Secondaries to Coaling transition

[neverstop]

How should secondary flames transition into the coaling stage? Usually ill get a lazy small section of secondaries and then a log end may catch on fire as those end. However, other times secondaries will abruptly end and the stove will backpuff (usually while I'm sleeping). I know it happened because I can smell it and catch the backpuff on my wyze cam.

Is this stage the most likely time for a backpuff to occur? Past couple of days have been rather windy, and a higher MC split may have made it into the load as I don't check every one.

Edit: just happened, no wind. STT 577 flue 12" from collar 333. Primary was closed 100%

 

[kennyp2339]

Primary was closed 100%

Thats the problem, close the primary then crack it open a little and see if that helps, theres a fuel rich issue going on inside the firebox, then it gets enough oxygen and lights off causing the backpuff

 

[neverstop]

Thats the problem, close the primary then crack it open a little and see if that helps, theres a fuel rich issue going on inside the firebox, then it gets enough oxygen and lights off causing the backpuff

I'll give that a shot on the next burn. However, when this happens the stove has usually been running for 1+ hr (depending on the size of the load) with secondary flames and the primary closed 100%.

Based on your response my assumption then is that flue/STT have dropped enough to cause a decrease in draft resulting in less air being pulled in through the secondary air inlet creating a fuel rich issue. As I said this occurs close to the transition to the coaling phase so temperatures are lower.