What is Secondary Burn?

[woodburn]

Okay, I know to many of you this must be a stupid question. I have seen many discussions on these forums about secondary burn, but I am not sure what it is or how to identify it. Here are my questions-

What is it?

How do you recognize that you have a secondary burn going in your stove?

I just got an Avalon Arbor. Is Secondary Burn the same idea for a downdraft stove like the Arbor as it is for other stoves?

 

[webbie]

https://www.hearth.com/econtent/ind..._and_new_Wood_stove_technology_for_a_newbie./

The simplest way to look at it - it is the gases from the wood burning, what we know of as "flame".

But by keeping it inside the stove and adding air at the right places, it can be enhanced and most of the heat exchanged from it.

Ideally, this should happen without much intervention by the user - given dry wood and a decent chimney.

Your stove does this in the rear, so it is harder to see at some points in the fire. Secondary burn in your stove occurs when the smoke is pulled down through the embers and then air is injected from the ceramic pieces in the rear.

 

[woodburn]

I think I've got this straight, but correct me if I'm wrong. The Arbor pulls the air down over the glass doors (airwash system?), then across the coal bed to the rear of the stove where air enters from the llittle holes in the ceramic. Does the secondary burn happen right there, or does it happen after that air that just crossed the coal bed is pulled into the ceramic piece to go up the chimney? I notice ash always seems to clog those little holes. Is that hurting the process?

 

[webbie]

The light ash should not affect things too much, although you will see (in the videos tradergordo posted) that he cleans his out!

The air that comes in above your glass is primary air and is also the air wash. That air burns the wood and releases the smoke (gases).....those gases then travel down through the ember bed where more air is injected (secondary air) through those little holes.

See the acclaim cutaway at:
https://www.hearth.com/econtent/index.php/wiki/Downdraft_Stove_Operation/

notice the tiny air channel which brings the air in through the rear of the ceramic. Yours is somewhat similar.