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16
9. Fault finding the product
Before attempting to diagnose any fault, read and
observe the safety instructions in section
.
For pumps with a sensor, start fault finding
by checking the status on the GU01 or
GU02 front panel. See installation and
operating instructions for GU01 or GU02.
DANGER
Electric shock
Death or serious personal injury
- Before starting any work on the product,
make sure that the power supply has
been switched off and that it cannot be
accidentally switched on.
Fault
Cause
Remedy
The motor does not start,
the fuses blow or the
motor protector trips
immediately.
Caution:
Do not try to
start again.
1.
Power supply failure, short circuit
or earth leakage in the cable or
the motor winding.
Have the cable and motor checked and
repaired by a qualified electrician.
2.
The fuses blow due to use of
wrong type of fuse.
Fit fuses of the correct type.
3.
The impeller is blocked by
impurities.
Clean the impeller.
4.
Level pickup, float switch or
electrode is out of adjustment or
defective.
Check the level pickups, float switches or
electrodes.
5.
Motor phase malfunction.
Inspect the motor and the connections.
The pump operates, but
the motor protector trips
after a short while.
1.
The setting of the thermal relay in
the motor protector is low.
Set the relay in accordance with the
specifications on the pump nameplate.
2.
Increased current consumption
due to large voltage drop.
Measure the voltage between two motor
phases. Tolerance: - 5 %/+ 5 %.
3.
The impeller is blocked by
impurities.
Clean the impeller.
4.
The direction of rotation is wrong. Check the direction of rotation and possibly
interchange any two phases in the power
supply. See section
The thermal switch of the
pump trips after a short
while.
1.
The liquid temperature is too high.
Inadequate cooling.
Improve cooling or lower the liquid
temperature.
2.
The viscosity of the pumped liquid
is too high.
Dilute the pumped liquid.
3.
Fault in the electrical connection.
(Y-connection of pump to D-
connection results in considerable
undervoltage).
Check and correct the electrical
connection.
The pump operates at
below-standard
performance and power
consumption.
1.
The impeller is blocked by
impurities.
Clean the impeller.
2.
The direction of rotation is wrong. Check the direction of rotation and possibly
interchange any two phases in the power
supply. See section
The pump operates, but
gives no liquid.
1.
There is air in the pump.
Vent the pump twice.
2.
The outlet valve is closed or
blocked.
Check the outlet valve and open and/or
clean it if necessary.
3.
The non-return valve is blocked.
Clean the non-return valve.
The pump is clogged.
1.
The liquid contains large particles. Select a pump with a larger size of
passage.
2.
A float layer has formed on the
surface.
Install a mixer in the pit.