Here are some suggestions to check if you're having problems with poor draft....
1. Top of the chimney is too low, not extending above the top of a pitched roof or surrounding trees.
2. Dirt, creosote or soot lodged in corners or along flue walls.
3. Loose mortar or cracks in brickwork causing draft leaks.
4. Spaces between liner tiles.
5. Dislodged bricks of tiles wedged in the chimney.
6. Connecting stove pipe projects too far into the chimney.
7. Chimney clean-out door to loose.
8. Leaks around chimney connector pipe.