Possibility of excessive flow rate
Check flowmeter.
Possibility of internal contact
Check vibration and noise. Perform overhaul.
Rotating, but water does not come out. Discharge quantity is not enogh to specified capacity.
Over load (Overcurrent) occurs.
Excessive water leakage from stuffing box
Electric motor does not work well with noise.
Water comes out at first, but it doesn't come out soon.