I have an Ashley\US Stove Model 6041 pellet stove. First off I am assuming that this a new install and the stove is new or has been thoroughly cleaned. Last year I started off by being quite frustrated at times until I got things dialed in. It could be the pellets that you are using, you could also try and set the feed rate to less than 2.00 PPH. I have made some small modifications to my stove that has made a difference in the stove as well. I want to stress that I am not recommending that you do this without consulting an expert!! With the disclaimer done I will explain. IMHO the biggest difference that I made to the stove was to seal the two ash dumps, there is one on each side of the burn pot. What I believe occurred was that it forced more air up through the burn pot, making for a more complete burn. If you remove the burn pot you will see a metal cap in the rear. US Stove recommends to either remove it altogether or drill four or five small holes in it and then replace it. (I removed mine). I had started a thread last year you can check it out here,
https://www.hearth.com/talk/threads/sealing-the-air-leaks-in-us-stove-6041-pictures-included.101761/
An outside air kit is never a bad idea as well. All in all after a half of the winter of tweaking and tuning I find myself quite happy with the stove. My biggest disappointment is that no matter what I have tried I can't keep the glass clean.
Other than that it has kept my little cape over 70 all last winter while never having to go higher than number 3 except for short periods just to catch up. Maybe someday when I have a spare $4000.00 I'll get a beautiful Harman, but till then this "plain Jane" is keeping me quite comfortable.
If you need advice don't hesitate to yell, Gary