Looks like a nice stove. Didn't know they came out with that.
My Answer has a similar jacketed construction. I run the blower on the lowest setting constantly. With good, dry wood, it will not pull so much heat from the stove that it will inhibit proper combustion, but when my wood was not really dry my first season (even though I thought it was dry) I thought the blower was cooling the stove too much. I'm guessing that your wood isn't really as dry as you think it is. With dry wood, you'll be turning the blower up to cool the insert down during some times of the burn cycle. When I saw the picture in the brochure of the woman in the easy chair with her feet dangling in front of the stove, I can tell you that when the stove is burning correctly, her feet would probably be on fire.
When you tested the moisture content, did you split the wood and test it in the middle? What type of wood is it? Some woods (e.g. oak, hickory) test "low" with a standard moisture meter since their conductance is so different than other woods. Reading 20% on these woods with a moisture meter might really mean 24% - not quite dry enough to burn well, but dry enough to burn and make you think the stove is the problem.
I would suggest two things:
1) Get some kiln dried wood from a convenience store (the small bundles) for $5 or so and try burning that. If that burns really well, it's your wood.
2) Test your wood again with a multi-meter and read the resistance value in the middle of the inside of a fresh split. See
https://www.hearth.com/talk/threads/using-a-multimeter-to-measure-wood-moisture-level.40033/. This will give you a true reading, not "almost true" regardless of the wood species.
When you (likely) find out that your wood isn't as dry as you think it is, re-split this years wood into to smaller pieces (2-3" on a side) and stack it in a sunny, outside location that gets a lot of wind, and put a good cover over the top (but not the sides). Augment this wood during the season with some pallets or other scrounged, dry wood. Get more wood in the pipeline for next year.
As far as "where does the temperature sensor go", I would suggest that you contact the dealer for advice. Looking at the brochure, I don't see where it could go.
Good luck with it. Keep us posted on your progress. You'll get there. We've all been in this place our first season, and you sound like you may be farther along the learning curve than some of us were.