Installation Depth; Startup And Operationstarting Up The Product; Startup - Grundfos SP Series Installation And Operating Instructions Manual

7.9 Installation depth

The dynamic water level must always be above the suction
interconnector of the pump. See section
requirements and fig. 27.
Minimum inlet pressure is indicated in the NPSH curve for the
pump. The minimum safety margin must be 1 metre head.
We recommend that you install the pump so that the motor part is
above the well screen in order to ensure optimum cooling. See
section 5.5 Liquid temperatures/cooling Liquid temperatures and
motor cooling).
When the pump has been installed to the required depth, the
installation must be finished by means of a borehole seal.
Slacken Loosen the straining wire so that it becomes unloaded
and lock it to the borehole seal by means of wire locks.
For pumps fitted with plastic pipes, the expansion of
the pipes when loaded must be taken into
consideration, when deciding on the installation
depth of the pump.
8. Startup and operationStarting up the product
DANGER
Electric shock
Death or serious personal injury
- The pump must be connected to protective earth.
- Switch off the power supply before you start any
work on the product.
- Make sure that the power supply cannot be
accidentally switched on.

8.1 Startup

When the pump has been connected correctly and it is
submerged in the liquid to be pumped, it must be started with the
outlet valve closed off to approximately 1/3 of its maximum
volume of water.
Check the direction of rotation as described in section
6.6.4 Checking the direction of
If there are impurities in the water, open the valve gradually as
the water becomes clearer. Do not stop the pump until the water
is completely clean, as otherwise the pump parts and the
non-return valve may become blocked.
As the valve is being opened, check the drawdown of the water
level to ensure that the pump always remains submerged.
The dynamic water level must always be above the suction
interconnector of the pump. See section
requirements and fig. 27.
5.3 Positional
rotation.
5.3 Positional
L3
L2
L1
Fig. 27 Comparison of various water levels
L1: Minimum installation depth below dynamic water level. We
recommend minimum 1 metre0.5m or according to NPSH -
curve for the relevant pump.
L2: Depth to dynamic water level.
L3: Depth to static water level.
L4: Drawdown. This is the difference between the dynamic and
the static water levels.
L5: Installation depth.
If the pump can pump more than yielded by the well, we
recommend that you install the Grundfos MP 204 motor protector
or some other type of dry-running protection.
If no water level electrodes or level switches are installed, the
water level may be drawn down to the suction interconnector of
the pump and the pump will then draw in air.
Long time of operation with water containing air may
damage the pump and cause insufficient cooling of
the motor.
L4
L5
19