Crack open the big screw on the face of the pump and see if there's any air in the pump head causing the noise.
After that I'd suggest playing with the dial and see if a lower speed setting helps the problem. Do you know what the previous pump it replaced was? It's possible that the new pump is a more powerful pump than that which it replaced.
Crack open the big screw on the face of the pump and see if there's any air in the pump head causing the noise.
After that I'd suggest playing with the dial and see if a lower speed setting helps the problem. Do you know what the previous pump it replaced was? It's possible that the new pump is a more powerful pump than that which it replaced.