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10.3 Float switches
If float switches have been selected, they can be fitted on a tube
which can be lifted out of the pit. This ensures easy adjustment of
float switches.
Note that the bottom float switch (stop) must stop
the pump before the level in the pit falls below
Note
the minimum level of the pump. See the
installation and operating instructions of the
pump.
A
B
Fig. 22 Adjustment of float switches
A
Min. 300 mm
B
50 to 100 mm
C
Deactivation range 110 mm
Distance B must not be too big as otherwise the
Caution
float switch may get stuck in other parts of the
installation.
The pit inlet must not be located within the area shown in fig. 23,
as it will disturb the function of float switches.
200
Fig. 23 Location of inlet
C
200
10.4 Rod electrodes
If rod electrodes are used for level measurement, note that the
rods come in standard length (1 m). When they are installed, their
length must therefore be adjusted so that they are activated at
the correct levels.
If possible, bend the rods away from each other so that paper and
similar items cannot get stuck between the rods and disturb the
signal.
When they have been shortened, 10 to 15 mm of the lower end of
the rods must be stripped.
The rods come with 10 metres of cable.
Fig. 24 Rod electrodes in a pit with one pump
Fig. 25 Rod electrodes in a pit with two pumps
10.5 Air bells
Air bells are pulse generators for the pressure switches of the
controller and function by means of pneumatic pressure changes.
The pressure changes when the liquid level in a pickup changes.
The air bells are connected to the pressure switches of the
controller by means of hoses.
CU 211
Fig. 26 Air bells in a pit with one pump
10.6 Pressure transducer
If a pressure transducer is used, it should be installed in a riser
pipe in order to prevent contamination and deposits.
10.7 Other types of level control equipment
See the installation and operating instructions of the equipment.
Alarm: 32
Start: 22
The stop level
depends on the
pump type.
Common: 11
Alarm: 42
Start
: 32
2
Start
: 22
1
The stop level
depends on the
pump type.
Common: 11
CU 211
13
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