Fault Finding; Megging - Grundfos SL1 AUTOADAPT Serie 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.
Fault
1. The pump does not run.
2. The pump operates, but
the motor stops after a
short while.
3. The pump operates at
below-standard
performance and power
consumption.
4. The pump operates, but
delivers no liquid.

12.1 Megging

Warning
Megging of SL1 and SLV AUTO
pumps is not allowed as the built-in
electronics may be damaged.
24
Cause
a) The dry-running sensors are not
covered by the liquid.
b) Three-phase pumps only:
The pump is connected to the
power supply with a wrong phase
sequence.
c) The fuses in the electric
installation have blown.
d) Supply failure, short-circuit or
fault in the cable or motor
winding.
e) Fault in motor electronics.
f) Deposits on level or dry-running
sensors.
a) The impeller is 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) The outlet pipe is partly blocked
by impurities.
b) The valves in the outlet pipe are
partly closed or blocked.
a) The outlet valve is closed or
blocked.
b) The non-return valve is blocked.
c) Air in the pump.
ADAPT
Warning
Observe all regulations applying to pumps
installed in potentially explosive
environments.
Make sure that no work is carried out in
potentially explosive atmosphere.
Remedy
After power-on: Allow the liquid level
to rise until the dry-running sensors
are covered with liquid.
Interchange L1 and L2.
Replace the blown fuses. If the new
ones blow too, check the electric
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 supply voltage is
within the range.
Reduce the liquid temperature.
Dilute the liquid.
Clean the outlet pipe.
Check and clean or replace the
valves, if necessary.
Check the outlet valve, and possibly
open and/or clean it.
Clean the non-return valve.
Vent the pump.