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9. Pump control
If the pit is equipped with an Auto
Note
controlled pump, an external level controller is
not needed.
When installing the level switches, observe the following points:
•
To prevent air intake and vibrations in the pump, the stop level
switch must be fitted in such a way that the pump is stopped
before air is sucked into the pump.
•
In the case of 1-pump operation, the start level switch should
be installed in such a way that the pump is started at the
required level; however, the pump must always be started
before the liquid level reaches the lower edge of the bottom
inlet pipe.
•
In the case of 2-pump operation, the start level switches
should be installed in such a way that pump 2 is started before
the liquid level reaches the lower edge of the bottom inlet pipe,
and so that pump 1 is started correspondingly earlier.
•
The high-level alarm switch should always be installed about
100 mm above the start level switch; however, the alarm must
always be given before the liquid level reaches the inlet pipe.
For further settings, see the installation and operating instructions
for the pump controller selected.
9.1 Start and stop levels
The effective volume of the pit must be so large that the number
of starts does not exceed the maximum permissible number.
See the installation and operating instructions for the pump.
9.2 Installation of pump controller
See the installation and operating instructions for the pump
controller.
9.3 Installation of level controllers
9.3.1 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 for the
pump.
A
B
Fig. 28 Adjustment of float switches
A
Min. 300 mm
B
50 to 100 mm
C
Deactivation range 110 mm
12
Caution
ADAPT
The pit inlet must not be located within the area shown in fig. 29,
as it will disturb the function of float switches.
Fig. 29 Location of inlet
9.3.2 Electrodes
If electrodes are used for level control, note that the electrodes
come in a standard length (1 m). When they are installed, their
lengths must therefore be adjusted so that they are activated at
the correct levels.
If possible, bend the electrodes away from each other so that
paper and similar items cannot get stuck between the electrodes
and disturb the signal.
When they have been shortened to the desired length, strip 10 to
15 mm of the lower end of the electrodes.
The electrodes come with a 10 m cable.
Fig. 30 Electrodes in a pit with one pump
C
Fig. 31 Electrodes in a pit with two pumps
Distance B must not be too big as otherwise the
float switch may get stuck in other parts of the
installation.
200
200
Alarm: 32
Start: 22
The stop level
depends on the
pump type
Common: 11
Alarm: 42
Start
Start
The stop level
depends on the
pump type
Common: 11
: 32
2
: 22
1
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