So my dad has a pretty new 602 that replaced his circa 1976 602. We were talking the other night about secondary combustion and he has not seen the secondary manifold burn at the top of firebox during the burn. I explained when the stove is reaching up to temp, close the primary air slide a bit until closed and the secondary air should take over. The Jotul manual has a schematic of the stove and I can see the secondary baffle and it looks like the air comes in from the back bottom of the rear plate. The air looks like it travels between the internal rear burn plate and the rear plate and up to the manifold. I looked on the rear plate of the stove and there is a piece of sheet metal that covers most of the rear plate and it provides an air gap. The sheet metal is understandably riveted in place to prevent blocking of the secondary intakes. The manual also states that the primary air should not be closed all the way. I would think that with the primary air control closed, there is still air getting by. From the Jotul manual- • You can now add three or four small-to-medium pieces of wood. Allow this wood to burn for several minutes. Once you are sure the wood is burning well, adjust the air control to your desired heat output level. Moving it to the right increases the heat; moving it to the left decreases the heat. Avoid operating the stove with the air control closed completely. • Does anyone have a diagram that shows the secondary intake and flue gas flows in the stove? I remember seeing one for the Jotul 118 on the Jotul site that was very good. I did a search of this site and a bit of the the net with no luck. When I go for a visit, the stove is usually cooling off for the day, so I have not seen it running. It does heat the area well though, and there was some learning curve. Thanks all.