Lightning wrote: air in is being limited by air out
That's kind of half true. Under normal circumstances more gas volume goes out than comes in. Disconnect your stovepipe from the stove (please don't, really
) and the firebox will create its own draft, just like the can-style charcoal starter used for your barbeque. The stove will keep right on burning happily without a chimney as long as you keep the ashes clear. Chimney draft does two things: (1) provides adequate suction to remove products of combustion; and (2) if draft is more than "adequate", extra air is sucked into the stove to make the fire burn faster. Dampers of either type, MPD or baro, just reduce the influence of the chimney. It's OK if you reduce function (2) but it's deadly if you reduce function (1) too much.