I have this same stove and it runs like a champ. Its not too picky about pellets you use.
There is a combustion blower trim adjustment (on the control board) and there is a feed rate adjustment (by pressing "prime" and heat level button at the same time). Here is a link to the manual for your stove: http://timberwolffireplaces.com/products/pellet-burning-stoves/TPS35/
Sounds like your feed rate may be set too high. Also, check the burn pot gasket...it could be affecting air flow through the burn pot.