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10. Troubleshooting
Malfunction
Cause
Elimination
The pump does not start
when being switched on.
No voltage.
Check the voltage.
The impeller jams.
Check both the impeller and
the fan blade of the motor for
easy movement.
The magnetic coupling
disengages.
The relative density
and/or viscosity of the
fluid is too high.
Reduce the delivery rate; use
a stronger magnetic coupling
and a more powerful motor.
Reduce the impeller diameter.
The pump was switched
off, then switched on
again before the rotor
stopped completely.
Make sure that the rotor has
stopped completely before you
switch on the pump again.
The impeller jams.
Open the pump head to
eliminate the obstruction.
There is a loud drumming
flow noise.
Cavitation.
Reduce the delivery rate of the
discharge line.
Increase the suction line
diameter.
Cool down the fluid.
Increase the NPSH of the
system.
There is a loud flow noise.
The starting delivery rate is
insufficient.
Wrong direction of
rotation.
Correct the motor’s direction
of rotation.
There is air in the
suction line or pump
housing.
Deaerate the piping and the
housing.
Since the pump is non-
self-priming, both the
suction line and the
pump housing must be
filled with fluid.
Fill the suction line and
housing with fluid
The delivery rate is too
low.
Wrong direction of
rotation.
Correct the direction of
rotation.
The suction and/or
discharge line is
clogged.
Clear the line, open the valves.
Cavitation.
Increase the NPSH of the
system, see Cavitation above.
There is air in the pump. Check the suction line and seal
it.