Hoover U3721 Owner's Manual page 21

To check dirt tube
Disconnect cleaner from electrical outlet.
1. Remove paper bag. Remove
dirt tube by pushing to either
side to release clips. Lift dirt
tube up and out.
3. To replace dirt tube, position
it over lower seal and push
down. Insert one side against
retention clip. Push to snap
other side into position.
Replace paper bag.
2. Clean out dirt tube.