When you first plug in the stove or turn up the thermostat, the exhaust blower will come on immediately and stay on for at least 15 minutes. This is a safety feature to make sure the exhaust smoke can successfully exit the house before the stove begins to feed pellets.
With a brand-new pellet stove or after annual maintenance, the feed tube is empty, so it will take time for the stove to re-prime the feed tube before pellets will begin dropping into the firepot. For most stoves, pressing the reset button once every two minutes (over the course of 15-20 minutes) will be enough to re-fill the feed tube. The Mt. Vernon AE may take a little longer. Dropping a handful of pellets directly into the firepot before starting it up can speed up this process.