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Post by martyn on Apr 24, 2023 23:03:23 GMT -8
You want to see how the white smoke reacts in the air, does it carry for a long time or disperse into nothing?
If it disappears then it is steam and not smoke.
The steam will come from damp refractory and or damp wood.
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jonasp
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Post by jonasp on Apr 25, 2023 0:21:39 GMT -8
You want to see how the white smoke reacts in the air, does it carry for a long time or disperse into nothing? If it disappears then it is steam and not smoke. The steam will come from damp refractory and or damp wood. that's a good point, it doesn't look like damp or it would be quite a bit of damp although the smoke doens't travel far either. I'll make a video of the smoke next time Thx! |
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Post by Vortex on Apr 25, 2023 1:36:21 GMT -8
ok let's see how it progresses. Today i started with a slower start up and lit the fire more at front top. Eventually it did overfuel again at 20% intake. i.imgur.com/bR6VOi9.jpgmaybe even less small wood at the top? Or should i start without the bypass so it'll go even slower? Once it overfuels and then slows back down into a nice vortex i still get the white smoke any reason for this? Light it on top below the port. That looks about right for the kindling but you have no middle sized pieces below, that can make it struggle and stall a bit after it has burned through the kindling, as it tries to transition straight from kindling to large logs. If it's overfueling then there is either not enough primary or not enough back pressure. Ah! you're using the bypass at startup - that's why it's overfueling, only use the bypass when the door is open and you are lighting it, then close the bypass and door at the same time. The 'white smoke' is probably steam. Steam will dissipate quickly as it drifts away from the chimney. In humid weather the air cannot support much moisture and so it becomes more visible, remember seasoned wood is still around 20% water even if your stove is completely dry. If you have easy safe access to your chimney when the stove is running, it should smell like a laundry vent and if you put your hand in the 'smoke', moisture will condense on your skin. Trev |
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jonasp
Junior Member
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Post by jonasp on Apr 25, 2023 3:04:38 GMT -8
ok let's see how it progresses. Today i started with a slower start up and lit the fire more at front top. Eventually it did overfuel again at 20% intake. i.imgur.com/bR6VOi9.jpgmaybe even less small wood at the top? Or should i start without the bypass so it'll go even slower? Once it overfuels and then slows back down into a nice vortex i still get the white smoke any reason for this? Light it on top below the port. That looks about right for the kindling but you have no middle sized pieces below, that can make it struggle and stall a bit after it has burned through the kindling, as it tries to transition straight from kindling to large logs. If it's overfueling then there is either not enough primary or not enough back pressure. Ah! you're using the bypass at startup - that's why it's overfueling, only use the bypass when the door is open and you are lighting it, then close the bypass and door at the same time. The 'white smoke' is probably steam. Steam will dissipate quickly as it drifts away from the chimney. In humid weather the air cannot support much moisture and so it becomes more visible, remember seasoned wood is still around 20% water even if your stove is completely dry. If you have easy safe access to your chimney when the stove is running, it should smell like a laundry vent and if you put your hand in the 'smoke', moisture will condense on your skin. Trev I'll test it next time without bypass! if there's not enough back pressure can I increase this by increasing the surface in the afterburner compared to the volume of the afterburner? I'll keep this thread updated and hopefully the system will stabilize after learning more about it or doing some small tweaks thanks again! |
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Post by Vortex on Apr 25, 2023 5:01:45 GMT -8
It's the top chamber surface area to volume ratio that you would adjust not the afterburner.
The bypass can make it overfuel because when you light the stove with it open there is no back pressure/resistance from the mass, so the fire burns faster, then when you close the bypass the gas flow rate drops suddenly which also drops the O2 to the fire suddenly, but the wood gas production carries on the same for a while until it adapts and so overfuels.
How's the oven temps looking?
