Grundfos MULTILIFT M Installation And Operating Instructions Manual page 7

2.1.1 Pump
The pump impellers are designed as free-flow vortex
impellers ensuring almost unchanged performance
throughout the entire life of the pump. The stator
housing of the motor is made of cast iron with a 150
µm epoxy coating. The pump has a mechanical shaft
seal.
Single-phase motors are protected by a thermal
switch in the windings. MULTILIFT M, MD and MLD
run via a capacitor inside the controller cabinet.
MULTILIFT MOG and MDG run via starting and
operating capacitors inside the controller cabinet.
Three-phase motors are protected by a thermal
switch in the windings and an additional thermal
circuit breaker in the controller cabinet to cut out the
motor in case of overload.
If the phase sequence for three-phase pumps is
wrong, the controller indicates fault and prevents the
pump(s) from starting.
MULTILIFT MOG, MDG: The pump has a grinder
which grinds solid particles into small pieces so that
they can easily flow through pipes of a small
diameter.
MULTILIFT M, MD, MLD: If the
motor is overloaded, it stops
automatically. When it has cooled to
normal temperature, it restarts
automatically.
MULTILIFT MDG lifting stations have two
pumps, thus providing a standby pump in
case of pump failure or additional pump
performance if the inlet exceeds the
performance of one pump.
Always install MULTILIFT MDG lifting
stations if the wastewater flow must not be
interrupted.
Performance curves are available in the data booklet,
which you can download via the QR code or link
below:
http://net.grundfos.com/qr/i/98288126
2.1.2 Level sensor
The piezoresistive pressure sensor placed in the
controller is connected via a hose to a pressure tube
in the tank. The screw cap where the hose is
connected includes a connection for a DN 100 tube.
This tube, the pressure tube, extends down into the
tank. The rising liquid level compresses the air inside
the pressure tube and hose, and the piezoresistive
sensor transforms the changing pressure into an
analog signal. The control box uses the analog signal
to start and stop the pump and to indicate high-level
alarm. The pressure tube is fixed underneath the
screw cap and can be taken out for maintenance,
service and cleaning the inside of the tube. An O-ring
ensures tightness.
MULTILIFT M, MD, MLD: The hose is supplied in
lengths of 4 or 10 m.
MULTILIFT MOG, MDG: The hose is supplied in a
length of 10 m.
The hose must be connected to the controller.
Screw cap with hose and DN 100 tube
7