How to properly operate my Drolet Tundra?

I had my first fire in my Tundra on Nov 1, been burning 8-9 days now. Weather has been in the 40s during the day, 30s at night. 2200 sq ft old farmhouse. It does a great job of heating things up quickly, in part because it's not cold out yet. So I find I only fill the firebox 1/3 to 1/2 full. That heats the house up for the next 8-12 hours.

My uncertainty is that I'm having trouble keeping the secondaries going. There's a chance my wood isn't dry enough (Mrs. Claus asked me to wait until Christmas for a moisture meter so Santa would have something to get me). But I also wonder if there is a minimum amount of wood the firebox requires to have critical mass for enough heat to keep the secondaries going? I also wonder if I'm burning the small loads so far to get the house up to temp, after which there is less smoke for the secondaries to burn? In other words, do the secondaries burn only when there is smoke coming off the wood, or also even once most of the wood is glowing red coals?

For example, the house was 64F at 4:30 pm after work. I filled the firebox 1/3 full with pretty small stuff. Cold start. After an hour the house was 67F, I turned the tstat down in order to close the damper. About 5 minutes later, I had some blue wispy flames coming up from a couple splits, and rolling but weak secondaries, sometimes they would go out and then reignite. I don't know if they were weak because not enough wood, wood too wet, or the wood was nearly out of smoke to burn. But then I went outside and could smell a little smoke.

What am I supposed to see typically? What does the wood look like when the damper is closed and the furnace is idling?

Just trying to learn from other's experiences so I don't spend forever trying to figure it out.

Or, said another way: If I load the firebox half full and burn with air inlet open for 45 minutes to heat the house, then if the air inlet remains closed indefinitely after that, how long should I expect to see the secondaries keep burning?

I did just that this evening, and the secondaries stayed lit for about 20 minutes with the damper closed until they died off. No flames from the splits either. Opened the air inlet for 5 minutes to relight/reheat everything. Had humble/modest yellow flames, a bunch of coals though. Closed the air damper and secondaries died within about 3 minutes.

That's a load of mostly box elder and basswood. I'm a wood beggar not chooser.

Curious if this is normal?

Thanks all for your replies.

Regarding wet wood...in the last 24 hours I've burned a bunch of smaller stuff including some 2" rounds of basswood and hard maple, both unsplit. Some of the darn things were sizzling and had some foam coming out the end for a couple minutes. 12-18 months drying, uncovered. I haven't had that with any of the bigger splits (3-5 inches) that were drying for 6-18 months in the same stacks. But I suppose they probably aren't super dry either.

Sloeffle, my secondaries look like that, just not for long, or without more wood. I'm encouraged that you can do it with just one log and some coals. In the last 9 months I've busted my hump from 3 cords (that I'm burning now) to 6 cords (mostly) dry for this winter plus 14 cords of c/s/s inventory. So I'm almost 3 years ahead and I'm looking forward to easier burning down the road. I also plan to top cover.

Most of my wood is from treelines, which is mostly box elder for now, so I'm going to have to figure out how to burn it. For the 16/17 and 17/18 stacks, I've been leaving box elder splits 5-8 inches, hoping I can get longer burns with the size, and that they'll dry fine enough after 3 years. I do have about 3 cords of locust/ash/crab apple/elm, so I'm looking forward to trying that in a couple years.

Maybe with cooler weather this week I can get a better feel for how my wood will work when the firebox stays hotter longer to keep the house warm. I'll keep an eye out for some of the eco bricks.

Thanks again.

I like it. I'd buy it again. Good value for the dollar. I don't have much comparison, it's my first furnace, my only other experience is several years tending the wood stove in my parent's house.

I like the glass door, well at least that I can see the burn status without opening the door. I don't use the ash pan, I just shovel them out with the shovel SBI included with the furnace. Workmanship seems pretty good, although some design aspects are so simple they aren't optimal (for example, the blower isn't sealed well to the housing so there is some lost air flow there.) I am quite impressed when I see the secondaries kick in. When the motor opens/closes the air damper, the damper door has developed a clang and it doesn't seem to be very smooth, but that might be just mine.

Regarding operating performance, I'm still trying to figure that out. I frequently catch a whiff of smoke outside, which I hadn't expected. I suspect it's my wood. Despite my previous posts, some times that I've burned really dry and smaller stuff, then I thin my problem is excess offgassing going up the chimney that the secondaries didn't provide enough air to burn. Other times, for example if I have a split that's bigger than the rest, it seems to have trouble keeping the secondaries going by itself after the smaller pieces have turned to coals.

I just cleaned the heat exchanger tubes for the first time last weekend. They had more creosote than I would have expected, but again, I'm still trying to learn the furnace, with the handicap of low-density wood that appears to have a variety of moisture contents from quite dry to more damp than desired. Plus, the wife does her best during the day with my instructions, but I'm not around for first-hand observation or operation.

A couple weeks after I took delivery, I hadn't even registered or installed the furnace yet but SBI found and called me to say the high limit temp switch might be faulty. I did an electrical check, sure enough it didn't work, so they sent me a replacement, and it was easy to install. Later, I noticed a firebrick had a void in it that crumbled apart, I sent them an email with pictures and they shipped me another no questions. Even before my purchase I had a series of technical questions and they always emailed back within a day. Overall I'm quite pleased with SBI's service.

Does that help? Let me know if you have more questions. Good luck!