maintaining smoke free slow burn after several hours of clean burn

[mar13]

I'm on my second winter with my T5. This year I'm burning up a lot of seasoned alder (<=15%mc). I got the wood before my first winter with this stove so I created fairly large splits as I was wary of posts regarding the T5 tending to run hot. (I can make them smaller, but not larger!) Anyhow, with outside temperatures in the 40s, I've been getting a very clean burn with the flue prob thermometer running around 700 degrees. I'll shut the fire 80% down and it'll run clean for few hours - if I didn't cut it down that much I might breach 900 degrees during start up. After 4 or so hours, though, the fire will settle down to mostly coals but there will still be some good size chunks that are a mix of char & coals on the same chunk, with with very little or no visible flame. The chimney then will be showing a small-medium amount of smoke. The flue thermometer might be down to 450. Increase the air to 50% and the smoke goes away and I might get a few lazy small flames or increase the ones already existing..

So what should I be doing to consistently get a clean burn all the way through without needing to increase the air a few hours in? Perhaps I need more smaller splits mixed in or my splits are too big (4 splits fill the stove)? I have a 20+ straight up chimney (mostly inside), so I suspect good draft apart from mild temperatures. I guess I could try a load with more medium and small splits, but I was under the impression that big splits were better for longer burns.

 

[ABMax24]

Those are big splits, split a couple in half, try 6 splits and 8 to a stove load, you'll likely see better results, there's also nothing wrong with shutting the damper completely to keep temps under control when doing this.

 

[Grizzerbear]

Yea I have had this problem before and it's always when I have say a half load of wood or like you stated 4 bigger splits. That's why I like a mix of sizes. Like abmax24 said try some smaller split sizes and mix them up. Put your big splits on bottom and some smaller on top. The smaller splits will coal up faster and fall down around your bigger splits and help burn them up.

 

[mar13]

I'm using some smaller splits today with good results. I think I just couldn't get enough wood in my 2 cubic foot box with the large splits. Eventually they would not keep each other hot after they burned down to smaller size chunks making too much space between them. So I guess big splits are okay as long as they have small splits to stick in between them, a bit like that parable of fitting rocks and pebbles into a cup. There's still a lot of winter ahead of me to experiment.

 

[thunderhead]

I am also new to the T5 and have this same issue. I feel like there's a narrow line between splits too small and a nuclear startup and splits too big and a slightly smoky late-burn. Maybe 2 big splits with 3 medium on top is the right mix?

I'll get it one of these days. Have had a couple perfect overnight burns, thanks to begreen's help, but am still working on repeating that consistently.

 

[SpaceBus]

You will figure out what load you need for the temperature/weather in time. I can look at the outside and inside temp plus the forecast to determine how much wood to burn in the morning or at night.