Fault Finding - Grundfos SEG AUTOADAPT Montage- Und Betriebsanleitung

12. Fault finding

Warning
Before attempting to diagnose any fault, make sure that the fuses have been removed or the mains
switch has been switched off. Make sure that the power supply cannot be accidentally switched on.
All rotating parts must have stopped moving.
Warning
All regulations applying to pumps installed in potentially explosive environments must be observed.
Make sure that no work is carried out in potentially explosive atmosphere.
Fault
1. The pump does not run.
2. The pump runs, but
stops after a short while.
3. The pump runs at
below-standard
performance and power
consumption.
4. The pump runs, but
delivers no liquid.
5. The pump is seized up.
Cause
a) The dry-running sensors are not
covered by liquid.
b) Three-phase pumps only:
The pump is connected to the
power supply with a wrong phase
sequence.
c) Fuses in electrical installation
blown.
d) Supply failure, short circuit,
earth-leakage fault in cable or
motor winding.
e) Fault in motor electronics.
f) Deposits on level or dry-running
sensors.
a) Impeller blocked by impurities.
Increased current consumption in
all three phases.
b) Increased current consumption
due to large voltage drop.
c) Too high liquid temperature.
d) Too high liquid viscosity.
a) Discharge pipe partly blocked by
impurities.
b) Valves in the discharge pipe
partly closed or blocked.
a) Discharge valve closed or
blocked.
b) Non-return valve blocked.
c) Air in pump.
a) Grinder system is worn.
Remedy
After power-on: Allow the liquid level
to rise until the dry-running sensors
are covered with liquid.
Interchange L1 and L2.
Replace blown fuses. If the new ones
blow too, check the electrical
installation and the submersible drop
cable.
Have the cable and motor checked
and repaired by a qualified
electrician.
Have the motor checked and repaired
by a Grundfos service engineer.
Clean the sensor(s).
Clean the impeller.
Check that the power supply is within
the specified range.
Reduce the liquid temperature.
Dilute the liquid.
Clean the discharge port.
Check and clean or replace the
valves, if necessary.
Check the discharge valve, and open
and/or clean it, if necessary.
Clean the non-return valve.
Vent the pump.
Replace the grinder system.
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