Lowara NSC Serie Manual De Instalación, Funcionamiento Y Mantenimiento página 19

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 11 on page 392.
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 + 0.5
f v
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:
• 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
en - Original instructions
Figure 12 on page 392.
19