Lowara NSC2 Manual De Instalación, Funcionamiento Y Mantenimiento página 17

technicians and in compliance with
the regulations in force.
• Before starting work on the unit,
make sure that the unit and the con-
trol panel are isolated from the power
supply and cannot be energized. This
applies to the control circuit as well.
Grounding (earthing)
Electrical Hazard:
• Always connect the external protec-
tion conductor to ground (earth) ter-
minal before making other electrical
connections.
• You must ground (earth) all electrical
equipment. This applies to the pump
equipment, the driver, and any moni-
toring equipment. Test the ground
(earth) lead to verify that it is connect-
ed correctly.
• If the motor cable is jerked loose by
mistake, the ground (earth) conductor
should be the last conductor to come
loose from its terminal. Make sure
that the ground (earth) conductor is
longer than the phase conductors.
This applies to both ends of the motor
cable.
• Add additional protection against le-
thal shock. Install a high-sensitivity
differential switch (30 mA) [residual
current device RCD].
4.1 Facility requirements
4.1.1 Pump location
DANGER:
Do not use this unit in environments that
may contain flammable/explosive or
chemically aggressive gases or powders.
Guidelines
Observe the following guidelines regarding the loca-
tion of the product:
• Make sure that no obstructions hinder the normal
flow of the cooling air that is delivered by the mo-
tor fan.
• Make sure that the installation area is protected
from any fluid leaks, or flooding.
• If possible, place the pump slightly higher than
the floor level.
• The ambient temperature must be between 0°C
(+32°F) and +40°C (+104°F).
• The relative humidity of the ambient air must be
less than 50% at +40°C (+104°F).
• Contact the Sales and Service Department if:
– The relative air humidity conditions exceed
the guidelines.
– The room temperature exceeds +40°C
(+104°F).
– The unit is located more than 1000 m
(3000 ft) above the sea level. The motor per-
formance may need to be de-rated or re-
placed with a more powerful motor.
For information about which value to de-rate the mo-
tor with, see Table 8 (page 337).
Pump positions and clearance
Provide adequate light and clearance around the
pump. Make sure that it is easily accessible for in-
stallation and maintenance operations.
Installation above liquid source (suction lift)
The theoretical maximum suction height of any
pump is 10.33m. In practice, the following affect the
suction capacity of the pump:
• Temperature of the liquid
• Elevation above the sea level (in an open sys-
tem)
• 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 maxi-
mum height above the liquid level which the pump
can be installed:
(p *10.2 - Z) ≥ NPSH + H
b
p Barometric pressure in bar (in closed sys-
b
tem is system pressure)
NPSH Value in meter of the pump intrinsic flow re-
sistance
H Total losses in meters caused by passage of
f
liquid in the suction pipe of the pump
H Steam pressure in meters that correspond
v
to the temperature of the liquid T °C
0.5 Recommended safety margin (m)
Z Maximum height at which the pump can be
installed (m)
(p *10.2 - Z) must always be a positive number.
b
For more information, see
NOTICE:
Do not exceed the pumps suction capacity as this
could cause cavitation and damage the pump.
4.1.2 Piping requirements
Precautions
WARNING:
• Use pipes suited to the maximum
working pressure of the pump. Fail-
ure to do so can cause the system to
rupture, with the risk of injury.
• Make sure that all connections are
performed by qualified installation
technicians and in compliance with
the regulations in force.
NOTICE:
Observe all regulations issued by authorities having
jurisdiction and by companies managing the public
water supplies if the pump is connected to a public
water system. If required, install appropriate back-
flow-prevention device on the suction side.
Piping checklist
Check that the following requirements are met:
en - Original instructions
+ H + 0.5
f v
Figure 9 (page 337).
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