than 1.5 m/s for suction and 3 m/s for delivery.
The pipe diameters must never be smaller than the
pump connection ports.
6.4.2. Suction pipe
The suction pipe must be perfectly airtight and be led
upwards in order to avoid air pockets.
Use an eccentric transition piece to join the suction
connection with a horizontal pipe of larger diameter
(fig. 2).
With a
pump located above the water level
(suc-
tion lift operation), fit a
foot valve with strainer
which must always remain immersed or a
check
valve
on the suction connection.
With
a pump located below water level
(inflow
under positive suction head) install a gate valve.
6.4.3. Delivery pipe
Fit a gate valve in the delivery pipe to adjust delivery,
head, and absorbed power.
Install a pressure gauge.
With a geodetic head of over 15 m fit a check valve
between the pump and the gate valve in order to pro-
tect the pump from water hammering.
6.4.4 Alignment of pump-motor unit (pumps NMS-
NMS4)
ATTENTION: for NMS and NMS4 pumps a misalign-
ment between pump feet and motor feet could cause
vibration and early wear of elastic bearings, the seal
and other internal parts.
Make sure the rotor turns freely when moved by
hand. For adjustment, loosen or tighten the screws
where necessary in order to move the position of the
support feet on the baseplate and to add calibrated
plates between the feet and baseplate wherever
these may be required.
6.5 Electrical connection
Electrical connection must be carried out only
by a qualified electrician in accordance with
local regulations.
Follow all safety standards.
The unit must be properly earthed (grounded).
Connect the earthing (grounding) conductor to the
terminal with the
marking.
Compare the frequency and mains voltage with
the name-plate data and connect the supply con-
ductors to the terminals in accordance with the
appropriate diagram inside the terminal box cover.
ATTENTION: with motor power rating ≥ 5.5 kW avoid
direct starting. Provide a control panel with star-
delta starting or an other starting device.
ATTENTION: never allow washers or other
metal parts to fall into the internal cable
opening between the terminal box and stator.
If this occurs, dismantle the motor to recover the
object which has fallen inside.
If the terminal box is provided with an inlet gland, use a
flexible power supply cord of the H07 RN-F type with
section of cable not less than (par. 13.3 TAB 1).
If the terminal box is provided with an inlet bushing,
connect the power supply cord through a conduit.
For use in swimming pools (not when persons are in
the pool), garden ponds and similar places, a
resi-
dual current device
with IΔN not exceeding 30 mA
must be installed in the supply circuit.
Install a
device for disconnection from the mains
(switch) with a contact separation of at least 3 mm in
all poles.
With a three-phase motor install an overload protec-
tion device with curve D appropriate for the rated cur-
rent of the pump.
Single-phase NMM,
are supplied with a capacitor
connected to the terminals and (for 220-240 V - 50
Hz) with an incorporated thermal protector.
6.6 Operation with frequency converter
Adjust the frequency converter so that the limiting
values of min. 25 Hz and max. f
N
Hz will not be
exceeded.
7 STARTUP AND OPERATION
7.1 Preliminary checks before start-up of the
pump
Do not start-up the device in case of damaged parts.
7.2 First starting
ATTENTION: never run the pump dry.
Start the pump
after filling it completely with liquid.
When the pump is located above the water level
(suction lift operation) fill the suction pipe and the
pump through the priming hole
Fig. 3
.
OFF
OFF
NM 40/20 - Operating Instructions
Page
5
c
b
a
d
4.93.040
Avoid formation of air pockets in suction pipe:
a) eccentric transition piece;
b) gate valve with horizontal handwheel;
c) pipe leading upwards.
Avoid trasmission of stress to the pump:
d) supports and anchoring of pipes.
Fig. 2 Connection of pipes.
4.93.141
Fig. 3 Filling.
IST NM 07_2018ed26_MXS 11_03con gall 19/06/18 09:03 Pagina 12
