Why isn't my Polaris working properly?
If the screen on the Polaris wall fitting is clogged, that will also cause of low flow to the cleaner. Disconnect the cleaner from the wall. Inside the wall fitting, there is a small mesh screen that needs to be cleaned periodically. Your problem can also be caused by the simple fact that the Polaris booster pump is not turned on or because your filter-pump is not turned on.
If you are still having problems, turn on the Polaris and watch the backup valve-- the bulbous fitting about 3 feet from the unit's head. Water should shoot out of this every 5 minutes or so. If it continuously flows from this fitting, then the backup valve needs to be replaced.
Finally try turning the head on its side. Are all 3 wheels spinning? If not, the belts could be broken or the unit could be clogged