A. Check the presence of all phases in the
terminal box.
B. Check for possible open or dirty contacts
in the protection.
C. Check for possible faulty motor isolation
by checking the phase resistance and
the isolation to ground.
D. The pump works above the working
point for which it has been conceived.
E. The protection activation values are
erroneous.
F. The viscosity or density of the liquid
pumped are different from those used in
the project phase.
A. If not, reset the missing phase.
B. Replace or clean the component.
C. Replace the motor box with stator or
reset the ground cables.
D. Establish the operating point according
to the characteristic curves of the
pump.
E. Check the values established in the
motor protection: modify them or
replace the component if necessary.
F. Reduce the flow with a door valve on
the supply side or install a larger motor.
4. The (exterior) protection of the
motor is immediately activated
after starting.
A. Make sure the ambient temperature is
not too high
B. Check the protection calibration.
C. Check the state of the bearings
D. Check the motor speed rotation
A. Suitably ventilate the premises where
the pump is installed.
B. Calibrate with a current value suitable
for the motor absorption at full load.
C. Replace worn bearings.
5. The motor protection is activated
too frequently.
A. The pump has not been primed
correctly.
B. Check the direction of the three-phase
motor rotation.
C. Suction level too high.
D. Suction pipe too narrow or too long.
E. Blocked base valve.
A. Fill the pump and the suction with
water and purge.
B. Invert two supply cables.
C. Consult point 8 of the instructions for
“Installation”.
D. Replace the suction pipe with a wider
one.
E. Clean the base valve.
6. The pump fails to supply
A. The suction pipe or the base valve sucks
in air.
B. The negative inclination of the suction
pipe enhances the formation of air
bubbles
A. Eliminate the phenomenon by carefully
controlling the suction pipe and
repeating the priming operations.
B. Correct the inclination of the suction
pipe.
7. The pump fails to prime
Faults
Checks
Solutions
ENGLISH
16
manual V-nox 2010_A5 21/12/10 11:00 Página 18
