2023/24 VC Temperature discussion thread
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AsylumResident
Feeling the Heat
AsylumResident
Feeling the Heat
AsylumResident
Feeling the Heat
Interesting thing happened tonight. Loaded it up on a hot reload, no different than how I've been running the last month. I have been running hotter on the front end everything had been going good, temps relatively controllable, cat typically in lower 1300's for a peak, glass pretty clean, decent burn times but tonight didn't go that way.
About an hour and half in the cat hit 1400 I closed the air down. By two hours it hit 1550 and kept climbing. Once it ran over 1600 and my flue was about 1000 (didn't see that at first) I started working different variations with the primary air. After about 15 minutes of that the temps started consistently dropping. Not really sure what caused it. My glass was black, which was interesting because since I've been running hotter that hasn't been an issue. For some reason I had a smoking mess in the fire box this time. I know the wood is good, solid and dry.
About an hour and half in the cat hit 1400 I closed the air down. By two hours it hit 1550 and kept climbing. Once it ran over 1600 and my flue was about 1000 (didn't see that at first) I started working different variations with the primary air. After about 15 minutes of that the temps started consistently dropping. Not really sure what caused it. My glass was black, which was interesting because since I've been running hotter that hasn't been an issue. For some reason I had a smoking mess in the fire box this time. I know the wood is good, solid and dry.
Yep.... been there done that many times. My guess (and it is only a guess) is you had a smoky primary burn (coal bed not hot or thick enough?) and closing down the air made it worse (I have done this myself many times). In this kind of scenario I found closing my key damper down and killing the draft is the only reliable solution.
In the past I have also had some success opening the bypass damper, closing down the air all the way and just let it burn.... but with a flue already at 1000.... that's pretty hot.
AsylumResident
Feeling the Heat
The coal bed was definitely big enough and hot enough; I debated letting it burn down a little before I loaded it back up. I don't anticipate actually knowing why it happened this time, but it was interesting to watch unfold. The black glass really threw me off.
AsylumResident
Feeling the Heat
This is the graph from last night. Notice the STT, this is exactly why I wanted an internal flue probe to monitor that temp. The STT stayed just fine, the cat peaked at 1610, which isn't ideal but not a code red, but my flue was over 1100 when my cat peaked at 1610. That's very hot and there was a hot metal smell as well. Unfortunately my wifi monitor only monitors two temps. Maybe I'll switch and have my cat and flue on the wifi monitor. If I didn't have a probe in the flue I probably wouldn't have made the changes yet to try and lower the temps.
After the cat hit 1500 the first time I shut the primary air all the way down. You can see the cat drop but then climb back up. When it hit 1500 the second time I opened the air back up to about 50%, watched it, closed it some, opened it some and then left the lever at about 50% since the temps kept consistently dropping. It's amazing to me how hot that internal flue can get.
After the cat hit 1500 the first time I shut the primary air all the way down. You can see the cat drop but then climb back up. When it hit 1500 the second time I opened the air back up to about 50%, watched it, closed it some, opened it some and then left the lever at about 50% since the temps kept consistently dropping. It's amazing to me how hot that internal flue can get.
Interesting.... The blackened glass is certainly a good indicator that you had a smoky primary burn. Question is why..... (as you said sometimes this is just mental torture)
Maybe you choked the the air down too fast?
Would be interesting to know if you just let it go the first time you hit 1500 what would it have done.
Sometimes it is best to just blame these things on some unknown offense to the wood combustion Gods, offer an animal sacrifice and move on with our lives....
Here it is.... I think you have offended the Greek Goddess Hestia....
From Wikipedia: In ancient Greek religion and mythology, Hestia (/ˈhɛstiə, ˈhɛstʃə/; Greek: Ἑστία, meaning "hearth" or "fireside") is the virgin goddess of the hearth and the home. In myth, she is the firstborn child of the Titans Cronus and Rhea, and one of the Twelve Olympians.[1]
From Wikipedia: In ancient Greek religion and mythology, Hestia (/ˈhɛstiə, ˈhɛstʃə/; Greek: Ἑστία, meaning "hearth" or "fireside") is the virgin goddess of the hearth and the home. In myth, she is the firstborn child of the Titans Cronus and Rhea, and one of the Twelve Olympians.[1]
AsylumResident
Feeling the Heat
AsylumResident
Feeling the Heat
I just pulled the cat to see if yesterday's temps had any affect. I am now the owner of a cracked ceramic cat. A crack basically zigzags throughout half of the cat.
VC stoves should come with that statue as an ornament.
I better keep quiet my stove has been very tame. Even from cold starts or low relight run the STT up flip the damper wait for 1,000 and turn it down. from there it will slowly go into the 1300's settle and all is good. Hot reloads have been simple also, open the air and flip the damper load the stove, flip the damper and turn the air down at 1,000.
I'll bet I jinx myself and either go to 1600 or at the least have a nice back puff.
Well.... total train wreck last night. I do not know what you did to incite the wrath of Hestia but the curse has moved east..... This burn was one of the worst I have ever seen.
I followed my normal process, full load on a decent bed of coals I spread evenly. Only exception was I engaged the cat at 600 instead of 650, just to see if it would work. All seemed fine but it was not to be. I did notice that there was no flame visible through the glass, just an orange glow at the bottom.
At 21:40 I closed the key damper to kill draft, opened the griddle to take a peak and all the combustion was happening at the back of the stove, very smoky. Rather than leave the key damper closed I tried to save the burn by opening the damper, increasing air to move the fire to the front. When I saw flames in the front I closed the bypass and left air open, let it go for a bit and saw cat / flue temps peak then I closed down the air again and went back to bed. Flue gas hit 1350...... fortunately it came back down quickly.
