Adjustment Of Cable Length For Float Switch; Operation; Self-Venting; Manual Operation - Grundfos Unilift CC 5 Instrucciones De Instalación Y Funcionamiento

9.4 Adjustment of cable length for float
switch
The difference in level between start and stop can be
adjusted by changing the free cable length between
the float switch and the pump handle.
• An increased free cable length will result in fewer
starts/stops and a large difference in level.
• A reduced free cable length will result in more
frequent starts/stops and a small difference in
level.
In order that the float switch can start and stop the
pump, the free cable length must be min. 3.9"
(100 mm) and max. 7.9" (200 mm).
Start
Fig. 7 Start/stop levels. See table below.
Cable length (L)
min. 3.9"
(100 mm)
Pump type
Start
[inch
(mm)]
13.8
Unilift CC 5
(350)
13.8
Unilift CC 7
(350)
15.2
Unilift CC 9
(385)

10. Operation

10.1 Self-venting

A vent valve is built into the pump handle. The valve
allows air to escape from the pump in case the free
air flow through the discharge pipe is blocked.
Once the pump is vented, the valve normally closes.
If the pump sucks air or water with a high air content,
the valve may leak a mixture of air and water. This is
no fault but a natural consequence of the opening
and closing of the valve.
8
L
Stop
Cable length (L)
max. 7.9"
(200 mm)
Stop Start Stop
[inch [inch [inch
(mm)] (mm)] (mm)]
4.5 15.75 2.2
(115) (400) (55)
4.5 15.75 2.2
(115) (400) (55)
5.9 17 3.5
(150) (435) (90)

10.2 Manual operation

The pump is started and stopped by an external
switch.
To eliminate the risk of dry running, the water level
should be checked regularly during operation. This
can for instance be done by an external level
controller.
In order that the pump can self-prime when started,
the water level must be at least 1" (25 mm).
The pump can pump down to 0.8" (20 mm) water
level.
For pumping to low level, see section 10.4.

10.3 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.

10.4 Pumping to low water level

When the suction strainer has been removed,
the pump can pump down to 0.12" (3 mm).
Remove the suction strainer by inserting a
screwdriver 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:
0.2" (5 mm).
Fig. 9 Low water level