AsylumResident]

My stove doesn't do that. If I put it at 0 the stove craps out and all temps drop.

This is where @arnermd theory of secondary air infiltrating into the primary combustion comes into play with our bigger Defiants. To me it seems a little bit dangerous. If there is no way to really ‘choke’ down the fire in a run away situation, because we have no control of the secondary air, how could we be liable for an over fire situation? Honestly, if I wasn’t in this forum, I defiantly would have over fired this stove countless times by now. I’m sure my cat would be destoryed.

 

[AsylumResident]

Yeah sounds familiar.... the lever on the right is merely a suggestion regarding level of heat....

My guess is you had a smoky fire going and it was just making lots of fuel for the cat. Was cat temp pretty high?
Things like this are why I think some of the secondary air is supporting primary combustion, but hard to say for sure.

I am starting to think our stoves really do not like low air settings, unlike @Woodsplitter67 setup.

This is the graph from this shorter burn. The cat didn't get to high. I need to find a way to get more temperature increments on the graph. It doesn't look like it on the graph but the STT hit 600 when it peaked. At 6:30 I put the air to 0% and you can see the STT just steadily increase. Nothing bad or worrisome, other than the fact that I cut the air all the way down and my primary combustion increases.

 

[AsylumResident]

This is the graph from this shorter burn. The cat didn't get to high. I need to find a way to get more temperature increments on the graph. It doesn't look like it on the graph but the STT hit 600 when it peaked. At 6:30 I put the air to 0% and you can see the STT just steadily increase. Nothing bad or worrisome, other than the fact that I cut the air all the way down and my primary combustion increases.

View attachment 319532

Also, so far I have not been too successful with burns with the air lower than 40%. Typically 50% is about as low as my stove likes to operate decently.

 

[Woodsplitter67]

Yeah sounds familiar.... the lever on the right is merely a suggestion regarding level of heat....

My guess is you had a smoky fire going and it was just making lots of fuel for the cat. Was cat temp pretty high?
Things like this are why I think some of the secondary air is supporting primary combustion, but hard to say for sure.

I am starting to think our stoves really do not like low air settings, unlike @Woodsplitter67 setup.

So just a question.. whatS wrong with 600 degree STT

 

[Woodsplitter67]

As I sit watching this fire, I have the air at 0%. I am 2.5 hours into this burn, about a half load. I put the air at 0% an hour ago when the STT was about 510. Over this hour the STT has climbed to 600. I really need this explained to me. Doesn't make any sense to me at all.

Why do you worry abor a 600 degree STT..

 

[AsylumResident]

Why do you worry abor a 600 degree STT..

I'm not worried about 600 STT. I'm worried that I put my air to 0 and my STT continues to increase, by almost 100 degrees. Is it an ill placed expectation that the temperature of the stove should be somewhat controlled by the air control?

 

[Woodsplitter67]

I'm not worried about 600 STT. I'm worried that I put my air to 0 and my STT continues to increase, by almost 100 degrees. Is it an ill placed expectation that the temperature of the stove should be somewhat controlled by the air control?

so when your temperature is spiking.. whats going on in the box

 

[AsylumResident]

so when your temperature is spiking.. whats going on in the box

How much detail are you looking for? There are active flames in the box and the cat temps are usually on the decline. The off gassing and smoking is done but the coals are obviously built up and burning down. Air is at the lowest but there is still quite a bit of active flame.

 

[Woodsplitter67]

How much detail are you looking for? There are active flames in the box and the cat temps are usually on the decline. The off gassing and smoking is done but the coals are obviously built up and burning down. Air is at the lowest but there is still quite a bit of active flame.

so this active flame is normally a seconday burn inside the box.. it can be well above the splits .. like the upper part of the box.. or it can be near the actual splits themselves.. yesterday I had secondary burns right in front of the glass .. here is a picture of a burn.. the this is not a active flame on the split this is a ghosting flame.. is this what you have

in the second picter is a secondary burn more over the split.. see how very lazy it it..

Is this similar to what your experiencing

 

[arnermd]

How much detail are you looking for? There are active flames in the box and the cat temps are usually on the decline. The off gassing and smoking is done but the coals are obviously built up and burning down. Air is at the lowest but there is still quite a bit of active flame.

Do you know about the EPA hole? (Not sure why we call it that) If not.... there is a hole in the bottom of the stove, just in front of the flapper. I am guessing it is 3/8 - 1/2" dia. It allows primary air to bypass the flapper, so even if the flapper is closed there is still some primary air coming in. I have experimented with plugging it with no real conclusions... nothing is consistent.

Wish I had a better explanation for you but I don't.... Best I can offer is, your experience is very much in agreement with mine.

If you look at my burn from last night the STT is all over the place, as high as 550 with 30% air and it never seems to stabilize even though the air setting was constant. Obviously something else effects STT not just the primary air setting.....

 

[AsylumResident]

so this active flame is normally a seconday burn inside the box.. it can be well above the splits .. like the upper part of the box.. or it can be near the actual splits themselves.. yesterday I had secondary burns right in front of the glass .. here is a picture of a burn.. the this is not a active flame on the split this is a ghosting flame.. is this what you have

in the second picter is a secondary burn more over the split.. see how very lazy it it..

Is this similar to what your experiencing

View attachment 319545 View attachment 319546

I would say it was just like your bottom picture. It was directly off the top of the splits.

 

[AsylumResident]

Do you know about the EPA hole? (Not sure why we call it that) If not.... there is a hole in the bottom of the stove, just in front of the flapper. I am guessing it is 3/8 - 1/2" dia. It allows primary air to bypass the flapper, so even if the flapper is closed there is still some primary air coming in. I have experimented with plugging it with no real conclusions... nothing is consistent.

Wish I had a better explanation for you but I don't.... Best I can offer is, your experience is very much in agreement with mine.

If you look at my burn from last night the STT is all over the place, as high as 550 with 30% air and it never seems to stabilize even though the air setting was constant. Obviously something else effects STT not just the primary air setting.....

I am aware of it because of your posts from last year and the schematic you drew up. I am always aware you did play with variable with no real result. Due to your experience, I didn't plan to mess with it much.

 

[Woodsplitter67]

I would say it was just like your bottom picture. It was directly off the top of the splits.

So you dont have active flames in your box.. You have secondary burns. The stove is designed to do this and nothing to worry about. normally this happens.. for me anyway.. near the end of the offgassing.. prior to coaling.. the other indication is that your cat temperature is dropping because the fuel is being burned in the box.. dont change anything when this happens.. let it finish the cycle.

Your STT will spike.. its ok it won't go to 700 and its not prolonged and your not going to warp anything

as described above the epa holes are letting in the air.. air still needs to be introduced into the box to allow any kind of burn

 

[AsylumResident]

So you dont have active flames in your box.. You have secondary burns. The stove is designed to do this and nothing to worry about. normally this happens.. for me anyway.. near the end of the offgassing.. prior to coaling.. the other indication is that your cat temperature is dropping because the fuel is being burned in the box.. dont change anything when this happens.. let it finish the cycle.

Your STT will spike.. its ok it won't go to 700 and its not prolonged and your not going to warp anything

as described above the epa holes are letting in the air.. air still needs to be introduced into the box to allow any kind of burn

I asked to have it explained and my prayer was answer. I appreciate it. In my mind I was lumping that experience into the experience of the run away the other night. But I do understand the concept and I do, now, understand the difference in the active flame vs the secondary burn flame (auroras).