secondary combustion questions

[woodzilla]

with this current cold snap. I am wondering if my stove is being used as efficiently as possible. Does air supply need to be closed completly for sec. Combustion to occur? When i do this when stovetop temp hits @400 I get a rolling flame for a min or so, then almost no flame at all. Chimney puts out more gray smoke. Should I be more concerned with stovetop temp, secondary combustion, or color of smoke from chimney(should it be clear).going to thank in advance

 

[jpl1nh]

You want to close your air supply much of the way but not all the way. You still need to have some air supply for combustion.

 

[marky_mark896]

Ok, I know this is a newb question, but how do I know if I'm getting second combustion? I assume the smallish, whispy blue/orange flames I see near the top of the box are 2nd combustion, is that right?

 

[begreen]

They can be almost ghostlike, drifting blue-yellow flames. Or with a hot full load of wood and plenty of air they can look like a blazing Niagra flowing at the top of the stove.

Here's a video of my stove in the Niagra mode:
http://www.youtube.com/watch?v=lR98Z4zvX8k

 

[marky_mark896]

Cool, thanks BeGreen. That's what I have been seeing.

 

[woodzilla]

thanks for input. Now, let's say fire is dying down no more sec flames, should air be increased?

 

[begreen]

That depends. In your case it "sounds" like you could give it some more air for awhile. How thick are the splits you're burning? Experiment a bit.

This really varies a lot from stove to stove and is affected by the flue, firebox size, wood, split thickness, etc.. In some stoves the show is over in an hour and there are several large black logs still glowing, giving off lots of heat and burning for several more hours. My stove has a smallish firebox, so the secondary show is usually over in a couple hours. If all that remains are large ashen coals, then they get raked towards the air (front on my stove) and air gets opened up to burn them down.