Hints about combustion chamber ? - Solo40

[rcollman]

I am ready for the next level. I realize I don't know if I am adjusting the secondary air flow to get things to a higher level. I am still happy with my wood consumption. Here is what I see and do. Any suggestions?

Typically with an established fire going, when I have the secondary air (lever pulled out almost all the way) set at it's minimum, I see a short flame, with some blue. This flame does not give the bricks any kind of red glow, and maybe extends into the combustion chamber 1 inch if that.

As I push the lever in, I start to see a longer flame. At some point it splits and curls up and fills the hemisphere. The curling flame is what I am looking for because I believe that means I have gasification. It fills the chamber with the dual curls and the bricks glow. The edge of the hemisphere is clearly defined. I am hard pressed to notice any blue flame.

The next level is when things are really cooking. The flame fills up the hemisphere, such that it is hard to observe the curl, or even the outline of the hemisphere. I think the flames spilling out of the hemisphere towards the peep hole. I consider this excessive and reduce the secondary air until I see a strong curl. I have only seen this last kind of flame recently, usually with a good supply of coals in the firebox and 8 inch deep of 3-4"" split ash pieces in the firebox.

When I first started using the Solo, I would refill the lite firebox no secondary air, then after 5 minutes give it full secondary air and forget about it for the rest of the burn. I think most of my wood is around 4 to 6 inches, I do have some 8 inch pieces which I have started to split after reading this forum.

The only creosote issue I can see at the moment, takes place in the firebox. The combustion chamber produces a fine powdered ash. I have not looked at my chimney, but did clean the tubes last week after 3 mil BTUs of wood.


Suggestions?

 

[garysec]

Want to see what you get for comments here because I'm not sure if I'm getting good gasification either but I do get a nice intense blaze and heating the home nicely. I've moved the secondary back and forth and just keep putting it in the middle because not sure what I'm looking for and seems to look good and most comments I've seen on here say put it in the middle. One question though on your tamper lever is your ball handle up, down, or straight out? Not sure if I'm suppose to push it up or down after sliding left and right or just leave it facing out. I think I remember reading in the book it said something about lifting it up and sliding be my don't seem to work like that.

 

[free75degrees]

Want to see what you get for comments here

me too, I have no idea what the best setting is and I'd like to know. Imagine if we are all using a sub-optimal setting and tweaking it a bit would save 10% of our wood.

One question though on your tamper lever is your ball handle up, down, or straight out? Not sure if I'm suppose to push it up or down after sliding left and right or just leave it facing out. I think I remember reading in the book it said something about lifting it up and sliding be my don't seem to work like that.

I have the same confusion. I goofed around with pushing/pulling it in and out an in every which direction and in the end i came to the conclusion that simply sliding it left and right is all that matters. Am I wrong? The manual definitely said something about pulling down or up while sliding it.

 

[55Razor]

Guys, I went through the same confusion with the secondary adjustment on my Solo 30. The manual does say to move the handle down, I think, slide the adjustment, and then move the handle back up to the straight-out attitude. I could never get what I would call a satisfactory result doing this, so I started to experiment. I found a way to kind of verify the secondary airflow other than the scale setting. Wait until the primary chamber is cooled down enough so that you can put your un-gloved hand into it, and put 4 fingers of 1 hand into the slot opening, turn on the draft fan, and you should be able to feel air blowing out from the holes in the slot. Now, you can slide the secondary adjustment back and forth, and you should feel a corresponding difference in the air flow. I found a couple of things out by doing this. One, moving the handle down to slide cut the flow off; I now only slide it back and forth, in the straight-out attitude, to adjust, and two, verify, with your hand, when you have a no-flow through the secondary nozzles. Then look to see where the handle is in relation to the scale stuck on the enclosure above the handle; I found that what I was shown by the scale to be 1/2 open was actually only about 1/4 or less open. I've reset the scale and my adjustment method, and now I have the control I should have over the secondary air. Also, your description of what you see as gasification is accurate; you're cooking! Hope this helps.

 

[rcollman]

Thanks 55razor,
My Solo40 does not have a scale but it does have a peep hole! I have noticed I can move my secondary slide handle up and down and it sort of does an all off or all on kind of thing. But I slide it to adjust the secondary air.

Maybe I will try to take a picture or two again. My first attempts sort of show what is going on through the peep hole but you have to have a good imagination to see the curl.

I guess my basic question is why would too much secondary air not be a good thing if gasifiction was happening?

Best Chris

 

[sweetheat]

set it in the center and forget it. you guy's are over analizing it. It is difficult not to get gasification. only time you would not get gasification is with the fan off. more air means a shorter burn less means longer burn. think of it like a choke. :lol: I do not know why it's even there. just confuses a lot of people! sweetheat

 

[free75degrees]

set it in the center and forget it. you guy's are over analizing it. It is difficult not to get gasification. only time you would not get gasification is with the fan off. more air means a shorter burn less means longer burn. think of it like a choke. :lol: I do not know why it's even there. just confuses a lot of people! sweetheat

Maybe, but what if there are points in the burn where there is a lot of wood surface area and a lot of gasses coming out of the wood and the setting is in the middle so there is not enough oxygen. Isn't it possible that there is some uncombusted wood gas going out of the chimney due to not enough oxygen? Or is it set up so that there is always plenty of oxygen? Where's nofo and his lambda sensor?

 

[sweetheat]

the Tarm manual speeks of a yellow blue flame through the viewing port. if your wood is more then 15% moisture content but less then 25% adjust a bit to the right or less secondary air, if using dry wood adjust knob a bit to the left or more secondary air. if the draft fan is on you are getting air to the fire. if your moisture content is more than 30% I'd wait and burn it next year! sweetheat

 

[rcollman]

more air means a shorter burn less means longer burn. think of it like a choke

A choke, it is dawning over marblehead. My initial focus was upon the firebox but the choke is about the oxygen/gas ratio in the gasification chamber and probably it's temperature. We want combustion to take place there. The lean setting is usually just fine (lots of secondary air). I guess there could be a worry if the gases fill the chamber and are igniting outside of the chamber on the way to the chimney. Too much kindling and/or entirely too dry wood. I would love to have those problems all the time

nofo and his lambda sensor

Yeah, just what I need (thanks google search). Should I connect them to a Mac, Linux or Windows dedicated computer? LOL The sun is up and I see I am definitely way over thunking things. But it is sort of fun getting down the basics from a different perspective. Thanks all.

 

[jebatty]

Just slide the air control left or right, forget about moving it up or down or in and out, unless Tarm has changed its operation from last year to new models this year. All the way to the right is most air to the firebox (primary) and least air to the gasification area (secondary air), and vice versa. Set it in the middle and forget it, for the most part. My only suggestion on varying this is if your wood is consistently more dry or less dry. If more dry, then it is possible that the lever should be a little bit futher to the left (more secondary air). If more wet, then the lever a little more to the right (more primary air).

That said, as the burn progresses you might achieve some gain in efficiency by adjusting during the burn cycle. But I neither have nor want to spend my days sitting in front of the boiler adjusting the air from time to time. Do all the experimenting you want, just to see the results, then find your good "middle" setting.