Lightning wrote: Is the combustion air automatic? Does it open as the stove temperature falls? If not, I believe this is a bulk of the problem and a baro should be a huge improvement.
The Surdiac stove has a round intake port (approx. 3") on the lower back of the stove, which is covered and regulated by a mechanical "flap", (much like the one used on the bottom of your toilet tank). This flap is connected to a gearbox, that is controlled by 2 outside sources. 1 is the knob that you set to a desired temp, (referenced 1-9, but "never" needs a setting above 3), and 2, a heat probe that is affixed across the heat exchanger, externally, which feels the temp of the stove, and tries to regulate it to the setting you've adjusted it to. As the stove temp drops, the valve opens to allow more air. When I awake in the mornings to an "almost" dead fire, (After a week or so of burning), this intake flap is always wide open.
This is what's confusing me. Is the fire dying because the lower portion of the grates are now clogged, and it's starving for fresh air thru the coal bed, or is it ash accumulating around the "mostly" closed MPD, and restricting the exhaust flow?
Here's a couple pix of the intake system.
In the lower pic, you can see the adjustment knob (lower left of pic), and the cable attaching it to the gearbox. The wire going to the back of the heat-exchanger (above the stove pipe connection) is the temp sensor. Notice the open MPD, (only used in this position for starting...stove is off in this pic), and the lack of space for a Baro. I think if I get creative, I can "mickey" one in there, but won't be able to utilize a conventional "tee".