Grundfos Multilift MSS, Installation And Operating Instructions Manual

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English (GB)
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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 outlet 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 Remedy
1. The pump does not run. a) No power supply.
Without battery backup:
None of the indicator lights are on.
With battery backup:
See section 5.2 LC 220 controller .
Switch on the power supply.
b) The ON-OFF-AUTO selector switch is in
position OFF ( ). See section 5.2.2 Control
elements and indicator lights .
Push the ON-OFF-AUTO selector switch into position
ON ( ) or AUTO ( ).
c) Control circuit fuses are blown. Check and eliminate the cause. Replace the control
circuit fuses.
d) The thermal switch has cut out the pump. 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.
e) Motor/supply cable is defective. Check and replace motor and cable, if necessary.
f) The power circuit board or the LED board is
defective. Replace the power circuit board or LED board.
g) The new DIP-switch setting does not work
correctly.
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 .
2. The sensor signal is out
of range.
All pumps are started
and high-level alarm is
on.
a) Not all outlet valves are open. Open all outlet valves.
b) There is a blockage in the tank or pump. Remove the blockage.
c) The pump is not vented correctly. The pump
cannot build up pressure.
Remove any blockage from the vent hole underneath
the pump.
d) The lifting station is undersized. Recalculate the inflow parameters and compare the
result with the tank volume and pump performance. If
you need a new product, contact the nearest Grundfos
sales company.
3. The pump starts and
stops too frequently
even if there is no
inflow.
a) The level sensor is blocked. Clean the level sensor (see section 9.2 Cleaning the
level sensor ).
b) The ventilation of the inner pump housing is
blocked and the pump cannot build up
pressure.
Check the pump housing and remove any impurities.
4. The pump starts
sometimes without
visible reason.
a) Test run 24 hours after last operation. No action necessary. It is a safety function that prevents
the shaft seal from seizing up.