Smoke Indoors From New Castle Serenity Install

I installed a new Castle Serenity pellet stove in my house to replace my old wood stove that had draft problems and was less convenient than the pellet stove. The pellet stove works great, and from what I've read has a good flame, but we frequently get a bad smell of fumes in the house and have to turn it off and open a window. I'm wondering if my draft issues are coming back, but I thought the pellet stove wouldn't have that problem because it has a blower. I used 3" DuraVent pipe to connect my stove to the existing 8" wood stove chimney, and am getting fresh air from outside with a 2" flex pipe. Here are a couple photos of the install and chimney, does anything look off? I read the tips on if you have smoke in the house, but I didn't see anything that jumped out. I also saw something about calculating a vent resistance value, does my run have too many bends or is it too high or something?

I didn't use RTV or tape to seal the connections, I read that wasn't necessary for DuraVent pipe. Plus it's hard enough getting the pieces to connect, if I sealed it with RTV I doubt I would be able to disconnect them if I ever had to. I had the chimney recently cleaned by a sweep, and looking up inside I can see it's clear all the way to the cap.