Systems For Parallel Operation With 4 Float Switches; Electrical Connection; Setting - Grundfos LCD 108 Installations- Und Bedienungsanleitung

5. Systems for parallel operation with 4 float
switches
Description (see also page 144
The pumps are controlled by the liquid level in the pit.
• The float switch, pos. 2, starts the first pump.
• The float switch, pos. 3, starts the next pump.
• The float switch, pos. 1, stops both pumps after expiration of
the "stop delay" (can be set).
• The pumps operate alternately.
• The top float switch, pos. 4, activates the high-level alarm.
Warning
Before starting any work on pumps used to pump
liquids which could be constituted as being
hazardous to health, thorough cleaning/venting
of pumps, pits, etc. must be carried out
according to local regulations.
Before making any connections in the LCD 108 or
work on pumps, pits, etc., it must be ensured that
the electricity supply has been switched off and
that it cannot be accidentally switched on.

5.1 Electrical connection

Parallel operation with 4 float switches, pages
Warning
Before starting work on the system, switch off
the supply voltage and lock the mains switch in
position 0.
Any external voltage connected to the system
must be switched off before work is started.
Fig. 3 on page 144.
The figures show all electrical connections required to connect
the LCD 108 for direct-on-line starting, parallel operation with
4 float switches.
Fig. 4 on page 145.
The figure shows all electrical connections required to connect
the LCD 108 for star-delta starting, parallel operation with 4 float
switches.
Warning
The LCD 108 must be connected in accordance
with the rules and standards in force for the
application in question.
The operating voltage and frequency are marked on the controller
nameplate. Make sure that the controller is suitable for the
electricity supply on which it will be used.
All cables/wires must be fitted through the Pg cable entries and
gaskets (IP65).
Maximum back-up fuse is stated on the controller nameplate.
If required according to local regulations, an external mains
switch must be installed.
If the PTC resistance/thermal switch of the motor
is connected, the factory-fitted short-circuit
jumper must be removed (terminals T11-T21,
Caution
T12-T22). For correct installation of PTC resistor/
thermal switch, see the installation and operating
instructions of the pump.
Single-phase motors must be connected to an external operating
capacitor and in certain cases also to a starting capacitor.
Further details can be found in the installation and operating
instructions for the pump in question.
12
or 145):
144 and 145.
Warning
Float switches placed in an explosion hazard
area must be connected via an EEx barrier, e.g.
Grundfos number 96440300.
The EEx barrier must not be installed in the
explosion hazard area.
Equipment used in explosion hazard areas must
in each individual case have been approved for
this particular application. Furthermore, the
cables into the explosion hazard area must be
laid in accordance with local regulations.
Float switches of the same type as Grundfos
product number 96003332 or 96003695, i.e. float
switches with gold-plated contacts suitable for
Note
low voltages and currents (40 V / 100 mA), must
be used. All EEx-approved float switches are also
suitable.
The float switches must be connected as NO contacts, i.e. brown
and black leads, when float switches, Grundfos product number
96003332 or 96003695, are used.
Key to the symbols in fig. 3 on page
page 145:
Pos. Description
1 Float switch for common stop.
2 Float switch for start of the first pump.
3 Float switch for start of the next pump.
4 Float switch for high-level alarm.

5.2 Setting

Parallel operation with 4 float switches, pages
The module CU 212 has a 10-pole DIP switch in the bottom right
corner, see fig. 9.
The controller must be off circuit to ensure the
Caution
correct configuration during start-up after
change of the DIP switch setting.
The DIP switch setting offers the following possibilities:
• selection of starting delay and automatic test run (switch 4),
• setting of stop delay (switches 5, 6 and 7),
• selection of automatic alarm resetting (switch 9),
• selection of automatic restarting (switch 10).
Fig. 9
Set the DIP switch as shown in fig. 9.
Each individual switch (1 to 10) of the DIP switch can be set to
position OFF or ON.
144 and fig. 4 on
Terminal
number
11-12
21-22
31-32
41-42
144 and 145.