CP1000 replenishment pump not pumping sufficient volume

On my CP1000 the replenishment pump motor is running, the belts & gears are fine and don't appear to be slipping, the pumps are turning, the impellers are fine, the vertical pipes are not obstructed, I opened the adjusting screws all the way open.  The tanks are full.  When the replenishment is requested, I can hear the speed increase yet no fluid is pumped up the vertical pipes and out.  I have no replenishment, the system does not consume any chemistry.  All 3 pumps behave the same.  Can anyone tell me how fast the pumps/motor should be turning?  I measured the pump drive gear with a digital tach: 93 RPM normal rate and about 200 RPM in replenishment.  The manual says the speed should double which it does but I must assume I am not reaching the desired speed to move fluid.  The speed is about the same with the tanks removed - so not a bad pump problem.  Does anyone know what voltage should be seen at the motor?  Appreciate any thoughts.