Well I tuned the thing up, and used it for a few weeks. It was much improved, but I'm still not in love with it. I did get an 8 hour burn ONCE. That required finding the perfect pieces of wood to fully utilize the box, and about 45-60 minutes of supervision after the reload. So that left me with 7 hours for sleep. That's OK, but it also requires that everything be timed perfectly, and I don't always know when I'm going to go to bed or wake up, so the added planning just complicates life.
The tune-up included fixing a bit of a design flaw with the air control. They have two squares holes sliding past each other, and the edges were catching. It felt like the "stop", but it was a false stop, and I could see I was never actually contacting the stop screw. A little sheet metal tweaking fixed that up.
The bypass also had a more defined stop after I cleaned up all the rust scale. I had better secondary burns after this too. I think I got a lot more heat out of the wood after the tune-up. But, in the end, we'll be saying goodbye to the Lopi. I just don't like an open-loop control system. It's too fiddly. I find it far too easy to not get the air "just right". My wife never could find the sweet spot, and she'd either cook us out of there or smoke it out. And with open-loop, changing wood species will alter the sweet spot. I can't expect her to compensate for that all the time--that's just not a reasonable request. The doesn't have 30+ years burning wood under her belt, and she doesn't have a mental BTU chart for all the wood species, or the wood identification experience either. There's just too many variables, and thermostatic control fixes all that.
I did find that burning an insert mostly on it's lowest sustainable setting was mostly adequate for our home during a week of below average daily temperatures. Here's some more furnace data from our test period.
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You can see we had a couple days with no fire, a couple days with fires starting late morning or early afternoon, one overnight when we didn't manage to save the fire, and a couple overnights when we did save the fire. I wish I had my reload times plotted on the graphs, but I wasn't that diligent.