Fault Finding - Grundfos Multilift MSS Montage- Und Betriebsanleitung

10. Fault finding

Warning
Before carrying out any work on lifting stations used for pumping liquids which might be hazardous to health, make
sure that the lifting station has been thoroughly flushed with clean water and that the discharge pipe has been
drained. Rinse the parts in water after dismantling. Make sure that the isolating valves have been closed.
The work must be carried out in accordance with local regulations.
Before making any connections in LC 220 or working on lifting stations, etc., make sure that the power supply has
been switched off and that it cannot be accidentally switched on.
Fault Cause
1. The pump does not run. a) No power supply.
b) The ON-OFF-AUTO selector switch is in
c) Control circuit fuses are blown.
d) The thermal switch has cut out the pump.
e) Motor/supply cable is defective.
f)
g) The power circuit board or the LED board is
h) The new DIP-switch setting does not work
2. The pump starts and a) Level sensor failure.
stops too frequently or
even if there is no
b) The level sensor is blocked.
inflow.
c) The ventilation of the inner pump housing is
3. The pump starts a) Test run 24 hours after last operation.
sometimes without
visible reason.
24
Without battery back-up:
None of the indicator lights are on.
With battery back-up:
See section 5.2 LC 220 controller.
position OFF ( ). See section 5.2.2 Control
elements and indicator lights.
Level sensor failure.
defective.
correctly.
blocked and the pump cannot build up
pressure.
Remedy
Switch on the power supply.
Push the ON-OFF-AUTO selector switch into position
ON ( ) or AUTO ( ).
Check and eliminate the cause. Replace the control
circuit fuses.
Allow the pump to cool. After cooling, the pump will
restart automatically unless LC 220 has been set to
manual restarting (see section 7.4 Setting of LC 220).
If so, push the ON-OFF-AUTO selector switch into
position OFF ( ) for a short period.
Check and replace motor and cable, if necessary.
Clean the level sensor (see section 9.2 Cleaning the
level sensor), and start up again. If the signal is still
wrong, please call Grundfos service.
Replace the power circuit board or LED board.
Switch off the power supply to the controller for 1 minute
and switch it on again (normal procedure). See section
7.4 Setting of LC 220.
Clean the level sensor (see section 9.2 Cleaning the
level sensor).
Clean the level sensor (see section 9.2 Cleaning the
level sensor).
Check the pump housing and remove any impurities.
No action necessary. It is a safety function that prevents
the shaft seal from seizing up.