After about an hour of stove running, stove shuts down completely. Like it was unplugged. Causing smoke to come out of hopper. E1 is on control board meaning blockage . I've checked the flue both inside and out as well as the smaller intake air one. All good. I've called technician and he said take combustible motor apart for blockage which I did and it was clean. Do I need a new combustible motor? New vacuum sensor or what? Help meee