Grundfos LC 221, Installation And Operating Instructions Manual

Page: 28 / 796

English (GB)
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11. 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 the LC 221 or work on lifting stations, etc., it must be ensured that the power
supply has been switched off and that it cannot be accidentally switched on.
Fault Cause Remedy
1. The pump(s) does/do
not run.
a) No power supply.
None of the indicator lights are on.
With battery back-up:
See section 5.2 LC 221 controller .
Switch on the power supply or wait until the power cut is
over. During the power cut, drain the collecting tank with
diaphragm pump.
b) The ON-OFF-AUTO selector switch is in
position OFF ( ), see section 6. Operating
LC 221 controller .
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 motor-protective circuit breaker has cut
out the pump (only relevant if a
motor-protective circuit breaker has been
installed). The pump symbol in the display is
flashing and the red indicator light for fault is
flashing. The fault indication in the display is
RELAY and the fault code is F018.
Check the pump and tank as well as the setting of the
motor-protective circuit breaker. If the pump is blocked,
remove the blockage. If the setting of the
motor-protective circuit breaker is wrong, readjust it
(compare the setting with the nameplate).
e) Motor/supply cable is defective or the
connections have become loose.
Check motor and supply cable. Replace cable or
retighten connections if necessary.
f) The fault indication in the display is
SENSOR and in the fault code is F005
and/or F006. Clean the level sensor (see section 10.4 Cleaning the
level sensor ), and start up again. Check the cable and
the connection on the controller board. If the signal is
still wrong, please call Grundfos service.
g) The module power circuit board or the LCD
board is defective.
Replace the PCB or LCD board.
2. The pump(s) is/are
starting/stopping too
frequently and even if
there is no inflow.
a) The level sensor fails. The sensor gives
wrong signal.
Clean the level sensor
(see section
10.4 Cleaning the level sensor ).
b) The operating time protection is activated,
the pump and time symbols are flashing, the
red LED is flashing and the display indicates
fault code F011 and/or F012. If the pump
runs longer than 3 minutes, a protection
program of the controller will stop the pump
for 3 minutes and the other pump will take
over. At the next start impulse, the first
pump will be activated again. If the venting
problem persists, the pump will be stopped
after 3 minutes and so on.
Note: Normal operating times are up to
60 seconds depending on duty point and
effective tank volume.
Check that the discharge valve is open. Check the
venting of the pump housing. If blocked clean the vent
hole. See fig.
33 .
c) The thermal switch has cut out the pump.
The pump and thermal switch symbols on
the display are flashing, and the red
indicator light for fault is permanently on.
The fault indication in the display is TEMP
and in the fault code is F005 and/or F006.
Allow the pump to cool. After cooling, the pump will
restart automatically unless the LC 221 has been set to
manual restarting. See section
8.4 Setting of LC 221 .
If so, the ON-OFF-AUTO selector switch must be
pushed into position OFF ( ) for a short period.
Check the inflow parameters and the non-return valve.
The risk is low, but if the non-return valve flap is leaky,
liquid in the discharge pipe can flow back.
A high number of starts without cooling time in between
over a longer period can cause thermal cut-out.
Consider S3 duty. See section
12. Technical data .
See also section 10.4 Cleaning the level sensor .
3. One 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 sealing from seizing up.