Piping Requirements; Electrical Requirements - Xylem Lowara e-MPV Manuel D'installation, D'exploitation Et De Maintenance

(pb*10.2 - Z) ≥ NPSH
+ Hf + Hv + 0.5
R
pb Barometric pressure in bar (in closed
system is system pressure)
NPSH Value in meter of the pump intrinsic
R
flow resistance
Hf Total losses in meters caused by
passage of liquid in the suction pipe
of the pump
Hv Steam pressure in meters that
correspond 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) (pb*10.2 - Z)
must always be a positive number.
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.
Failure 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 backflow-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 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
Figure 8.
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
discharge side in the closed position in
order 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 9.
4.2

Electrical requirements


The local regulations in force overrule these
specified requirements.

In the case of fire fighting systems (hydrants
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 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-circuit.

Install the correct overload protection
(thermal relay or motor protector).
en - Original instructions
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