Lowara SV-B Instalación Funcionamiento Y Mantenimiento página 16

en - Translation of the original instructions
• System pressure (in a closed system)
• Resistance of the pipes
• Own intrinsic flow resistance of the pump
• Height differences
The following equation is used to calculate the maximum height above the
liquid level which the pump can be installed:
(p *10.2 - Z) ≥ NPSH + H + H
b f v
p Barometric pressure in bar (in closed system is system pressure)
b
NPSH Value in meter of the pump intrinsic flow resistance
H Total losses in meters caused by passage of liquid in the suction
f
pipe of the pump
H Steam pressure in meters that correspond to the temperature of
v
the liquid T °C
0.5 Recommended safety margin (m)
Z Maximum height at which the pump can be installed (m)
For more information, see Figure 7.
(p *10.2 - Z) must always be a positive number.
b
For more information about the performance, see Figure 5.
NOTICE:
Do not exceed the pumps suction capacity as this could cause cavitation and
damage the pump.
If hot water is pumped (it is the case of this type of pumps where Hv values
are high) do guarantee an appreciably high pb value as this could cause cavi-
tation and damage the pump.
4.2.2 Piping requirements
Precautions
WARNING:
• Use pipes suited to the maximum working pressure of the
pump. Failure to do so can cause the system to rupture, with
the risk of injury.
• Make sure that all connections are performed by qualified in-
stallation technicians and in compliance with the regulations
in force.
NOTICE:
Observe all regulations issued by the municipal authorities if the pump is
connected to the municipal water system. If required by the authorities, in-
stall appropriate backflow-prevention device on the suction side.
Suction and discharge piping checklist
Check that the following requirements are met:
• 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 resist-
ance.
• The suction piping is perfectly sealed and airtight.
• If the pump is used in an open circuit, then the diameter of the suction
pipe is suited to the installation conditions. The suction pipe must not be
smaller than the diameter of the suction port.
• If the suction piping must be larger than the suction side of the pump,
then an eccentric pipe reducer 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.
• In order to prevent back flow into the pump when pump is turned off a
check valve is installed on the delivery piping.
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 operation class 10A + fuses aM (motor starting) or motor protection magneto-thermal switch with operation class 10A.
12
+ 0.5
WARNING:
Do not use the on-off valve on the discharge side in the closed
position in order to throttle the pump for more than a few sec-
onds. 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 water inside the pump.
For illustrations that show the piping requirements, see Figure 12.
4.3 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 temperature, vibrations, and
collisions.
• The power supply line is provided with:
• A short-circuit protection device
• A high-sensitivity differential switch (30 mA) [residual current device
RCD] to provide additional protection against electric shock
• A mains isolator switch with a contact gap of at least 3 mm
The electrical control panel checklist
NOTICE:
The control panel must match the ratings of the electric pump. Improper
combinations could fail to guarantee the protection of the motor.
Check that the following requirements are met:
• The control panel must protect the motor against overload and short-cir-
cuit.
• Install the correct overload protection (thermal relay or motor protector).
Pump Type
Single phase standard electric pump
≤ 1,5 kW
Three phase electric pump and oth-
4
er single phase pumps
• The control panel must be equipped with a dry-running protection sys-
tem 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 water is pumped from a water system, use a pressure switch.
• When the water 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 order to ensure whether a
protection device is provided if another motor other than the
standard is used.
• If the motor is equipped with automatic thermal protectors,
be aware of the risk of unexpected starts in connection to
overload. Do not use such motors for fire-fighting applica-
tions and sprinkler systems.
Protection
• Built-in automatic reset thermal-
amperometric protection (motor
protector)
• Short circuit protection (must be
3
supplied by the installer)
• Thermal protection (must be
supplied by the installer)
• Short circuit protection (must be
supplied by the installer)
e-SV - English