6.6.2. Delivery pipe
Install a gate valve in the delivery pipe to regulate flow-
rate, head and absorbed power.
Install a pressure gauge between the pump and the
gate valve.
GB
ATTENTION: install a check valve between the pump
and the gate valve in order to avoid reverse flow after
switching off the pump unit and to protect the pump
from water hammering.
With servo-operated shut-off devices, provide an air
vessel or other protection device against surge of
pressure in the case of sudden changes of flow rate.
6.7. Electrical connection
OFF
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
Compare the frequency and mains voltage with the
name-plate data and connect the supply conductors
to the terminals in accordance with the appropriate
diagram inside the terminal box cover.
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.
ATTENTION: with motor power rating ≥ 5.5 kW
avoid direct starting. Provide a control panel
with star-delta starting or an
device.
If the terminal box is provided with an inlet gland, use
a flexible power supply cord of the H07 RN-Ftype with
section of cable not less than (par. 16 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 residual
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 protection
device with curve D appropriate for the rated current
of the pump.
Single-phase MXV-BM, are supplied with a capacitor
connected to the terminals and (for 220-240 V - 50 Hz)
with an incorporated thermal protector.
Electrical diagram (only for Calpeda motors)
W2 U2
V2
W2 U2
U1 V1 W1
U1 V1 W1
L3 L2 L1
L3 L2 L1
MXV-B 25,32,40
MXV(L), MXV(L)4 25,32,40,50 MXV(L), MXV(L)4 65-80
Page 18 / 136
marking.
other starting
V2
W2 U2
V2
W2 U2
U1 V1 W1
L1 L2 L3
L1 L2 L3
MXV-B 50
Refer to any other instructions (if supplied) for use
of the motor.
ATTENTION: When the pump is fed by a
frequency converter, the minimum frequency
should not fall below 25Hz and in any case the
total head of the pump should never be lower
than 3 m.
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.
Make sure the coupling with the pump shaft turns
freely when rotated by hand (see section 6.5.).
Make sure the screws (64.25) of the coupling are
tightened (see section 9.2.).
Make sure the coupling guard (32.30) is
fastened on the lantern bracket.
For MXV-B Make sure the shaft turns freely when
rotated by hand.
For this purpose use the screwdriver notch on the shaft
end ventilation side.
7.2. First starting
OFF
ATTENTION: never run the pump dry, not even for a
short trial run.
Start the pump after filling it completely with liquid.
When the pump is located above the water level
(suction lift operation, fig. 3A) or with a positive suction
head which is too low (less than 1 m) to open the non-
return valve, fill the suction pipe and the pump through
the priming hole (1) (fig. 4).
To facilitate this operation use a flexible tube (or elbow)
and a funnel.
MXV-B, MXV(L) 25-32-48, MXV(L)4 25-32-48
During filling, the needle screw (14.17) in the drainage
plug (14.12) must be kept loose so as to allow a free
passage between the pressure chamber and the
suction chamber (Fig.4a).
In case of horizontal installation (only for MXV 50),
arrange the screw (14.17) upwards. The screw is both
used for filling and as air vent.
MXV-B, MXV 25-32-40-50
Filling and
air vent 14.04
V2
U1 V1 W1
Fig. 4a Filling:
internal passage open
MXV, MXV-B Rev6 - Operating Instructions
Fig. 4c Drainage
14.12
(1)
4.93.306
Fig. 4b Operating:
internal passage closed
4.93.008
14.17