DAB NKV 1 Instructions De Mise En Service Et D'entretien page 23

The motor protection trips too frequently.
The pump does not deliver.
The pump does not prime.
The pump supplies insufficient flow.
The pump flow rate is not constant.
The pump turns in the opposite direction
when switching off.
The pump vibrates and operates noisily.
ENGLISH
− Look for possible faulty insulation of the
motor, checking the phase resistance and
insulation to earth.
− Ensure that the environment temperature
is not too high.
− Check the calibration of the protection.
− Check the state of the bearings.
− Check the motor rotation speed.
− Check priming.
− On three-phase motors, check that the
direction of rotation is correct.
− Difference in suction level too high.
− The diameter of the intake pipe is
insufficient or the horizontal stretch is too
long.
− Foot valve or intake pipe blocked.
− The intake pipe or the foot valve is taking
in air.
− Check the slope of the suction pipe.
− Foot valve or impeller blocked.
− The diameter of the intake pipe is
insufficient.
− Check that the direction of rotation is
correct.
− Intake pressure too low.
− Intake pipe or pump partly blocked by
impurities.
− Leakage in the intake pipe.
− Foot valve or check valve faulty or blocked
in partly open position.
− Check that the pump and/or the pipes are
firmly anchored.
− There is cavitation in the pump.
− The pump is running above its plate
characteristics.
− The pump is not turning freely.
20
Change the motor casing with the stator or reset
any cables discharging to earth.
Provide suitable ventilation in the environment
where the pump is installed.
Calibrate at a current value suitable for the motor
absorption at full load.
Change any worn bearings.
Invert the connection of two supply wires.
Replace the intake pipe with one with a larger
diameter.
Clean the foot valve and the intake pipe.
Check the suction pipe, repeat the priming
operations.
Correct the inclination of the intake pipe.
Remove clog. Replace the impeller if weared
down.
Replace the pipe with one with a larger diameter.
Invert the connection of two supply wires.
Remove clog.
Repair or replace the faulty valve.
Reduce the intake height or check for load losses.
Reduce the flow rate.
Check the state of wear of the bearings.