Lowara NSC2 Manual De Instalación, Funcionamiento Y Mantenimiento página 18

en - Original instructions
• All piping is independently supported, piping
must not place a burden on the unit.
• Flexible pipes or unions are used, in order to
avoid transmission of pump vibrations to the
pipes and vice versa.
• Use wide bends, avoid using elbows which
cause excessive flow resistance.
• The suction piping is perfectly sealed and air-
tight.
• If the pump is used in an open circuit, then the di-
ameter of the suction pipe is suited to the instal-
lation conditions. The suction pipe must not be
smaller than the diameter of the suction port.
• If the suction piping must be larger than the suc-
tion side of the pump, then an eccentric pipe re-
ducer is installed.
• If the pump is placed above liquid level, a foot
valve is installed at the end of the suction piping.
• The foot valve is fully immersed into the liquid so
that air cannot enter through the suction vortex,
when the liquid is at the minimum level and the
pump is installed above the liquid source.
• Appropriately sized on-off valves are installed on
the suction piping and on the delivery piping
(downstream to the check valve) for regulation of
the pump capacity, for pump inspection, and for
maintenance.
• Appropriately sized on-off valve is installed on
the delivery piping (downstream to the check
valve) for regulation of the pump capacity, for
pump inspection, and for maintenance.
• In order to prevent back flow into the pump when
pump is turned off a check valve is installed on
the delivery piping.
WARNING:
Do not use the on-off valve on the dis-
charge side in the closed position in or-
der to throttle the pump for more than a
few seconds. If the pump must operate
with the discharge side closed for more
than a few seconds, a bypass circuit
must be installed to prevent overheating
of the liquid inside the pump.
For illustrations that show the piping requirements,
see Figure 10 (page 338) and
338).
4.2 Electrical requirements
• The local regulations in force overrule these
specified requirements.
• In the case of fire fighting systems (hydrants
and/or sprinklers), check the local regulations in
force.
Electrical connection checklist
Check that the following requirements are met:
• The electrical leads are protected from high tem-
perature, vibrations, and collisions.
• The power supply line is provided with:
– A short-circuit protection device
– A mains isolator switch with a contact gap of
at least 3 mm
The electrical control panel checklist
3
fuses aM (motor starting), or magneto-thermal switch with curve C and Icn ≥ 4,5 kA or other equivalent device.
4
Overload thermal relay with trip class 10A + fuses aM (motor starting) or motor protection magneto-thermal switch with
starting class 10A.
18
Figure 11 (page
NOTICE:
The control panel must match the ratings of the elec-
tric pump. Improper combinations could fail to guar-
antee the protection of the motor.
Check that the following requirements are met:
• The control panel must protect the motor against
overload and short-circuit.
• Install the correct overload protection (thermal re-
lay or motor protector).
Pump Type
Single phase standard
electric pump ≤ 2.2 kW
Three phase electric
4
pump
• The control panel must be equipped with a dry-
running protection system to which a pressure
switch, float switch, probes, or other suitable de-
vice is connected.
• The following devices are recommended for use
on the suction side of the pump:
– When the liquid is pumped from a water sys-
tem, use a pressure switch.
– When the liquid is pumped from a storage
tank or reservoir, use a float switch or probes.
• When thermal relays are used, relays that are
sensitive to phase failure are recommended.
The motor checklist
WARNING:
• Read the operating instructions in or-
der to ensure whether a protection
device is provided if another motor
other than the standard is used.
• If the motor is equipped with automat-
ic thermal protectors, be aware of the
risk of unexpected starts in connec-
tion to overload. Do not use such mo-
tors for fire-fighting applications.
NOTICE:
• Only use dynamically balanced motors with a
half-sized key in the shaft extension (IEC
60034-14) and with normal vibration rate (N).
• The mains voltage and frequency must agree
with the specifications on the data plate.
In general, motors can operate under the following
mains voltage tolerances:
Protection
– Built-in automatic
reset thermal-am-
perometric protec-
tion (motor protec-
tor)
– Short circuit protec-
tion (must be sup-
plied by the instal-
3
ler)
– Thermal protection
(must be supplied
by the installer)
– Short circuit protec-
tion (must be sup-
plied by the instal-
ler)