11
Use and installation instruction manual
ENGLISH
It is recommended to protect the electric pump from dry running by means of a
device such as a float, a level sensor or a normally open pressure switch connected
to the suction line (if the latter is pressurised).
4.2 Single-phase versions
Power the electric pump by means of a cut-off device, in accordance with the
installation requirements. The direction of rotation of the electric pumps does not
require any checks.
The single-phase electric pumps are fitted with automatic reset thermal
protection integrated in the motor.
4.3 Three-phase versions
Power the electric pump via a cut-off device, in accordance with the installation
requirements. Three-phase appliances must be protected against short-circuits
and overloads by a class 10 protection device, in accordance with IEC 60947-4.
Set the rated current according to the value shown on the rating plate. Use a
manual reset device.
CAUTION: Check which configuration of the electrical connections
corresponds to the available mains voltage on the rating plate and on the
markings on the motor. If required, change the configuration by moving the
jumpers to the appropriate terminals. At the end of the operation, check that the
electrical connections are secure and stable.
The direction of rotation must be checked by observing the motor on the cooling
fan side. Do not remove the protection devices to check the direction of rotation.
While checking the direction of rotation, run the motor for as short a time as
possible. If the direction of rotation cannot be visually checked, it is possible to
check it indirectly by installing the pump in the system and running it at maximum
flow rate (valves completely open, free delivery), according to one of the two
following modes:
• During operation, measure the maximum power consumption with an
ammeter clamp. If the direction of rotation is incorrect, the values will be nearly
double those specified on the rating plate.
• Alternatively, run the machine for a few seconds, then reverse the direction of
rotation and repeat the operation. The correct direction is the one in which the
greatest flow rate is obtained.
To reverse the direction of rotation, it is sufficient to swap two phases between
them.
4.4 Variable frequency drive (VFD) applications
For variable frequency installations (power supply via “inverter”), make sure the
frequency inverter can supply the rated voltage and at least 10% more current
than the rated value shown on the rating plate. To install and connect the device,
please refer to the manufacturer's instruction manual.
5 HYDRAULIC CONNECTIONS
Before starting any work on the electric pump or the motor, make sure
that the power supply is disconnected, and it cannot be accidentally
restored.
Installing the electric pump can be complex and dangerous for people.
This operation must, therefore, be performed by competent, qualified
installers.
Comply with the current accident-prevention regulations, use suitable protective
equipment and refer to the standards, legislation and local and/or national codes
of the country of installation for the connection to water and electrical mains.
The following indications regarding the verification of the NPSH and the
maximum pressure must be complied with to ensure the pump operates correctly
and to prevent damage to people or things.
5.1 Checking the NPSH
Check the electric pump characteristic curves to evaluate the NPSH factor (fig.
A3) and thus prevent cavitation problems in case of a difference in height
between the pump and the level of the liquid to be drawn or for excessively high
temperature. The pump must not work in the event of cavitation as this damages
the internal parts.
The maximum height of the pump from the liquid level “H” (fig. A4-B) can be
calculated with the following formula:
H = pb x 10.2 – NPSH - Hf - Hv – Hs
pb:
Barometric pressure or pressure of the liquid on suction [bar] (absolute
pressure).
NPSH: Suction head at maximum flow rate capacity [m] (EH: fig. A3)
Hf:
Pressure drop in the suction pipe at maximum pump flow rate [m]
Hv:
Vapour pressure [m] depending on the temperature of the liquid [m]
(see fig. A4-A)
Hs:
Safety margin [m] (minimum 0.5)
If the calculated value is less than “0”, the pump must be positioned below the
liquid level.
Example
pb = 1 bar
Pump type: EM 9/4 - 50 Hz
Flow rate: 12 m
3
/h
NPSH: 2 m
Hf = 2.5 m
Liquid temperature: +50°C
Hv: 1.3 m
H = pb x 10.2 - NPSH - Hf - Hv - Hs [m].
H = 1 x 10.2 - 2 - 2.5 - 1.3 - 0.5 = 3.9 [m]
This means that the maximum height between the pump and the level of the liquid to be drawn is 3.9
meters.
5.2 Maximum pressure check
Operating pressure
The sum of the maximum pressure created by the pump (see the rating plate) and
the inlet pressure (Pin) must not exceed the nominal pressure indicated on the
rating plate (Pmax). Use the following formula for the calculation:
Hmax [m] / 10 + Pin [bar] < Pmax [bar]
Pressure on suction
The suction pressure must be limited according to the previous point, so as not
to exceed the nominal pressure. In addition, it is recommended not to exceed the
following limits: EM 3 - max 2.0 bar; EM 5 - max 4.0 bar.
5.3 Minimum operating flow rate
WARNING
: The pump must never run dry (no liquid inside). The pump
must never run with the delivery valve closed for more than 5 seconds.
Prolonged operation at a flow rate lower than the minimum one indicated on the
rating plate may cause excessive and harmful overheating of the pump.
5.4 Pipes and system
Comply with the current accident-prevention regulations, use suitable
protective equipment and refer to the standards, legislation and local
and/or national codes of the country of installation for the connection to
water and electrical mains.
• Follow fig. A9 in the appendix for the installation.
• The liquid enters the pump from the base. The outlet can be in line with the
inlet or in the upper part of the pump, depending on the model (fig. A7 and
A8). The direction of flow is identified by the arrow on the base. Make sure that
the pump is connected correctly to the pipes.
• The hydraulic pipes must be suitable to the work pressure and nature of the
liquid pumped. The pipes must be adequately supported (fig. A9, detail 1) and
must not weigh on the unit. Do not force the pipe’s positioning when fixing
with the pump. Flexible pipes or compensation joints (fig. A9-2) are required
to prevent the transmission of vibrations from the pump to the pipes and vice-
versa.
• Provide an inclination not less than 2% to prevent air pockets in the suction
pipe.
• The pipe diameter must not be smaller than the diameter of the suction outlet
and must be airtight. If the suction pipe is larger than the outlet, install an
eccentric reducer (fig. A9-6).
• If the pump is installed above the level of the liquid to be drawn, a non-return
valve must be installed at the bottom of the pipe (fig. A9-3).
• The end of the suction pipe must be sufficiently submerged to prevent air
from entering through the suction vortex (fig. A9-7) when the liquid is at the
minimum level.
• Shut-off valves of a size suitable for the pipes must be installed at the suction
(fig. A9-4) and delivery (fig. A9-8) pipes, to isolate the pump from the circuit
in case of inspection and maintenance.
• Install a check valve (fig. A9-5) on the delivery pipe to prevent backflow and
water hammers when the pump is switched off.
• The dimensions of the pump connections are shown in fig. A7 and A8. Use
sealing material on the threads (sealing tape, liquid sealant, paste, hemp,
other). Use flat gaskets or O-rings on the oval flanges.
• The versions with two delivery outlets are supplied with a cap, which is to be
applied to either one according to the desired configuration.
6 MECHANICAL INSTALLATION
Remove the pump from the packaging and check that it is intact. Also
check whether the rating plate details match the desired ones. In case of any
discrepancies, contact the supplier immediately, specifying the nature of the
defects.
6.1 Handling the appliance
Follow the accident-prevention regulations in force.
To lift the machine, use only suitable, properly marked devices in good working
condition. Do not exceed the load capacity of the least resistant device among all
those used (lifting lug, shackle, hook, carabiner, chain, rope, hoist or other). Only
use hooks with safety latch. Refer to fig. A1 in the appendix.
