Backward Thinking?

Recently we were asked why one of our multi-stage fans (9ms8) appeared to be under performing by up to 50%, and in this case, not holding printed stock securely on a screen printing machine.
Previous purchases had exceeded expectations, however this particular unit just didn't cut the mustard.
Our response was simple, "you're going backwards."
In this case, the customer had wired the motor so that the rotation was in the wrong direction.
Contrary to perception, our multi-stage motors will continue to pull air through the inlet and expel air through the discharge port even when the impeller is going the wrong way.
Performance will only be approximately 40% of the normal duty in flow and/or pressure.
Simply rectified, the customer was relieved and a lesson learned.
If you find yourself with a similar problem, maybe it's time to consider some backwards thinking.