I have a 3 HP dust collector with very poor suction but tornado like exhaust. I was wondering if the unit’s impeller could be turning in the wrong direction? Is there a way to check?

Turn the dust collector on and off. Then, look through the grill on the end of the motor. There is a disc with fins under the grill. That disc spins the same direction as the impeller. It must be spinning so it is throwing the material directly into the outlet. Almost like whirling and throwing a lasso.

Some blowers have clockwise rotation and some have counter-clockwise rotation.