Impurities In The Water; Minimum Flow Rate; Built-In Functions; Resetting The Pump - Grundfos SQ Serie Instrucciones De Instalación Y Funcionamiento

• To ensure the necessary cooling of the motor, the
pump should never be set so low that it gives no
water.
If the flow rate suddenly falls, the reason might be
that the pump is pumping more water than the well
can yield. The pump must immediately be stopped
and the fault corrected.

11.2 Impurities in the water

If there are impurities in the water, the valve should
be opened gradually as the water becomes clearer.
The pump should not be stopped until the water is
clean, otherwise the pump parts and the check valve
may become clogged.
When the water is clean, the valve should be fully
opened.

11.3 Minimum flow rate

To ensure the necessary cooling of the motor, the
pump flow rate should never be set to a value lower
than 0.2 gpm.
If the flow rate suddenly falls, the reason might be
that the pump is pumping more water than the well
can yield. The pump must immediately be stopped
and the fault corrected.
WARNING: The pump's dry-running protection is
effective only within the recommended duty range of
the pump.
Note: Do not let the pump run against a closed dis-
charge valve for more than 5 minutes. When the dis-
charge valve is closed, there is no cooling flow and
there is a risk of overheating in motor and pump.

11.4 Built-in functions

The motor incorporates an electronic unit which
functions as follows:
• In case of overload, the built-in overload protec-
tion will stop the pump for 5 minutes. After that
period, the pump will attempt to restart.
• If the pump has been stopped as a result of dry
running, it will start automatically after 5 minutes.
• If the pump is restarted and the well has not
recovered, the pump will stop after 30 seconds.

11.5 Resetting the pump

Switch off the electricity supply for 1 minute.

11.6 MS 3 motors

Note: All MS 3 motors are factory-set to detect dry-
running conditions.
Check that the combination of pump and motor cor-
responds to the data on page 35.

11.7 MSE 3 motors

Note: All MSE 3 motors are factory-set to detect dry-
running conditions. However, if the maximum pump
speed setting is changed, the dry-running stop value
must also be changed. Please refer to either the
CU 300 or CU 301 I&O for instructions on this proce-
dure.

11.8 Maintenance and service

The pumps are normally maintenance-free.
Deposits and wear may occur.
For that purpose, service kits and service tools are
available from Grundfos.
The pumps can be serviced at a Grundfos service
center.

12. Assembly of pump and motor

To assemble pump end and motor, proceed as
follows:
1. Place the motor horizontally in a vice and tighten
it, see fig. 11.
2. Pull the pump shaft out to the position shown in
fig. 10.
Fig. 10 Pump shaft position
3. Grease the motor shaft end with the grease
supplied with the motor.
4. Screw the pump end on the motor (55 Nm).
Note: The pump shaft must engage with the
motor shaft.
A spanner may be used on the clamping faces of
the pump end, see fig. 11.
5. Fit the cable guard as described in section 7.
Use pump vice here
Fig. 11 Pump in vice
0.5 hp: L = 4.7".
0.75 hp: L = 4.0".
1.0 hp: L = 2.6".
1.5 hp: L = 2.6".
When pump end and motor have been assembled
correctly, there must be no clearance between pump
end and motor.
To disassemble, reverse procedure.
L
6.14"
9