I am getting ready to perform the final break-in burn on my new Jotul 3CB. It has something on the back which the parts diagram calls a secondary air inlet. It is a square area that slightly protrudes from the back. Is this where extra combustion air enters to meet EPA requirements to minimize smoldering? I noticed my logs still burned pretty good with all air inlets closed. In fact I was surprised at the continued combustion as I was trying to cool the stove off after having reached my 300 degree 2nd burn-in temp. Also, I noticed a few drips of something black had leaked onto my new slate hearth from this area. What's up with that??