Automatic Operation; Pumping To Low Water Level; Thermal Protection; Maintenance - Grundfos Unilift CC 5 Installation And Operating Instructions Manual

7.3 Automatic operation

During automatic operation, the pump with float
switch will start and stop, depending on the water
level and the float switch cable length.
Forced operation of pump with float switch
If the pump is used to drain water levels below the
stop level of the float switch, the float switch can be
kept in a higher position by fixing it to the discharge
pipe.
During forced operation, the water level should be
checked regularly to prevent dry running.

7.4 Pumping to low water level

When the suction strainer has been removed, the
pump can pump down to 3 mm.
Remove the suction strainer by inserting a screw-
driver between the pump sleeve and the suction
strainer and turning it.
Fig. 8 Removal of suction strainer
These conditions must be fulfilled:
• The pump must be placed on an even, horizontal
surface.
• The water must not contain particles which may
block the pump inlet.
• Minimum water level when the pump is started:
5 mm.
Fig. 9 Low water level

7.5 Thermal protection

If the pump is running without water, or if it is other-
wise overloaded, the built-in thermal switch will cut
out.
When the motor has cooled to normal temperature, it
restarts automatically.

8. Maintenance

Under normal operating conditions, the pump is
maintenance-free.
If the pump has been used for liquids other than
clean water, it should be flushed through with clean
water immediately after use.

8.1 Cleaning the pump

Before starting work on the pump, make
sure that the electricity supply to the pump
has been switched off and that it cannot
be accidentally switched on.
Cleaning the suction strainer
1. Switch off the electricity supply to the pump.
2. Drain the pump.
3. Loosen the suction strainer by inserting a screw-
driver between the pump sleeve and the strainer
and turning it, see fig. 8.
4. Clean and refit the suction strainer.
Cleaning the impeller
1. Switch off the electricity supply to the pump.
2. Loosen the suction strainer by inserting a screw-
driver between the pump sleeve and the strainer
and turning it, see fig. 8.
3. Remove the bottom part, see fig. 10.
Fig. 10 Removal of bottom part
4. Remove and clean the diaphragm.
5. Flush the pump with clean water to remove pos-
sible impurities between the motor and the pump
sleeve. Clean the impeller.
6. Check that the impeller can rotate freely.
7. Assemble the pump in reverse order of dis-
mantling.
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