new shopvac has been used 3 times has no suction.

Just curious if its shell is closed and locked firmly, and in a proper position. You know, how you disconnect the top to empty out the bucket, then put it back on and secure with latches? If it's not seating in its proper place, it would suck air through the entire perimeter of the seal, and not the hose, hence no suction. This is just a hunch, obviously, not much else to go on.