Thermal Switches; Moisture Switches; Electrical Connection; Start-Up - Grundfos S1 Serie Instrucciones De Instalación Y Funcionamiento

When installing the level switches, the following points should be
observed:
1. To prevent air intake and vibrations in submerged pumps, the
stop level switch must be fitted in such a way that the pump
is stopped before the liquid level is lowered below the top of
the pump housing.
As a principal rule for pumps in dry installation, the lowest stop
level must be at least 20 cm above the opening of the suction
pipe, see fig. 7.
2. 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
bottom inlet pipe to the pit.
3. The high-level alarm switch, if installed, should always be
installed about 10 cm above the start level switch; however,
alarm must always be given before the liquid level reaches the
inlet pipe to the pit.
Note: The pump controller must not be installed in potentially
explosive environments.
Pumps installed in potentially explosive atmosphere
must always be filled with the liquid to be pumped.
An additional level switch must be installed to ensure
that the pump is stopped in case the stop level switch
is not operating.

4.5 Thermal switches

All motors are equipped with thermal switches as standard.
Three bimetallic thermal switches are built into the stator windings,
and a contact will open in case of overtemperature, i.e. 150°C.
The supply voltage to the thermal switches must be 12-230 VAC.
The thermal switches are connected to the monitoring cable, see
section 5. Electrical connection, and must be connected to the
safety circuit of the separate pump controller.
Note: The motor starter of the pump controller must include a cir-
cuit which automatically disconnects the electricity supply in case
the protective circuit for the pump is opened.
The installer/user should provide an automatic device
which disconnets the electricity supply in case the
thermal switches or the moisture switches are not
operating.

4.6 Moisture switches

All motors are equipped with moisture switches as standard.
Non-explosion-proof pumps have one moisture switch, which is
fitted in the chamber below the motor top cover.
Explosion-proof pumps have two moisture switches connected
in series, which are fitted in the chamber below the motor top
cover.
The moisture switch is non-reversing and must be replaced after
use.
The moisture switches are connected in series with the thermal
switches and connected to the monitoring cable, see section
5. Electrical connection, and must be connected to the safety cir-
cuit of the separate pump controller.
Note: The motor starter of the pump controller must include a cir-
cuit which automatically disconnects the electricity supply in case
the protective circuit for the pump is opened.

5. Electrical connection

The electrical connection should be carried out in accordance
with local regulations.
The supply voltage and frequency are marked on the pump
nameplate.
The voltage tolerance must be within ±10% of the rated voltage.
Make sure that the motor is suitable for the electricity supply
available at the installation site.
The pump must be connected to an external mains
switch with a contact separation of at least 3 mm in
each pole.
The pump must be connected to a motor starter.
The wiring diagrams for direct-on-line starting and star-delta start-
ing are shown in fig. 8 and fig. 9, respectively.
P1 and P2 are connected in series with the thermal switches and
the moisture switches.
P2 P1
Direct-on-line
starting
Fig. 8
P2 P1
Star-delta
starting
Fig. 9
The top cover of explosion-proof pumps is provided
with an external earth terminal to ensure the connec-
tion to earth.
Before installation and the first start-up of the pump,
the cable condition should be checked visually to
avoid short circuits.

6. Start-up

Before manual starting or changeover to automatic
control, make sure that no persons are working on or
near the pump.
Proceed as follows:
1. Remove the fuses or switch off the mains switch.
2. Check the oil level in the oil chamber. See section 7.1 Oil
check and oil change.
3. Check whether the impeller can rotate freely.
4. Check whether the monitoring units, if used, are operating
satisfactorily.
5. Make sure that the pump is submerged in the liquid.
For pumps in dry installation, it must be ensured that there is
liquid in the pit.
Make sure that the pump has been filled with the
liquid to be pumped.
Pumps in dry installation must be vented by means of
the vent plug in the pump housing.
6. Open the isolating valves, if fitted.
7. Check whether the system has been filled with liquid and
vented.
8. Check the setting of the level switches.
9. Start the pump and check the pump operation for abnormal
noise or vibrations.
L1 L2 L3 PE
W2 U2 V2
U1 V1 W1 PE
M
3
L1 L2 L3 PE
W2 U2 V2
U1 V1 W1 PE
M
3
11