its called a refractory burn plate. if you have your manual it has a list of parts with pictures so you can locate where it is. If not its just the stone? non metal back plate of the firebox. those holes when stuffed with ash, I believe, slow the sir to the secondary burn chamber and would slow the burn of my stove, it didnt really have much of an effect on the glass. Do you have control of the temperature of the air handler with the damper closed? I believe the root of my problem is with the damper gasket. when closed air is getting in and renders the secondary air handler moot. this results in a hot fire and clean glass. I don't feel comfortable loading it up at night though if I cannot control the rate of burn. I think the dirty glass in general is as you say, poor airflow and design.I'm late to the party here but I have a Intrepid flexburn with about 2 years experience running it. I have the same issues with the glass getting dirty quickly. jstol I see your post where you vacuumed two small holes in the burn plate that took care of this issue. What burn plate are you referring too? When I bought the Intrepid was told by dealer right off not to expect the glass to stay clean. Maybe this is my problem as well??? The Damper gasket is a bear to replace correctly. The track needs to be perfectly clean and the damper closed on it to hold it in place till the gasket cement can dry. Otherwise the damper would need to be removed to facilitate cleaning and gasket replacement. Fun stuff. I attribute the dirty glass issue to the design of the airflow within the stove.