foras 5FES 50HZ, Use And Installation Instruction Manual, Page: 6 / 8

Translation of the original instructions
ENGLISH
5" CLOSE-COUPLED PUMPS
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.
In case of breakage, the electric pump can release up to 50 cl of oil. Occasional
ingestion of oil is not dangerous for human health. The risk of an oil leak should
be limited as much as possible. Plan it during installation.
Refer to fig. A1 (submerged installation) and fig. A2 (surface installation) in the
appendix.
5.1 Delivery piping
The pipe diameter determines the flow rate and pressure available at the points
of use. Small diameter pipes reduce performance and increase water hammers
and the risk of cavitation. Adopt flow cross-sections as great as the piping length
(possibly with a larger diameter than that of the port of the electric pump).
It is advisable to install a non-return valve (B in fig. A1 and fig. A2 ), to avoid
emptying the delivery pipe following the shutdown of the electric pump and to
avoid backflow. Firmly tighten the piping on the port, without damaging it. The
electric pump can be installed both with a metal pipe and one in other material.
If you intend to use the delivery pipe to support the pump (e.g. fig. A1 and fig.
A2 , left side), always check that it is sufficiently strong and rigid to withstand the
combined action of the starting torque, the liquid pressure, the vibrations and the
electric pump weight. Alternatively, in the case of submerged installations, it is
advisable to support the electric pump with a metal cable firmly secured to the
eyelet of the head and constrain the electric pump with respect to rotation. For
surface installations, the electric pump can be supported by securing it directly
with clamps (D in fig. A2 , right side).
5.2 Installation in the well
The maximum diameter of the electric pump is 129 mm. Check that the well has
no restrictions or obstacles hindering the descent of the electric pump. The gap
between the electric pump and the walls of the well must be adequate for the
required flow rate. An internal well diameter of at least 140 mm is recommended.
The motor is cooled by the water flow inside the electric pump. Therefore, a
minimum speed value is not required.
Secure the power cable to the delivery pipe using specific clamps ( fig. A1 ).
Do not underestimate the risk of falling and drowning if the installation is to be
carried out in a large well, in a tank or in a reservoir.
Make sure that there is no risk of toxic, suffocating fumes or harmful or potentially
explosive gases in the work atmosphere. Use appropriate PPE, if necessary.
It is recommended to check that the well is not obstructed along its entire length.
Lower the electric pump into the well to avoid damaging the electric cable.
Do not use the power cable to lower or support the electric pump in the well.
5.2.1 Minimum and maximum immersion
In order not to draw in air through the filter, the electric pump must be immersed
in the liquid up to at least half its height and in any case, not less than 30 cm from
the bottom (MIN level in fig. A1 ). Ensure sufficient immersion so as to guarantee
this condition when the liquid in the well reaches the minimum level. Dry running
or with air mixed with liquid can cause serious damage to the electric pump and
irregular performance.
The maximum immersion depth (MAX level in fig. A1 ) is shown on the rating plate.
5.2.2 Models with float
The models fitted with a float start automatically when the float exceeds
approximate angle of 45° with respect to the horizontal line. The motor stops
automatically when the float drops below the horizontal line again. During
installation, it is necessary to verify that:
1) The float is free to move in both directions without getting stuck or caught.
Remove any obstacles. Check all the space around the electric pump, in all
directions allowed.
2) The electric pump only starts when the liquid reaches a level that is at least
equal to the minimum prescribed immersion (see the previous section) and
stops before the liquid drops below this level. Adjust the free length of the float
cable to achieve the desired result.
5.3 Surface installation
Models with in-line ports are designed to be installed between two pipe sections.
Refer to fig. A2 in appendix.
Make sure that the misalignment between the two pipes does not generate an
excessive load on the electric pump connections. It is advisable to install a flexible
section on at least one of the two sides (E in fig. A2 ). Adequately support the
pipes so as to avoid transmitting excessive force or torque to the ports of the
electric pump.
We recommend installing shut-off valves on the outlet and, if the line is
pressurised, at the pump inlet, so as to perform maintenance without draining
the hydraulic system (C in fig. A2 ).
If the electric pump sucks from a non-pressurised line (e.g. a well or a tank, at a
higher height than that of the exposed surface) it is necessary to install a foot or
non-return valve along the suction pipe to prime the pump (B in fig. A2 ).
The pump does not have a filler cap. If the pump is installed with suction life, it is
advisable to install a fitting that allows air to be filled and vented.
5.3.1 Checking the maximum suction pressure and NPSH
It is necessary to check that the sum of the suction pressure (P in) and the
maximum pump pressure increase (H max, in bar) is lower than the maximum
pump pressure (P max, in bar). In any case, the maximum suction pressure must
not exceed the value on the rating plate.]
Also check that the NPSH available at the electric pump inlet is higher than the
value required by the pump and take an adequate safety margin into account
so as to avoid the risk of cavitation. To calculate the available NPSH, use the
following formula:
NPSH = pb x 10.2 - Hv – Hs
pb: Absolute pressure of the liquid being sucked, with a running pump [bar].
Hv: Vapour pressure [m] depending on the liquid temperature [m]
Hs: Safety margin [m] (minimum 0.5)
The required NPSH values are specified in the characteristic curves shown in the
appendix ( fig. A3 ). Look for the frequency (columns) and family (rows) reference
charts.
If the required NPSH value ( fig. A3 ) exceeds the available NPSH value calculated
with the above formula, the pump with negative suction head must be installed
at a depth, in metres, equal to the difference between the two values. In closed
circuits, install the water pump unit/expansion vessel at the pump inlet and
pressurise the circuit.
6 MECHANICAL INSTALLATION
6.1 Machine handling
To lift the machine, use only suitable, properly marked devices (e.g. CE marking)
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 triggers. Use adjustable lifting lugs or
check their maximum load capacity for non-axial loads.
Pay attention to suspended loads. Do not stand under them. Pay attention
to people, animals and objects in the work area. Use appropriate work
area marking tools and delimiters, where necessary. Do not operate the
pump or let it pass over people.
The appliance can be moved manually.
Check the mass indicated on the rating plate and/or on the packaging.
6.2 Fastening
Secure the unit so that it remains stable and cannot move during operation, using
the delivery pipe or by securing the pump body directly.
Models equipped with brackets must be fixed using these methods.
7 START-UP AND PROLONGED STOP
Before starting the electric pump, it is necessary to fill it and the suction pipe with
water (the whole circuit, if the plant is closed). If an electric pump with positive
suction head is installed, perform the following operations manually.
Otherwise, if a negative suction head system is installed or the suction line is
pressurised, it is sufficient to open the valves, vent the air and wait for filling. In
closed circuits, load the system from the highest point and vent air at the same
time. During the first few seconds of operation, the pump will expel further air. If
the circuit is closed, vent it with appropriate valves.
Pay attention to leaks. Use appropriate PPE to protect against mechanical
and chemical risks.
Slowly open the valves during venting, avoiding sudden manoeuvres; do
not direct the jet towards people, animals or electrical appliances.
After prolonged downtime, check the pump for proper priming before starting it,
and vent the pipes, if necessary.
If a long period of inactivity is foreseen and/or the machine needs to be emptied
of liquid, disconnect it from the pipes and tilt it to let the liquid out.