Lowara NSC2, Installation, Operation And Maintenance Manual

Page: 22 / 348

7.3 The electric pump starts, but
the thermal protector trips or the
fuses blow immediately after
Cause Remedy
The power supply ca-
ble is damaged.
Check the cable and re-
place as necessary.
The thermal protection
or fuses are not suited
for the motor current.
Check the components
and replace as necessary.
The electric motor is
short circuit.
Check the components
and replace as necessary.
The motor overloads. Check the operating condi-
tions of the pump and re-
set the protection.
7.4 The electric pump starts, but
the thermal protector trips or the
fuses blow a short time after
Cause Remedy
The electrical panel is situ-
ated in an excessively
heated area or is exposed
to direct sunlight.
Protect the electrical
panel from heat source
and direct sunlight.
The power supply voltage
is not within the working
limits of the motor.
Check the operating
conditions of the motor.
A power phase is missing. Check the
• power supply
• electrical connec-
tion
7.5 The electric pump starts, but
the thermal protector trips a varying
time after
Cause Remedy
There are foreign ob-
jects (solids or fibrous
substances) inside the
pump which have jam-
med the impeller.
Contact the local sales and
service representative.
The pumps delivery
rate is higher than the
limits specified on the
data plate.
Partially close the on-off
valve down stream until the
delivery rate is equal or
less than the limits speci-
fied on the data plate.
The pump is overload-
ed because it is pump-
ing liquid that is too
dense and viscous.
Check the actual power re-
quirements based on the
characteristics of the
pumped liquid and replace
the motor accordingly.
The motor bearings
are worn.
Contact the local sales and
service representative.
7.6 The electric pump starts, but
the system's general protection is
activated
Cause Remedy
A short circuit in the electri-
cal system.
Check the electrical
system.
7.7 The electric pump starts, but
the system's residual current device
(RCD) is activated
Cause Remedy
There is an ground
(earth) leakage.
Check the insulation of the
electrical system components.
7.8 The pump runs but delivers too
little or no liquid
Cause Remedy
There is air inside
the pump or the pip-
ing.
• Bleed the air
The pump is not
correctly primed.
Stop the pump and repeat the
prime procedure.
If the problem continues:
• Check that the mechanical
seal is not leaking.
• Check the suction pipe for
perfect tightness.
• Replace any valves that
are leaking.
The throttling on the
delivery side is too
extensive.
Open the valve.
Valves are locked in
closed or partially
closed position.
Disassemble and clean the
valves.
The pump is clog-
ged.
Contact the local sales and
service representative.
The piping is clog-
ged.
Check and clean the pipes.
The rotation direc-
tion of the impeller
is wrong .
Change the position of two of
the phases on the terminal
board of the motor or in the
electric control panel.
The suction lift is
too high or the flow
resistance in the
suction pipes is too
great.
Check the operating condi-
tions of the pump. If necessa-
ry, do the following:
• Decrease the suction lift
• Increase the diameter of
the suction pipe
7.9 The electric pump stops, and
then rotates in the wrong direction
en - Original instructions
22