At 23:20 we had round 2, at this hour I have no patience so I just messed with the draft, did not like what I saw so I closed the key damper, killed the air and went to bed.
For some reason this load decide to burn in the lower back corner, right at the secondary smoke inlet..... I am going to try raking coals to the front every time in the future to discourage this,
What a sh*tshow.... Looking for a small animal to sacrifice to regain favor of Hestia
I followed my normal process, full load on a decent bed of coals I spread evenly. Only exception was I engaged the cat at 600 instead of 650, just to see if it would work. All seemed fine but it was not to be. I did notice that there was no flame visible through the glass, just an orange glow at the bottom.
At 21:40 I closed the key damper to kill draft, opened the griddle to take a peak and all the combustion was happening at the back of the stove, very smoky. Rather than leave the key damper closed I tried to save the burn by opening the damper, increasing air to move the fire to the front. When I saw flames in the front I closed the bypass and left air open, let it go for a bit and saw cat / flue temps peak then I closed down the air again and went back to bed. Flue gas hit 1350...... fortunately it came back down quickly.
At 23:20 we had round 2, at this hour I have no patience so I just messed with the draft, did not like what I saw so I closed the key damper, killed the air and went to bed.
For some reason this load decide to burn in the lower back corner, right at the secondary smoke inlet..... I am going to try raking coals to the front every time in the future to discourage this,
What a sh*tshow.... Looking for a small animal to sacrifice to regain favor of Hestia
Wish me luck. Just filled the encore up for the first time ever. Only way to put more would have been put one under the plate or pack the ends with shavings! Sst350 cat at 1300 and climbing 
Edit. I suspect the stt is a false low due to the wood insulating the top from the flame.
Update 19:55
Stt at 450 cat at 1580-1610 and holding, secondary damper as open as it can currently be.
Primary air shut all the way off.
Update 20:25
Stt 500 cat at 1400 and falling. Primary air still at zero. Right side glass is clear left side hazed over. Flue at 275F (this is not an accurate reading), this is higher than were it normally runs by about 30F.
Edit. I suspect the stt is a false low due to the wood insulating the top from the flame.
Update 19:55
Stt at 450 cat at 1580-1610 and holding, secondary damper as open as it can currently be.
Primary air shut all the way off.
Update 20:25
Stt 500 cat at 1400 and falling. Primary air still at zero. Right side glass is clear left side hazed over. Flue at 275F (this is not an accurate reading), this is higher than were it normally runs by about 30F.
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I have been looking trying to figure out a way for you to get control over your secondary air flow…it sucks you have just one damper… the only thing that I can come up with is drill some bigger holes in the bottom of your refractory so the secondary air flow gets more bias vs the primary. I know that’s not doable on the fly and not a 5 min job. That being said the realization that my secondary air damper was meant to provide cooling air then tuning it to do so at a little lower temp has been a game changer.
I can confirm, a full load will give you lower STT for a while, for the reasons you stated. Totally normal and expected.
I agree with your line of thinking but, no way I am drilling holes in the refractory..... not even sure how I would do that. I would rather add a blower to stuff more air in there when cat temps are high. I have experimented with this for short periods of time and it works, but adds a lot of claptrap for a more permanent installation.
How did the burn end up overall? Inquiring minds want to know.....
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Still working like a charm for me. Last night did a very hot reload about 10PM to make sure I had a big enough load for overnight. Cat rose but was controllable peaked in the 1400's and settled nicely. Opened air just a little before bed and 8:30 this morning nice coal bed and 580's on cat. Opened air full and the cat rose to the high 600's waited a while and reloaded and closed the damper. I thought it might crash or stall but it rebounded nicely to 1,000 and I shut the air down to open about 10%. Cat ran up to the 1400's and settled and cruised slowly dropped back to 1,000.
I replaced my secondary thermostat last year and have not touched it since then. Could never get any info on operation theory but last year I watched it open when cat got to 1600. I'd say that's the theory behind it is to cool the cat if overfired. So far this year I've stayed away from the 1500 mark.
What temps does everyone have their Auber alarm set at? I set both lows and highs at 1700 as I really didn't want it going off. I can see this display so much better than my other meter that I was using. I can see this from across the room, the other I had to get up to check it.
I replaced my secondary thermostat last year and have not touched it since then. Could never get any info on operation theory but last year I watched it open when cat got to 1600. I'd say that's the theory behind it is to cool the cat if overfired. So far this year I've stayed away from the 1500 mark.
What temps does everyone have their Auber alarm set at? I set both lows and highs at 1700 as I really didn't want it going off. I can see this display so much better than my other meter that I was using. I can see this from across the room, the other I had to get up to check it.
AsylumResident
Feeling the Heat
Might just have been the wood. Some sapwood burns quickly.Chicken bones, exorcism, garlic and voodoo.... all ineffective.
@2230 cat was down to 800, stt was down to 375. Firebox was 1/3 full of “coals”, opened air up to 25% and went to bed. Subconscious wanted to check on stove cause I woke up at 330 to check on it. Stt and cat were 200F and hvac thermostat was still 2 degrees about setpoint. I’m calling it a win. Will attempt to replicate tonight with possibility of adding in pieces vertically at the ends and filling to the lid. Will see how well what all I have in the rack fits in.
Well the plan to stuff the stove got aborted. Got the pile about to where I had it last night and it caught…had to reload before the starter fire was burned down so there were a few chunks of coals in the way. Timing dictated it was reload now or not till tomorrow.
So we are gonna have a repeat from last night except this time the coals lit the new load front and center instead of back right corner.
So we are gonna have a repeat from last night except this time the coals lit the new load front and center instead of back right corner.
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