Trev
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jonasp
Junior Member
Posts: 102
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Post by jonasp on Apr 25, 2023 9:41:38 GMT -8
It's the top chamber surface area to volume ratio that you would adjust not the afterburner. The bypass can make it overfuel because when you light the stove with it open there is no back pressure/resistance from the mass, so the fire burns faster, then when you close the bypass the gas flow rate drops suddenly which also drops the O2 to the fire suddenly, but the wood gas production carries on the same for a while until it adapts and so overfuels. How's the oven temps looking? Trev oh okey thanks for clarifying that, then it's most likely that which causes the overfuel! I should make the door of the oven this weekend, so far I've seen 230 degrees celsius on my thermometer which just lays in the middle of the oven floor. |
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jonasp
Junior Member
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Post by jonasp on Apr 25, 2023 22:26:09 GMT -8
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Post by Dan (Upstate NY, USA) on Apr 26, 2023 2:22:03 GMT -8
Hard to tell without a blue sky in the background to tell how quick the steam dissipates or doesn't
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Post by Vortex on Apr 26, 2023 2:28:37 GMT -8
Was that burn a full load or smaller amount? It's hard to tell if it's smoke against that grey cloudy sky, that is overfueling a little though and would explain smoke if it was at that stage. The flame should mostly stay in the afterburner, no more than just starting to lick around the front top edge of the afterburner shelf. You could try increasing the primary air a bit when it starts to overfuel, maybe just crack the door open a tiny bit and see how it behaves, otherwise yes increase the surface area to volume ratio of the top chamber.
Trev
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Post by masonryrocketstove on May 19, 2023 16:39:36 GMT -8
I wish I could weld things even half as nicely as you can, jonasp . That's a good looking build. How's it running lately? |
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jonasp
Junior Member
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Post by jonasp on Jun 8, 2023 23:24:04 GMT -8
I wish I could weld things even half as nicely as you can, jonasp . That's a good looking build. How's it running lately? Thanks a lot! i still consider my welds not that good and you don't see the amount of attempts i had to do on some hehe The last couple fires went well not perfect yet but it's been good weather here so no need to light the stove anymore. Next burning season i'll update on how it's going |
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jonasp
Junior Member
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Post by jonasp on Nov 27, 2023 0:56:37 GMT -8
The built is almost finished, need to add another small layer of limeplaster and some other small details.   The temps in the oven (the thermometer is in the oven door) it varies between 180-210 celcius and it also is a good indicator of how clean the burn was. I've had some stalls at the start but now i know how much kindlings i need to properly start the fire without stalling. I only use the bypass a tiny bit when it stalls or when the full system is cold. The stalls did create quite a bit of soot on the windows but also in the bell itself. I still have issues with overfueling but last couple of burns when the primary air is more than 20%CSA it might overfuel for a small amount of time or I get a full burn without any overfueling. drive.google.com/file/d/1JU90fKwvJptz9gZm_Lq6MMx89KHvTVuN/view?usp=drive_linkOverall it gives a great heating but still need to tweak so i can have consistent clean and efficient burns. |
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Post by Vortex on Nov 27, 2023 10:27:33 GMT -8
Looks great. I find when you get that where just the top of the firebox door glass gets smoked up, it's because the gas flow through the system is too slow and there's a backlog in the firebox creating a ceiling of smoke. It's usually because there's too much resistance somewhere or the mass is cold or still damp. I find mine lights best when the mass is 20c to 25c.
It's best to use just enough kindling so the startup is quite gradual, and light it with the door and bypass open, once you're sure the kindling has taken, then close the door and bypass together.
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jonasp
Junior Member
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Post by jonasp on Nov 30, 2023 0:12:40 GMT -8
Looks great. I find when you get that where just the top of the firebox door glass gets smoked up, it's because the gas flow through the system is too slow and there's a backlog in the firebox creating a ceiling of smoke. It's usually because there's too much resistance somewhere or the mass is cold or still damp. I find mine lights best when the mass is 20c to 25c. It's best to use just enough kindling so the startup is quite gradual, and light it with the door and bypass open, once you're sure the kindling has taken, then close the door and bypass together. The smoke on the door happens when the fire gets stale, I mostly don't get that anymore. My thinking was that the primary air sits pretty low and the fire more back so i get a stale air at the top front of the firebox when the system is running stale. The only issue I'm facing right now is that the system tends to overfuel at the peak for a period of time depending on the fire it might take 5-15min of overfueling before it get's stable again. Opening the door a bit helps to get it stable but it is annoying since I don't want to leave the door open and go out of sight of the fire.. I installed a grid at the primary air port and when i fully open that it's sometimes not enough to calm the overfueling, should i try increasing the primary air to prevent overfueling? or what other options do i have to make the full burn more stable? |
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Post by Vortex on Nov 30, 2023 5:33:55 GMT -8
Stale? Do you mean stall? Is the vortex forming properly? In your picture above the vortex looks sluggish. That palm tree shape indicates too much air. Without more information it's hard to say for sure but it sounds like too much resistance in the top chamber/mass, have you tried that?
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