18
Pump is vibrating or noisy. Pump does not work in its
working range.
Select another pump or
adjust the system to work
within its working range.
Pump is standing on an
uneven surface.
Level the surface.
Malfunction.
Internal blockage in the
pump.
Have the pump inspected
by a certified company.
Pump does not start.
No voltage on the power
terminal.
Check the power supply.
•
Circuit
•
Main switch
•
Fuses
Check the motor safety
relay
•
Earth leakage switch
•
Protective relay
Thermal motor safety
switch triggered.
Reset the thermal motor-
safety. Contact the sup-
plier, if this problem occurs
more often.
Check if the correct value
is set. Find the correct
value (I
nom
) on the motor
type plate.
The motor is running, but
the pump does not work.
The coupling between
pump- and motor shaft is
loose (when applicable).
Tighten the connecting
screws to the required
torque.
The pump shaft is broken. Contact the supplier.
Pump supplies insufficient
capacity and/or pressure.
Outlet and/or inlet shut-off
valve is closed.
Open both shut-off valves.
There is air in the pump.
Vent the pump.
The suction pressure is
insufficient.
Increase the suction pres-
sure.
Pump rotates in the wrong
direction.
Change over L1 and L2 of
the three phase supply.
The suction line has not
been vented.
Vent the suction line.
Air bubble in the suction
line.
Install the suction line with
pump end higher than the
other end.
Pump sucks air because
of leakage in the suction
line.
Repair the leakage.
Water flow too low. So air
bubbles clog up in the
pump.
Make sure the flow
increases or use a smaller
pump.
The diameter of the suc-
tion line is too small.
Increase the diameter of
the suction line.
Capacity of water meter in
the supply line is too
small.
Increase the capacity of
the water meter.
Foot valve blocked.
Clean the foot valve.
The impeller, the diffuser
or stage is blocked.
Clean the inside of the
pump.
O-ring between impeller
and diffuser is gone.
Replace the O-rings.
O-ring not resistant to the
medium to be pumped.
Replace O-ring by an O-
ring with better resistance.
Problem
Possible cause
Possible solution
Checkpoints
