Xylem LSNIH - Manual (Page 12)

Installation, Operating and Maintenance Instruction Model LSN
LSN 100-english page 10 Revision 01
Article No 771076024 Issue 01/2010
5.2.1 Suction and discharge pipe
The pipes must be of a size and design that liquid
can flow freely into the pump and that the pump
functions without problems. Particular attention is
to be paid to ensuring that suction pipes are
airtight and that the NPSH values are observed.
Under suction lift condition lay the suction pipe in
the horizontal section towards the pump so that it
is slightly inclined upwards so that no air traps
occur. Under positive suction head condition
install the suction pipe work slightly declined
towards the pump. Do not install fittings or elbows
right before the suction nozzle.
If the suction supply is under vacuum and
entrained gas may be present in the liquid, it is
recommended that a vent line be considered
upstream of the pump suction with return to the
suction supply, above the max liquid level.
An additional flushed piping - discharge branch-
vent line - makes it easier to de-aerate the pump
before start-up (pic 3).
pic 3
When laying the pipes, make sure that the pump
is accessible for maintenance, installation and
disassembly.
Notice "Permitted Forces on Flanges" (chapter
3.5).
If expansion joints are used in the pipes, they
have to be supported in such a way that the pump
is not loaded unduely high because of the
pressure in the pipes.
Before connecting up to pump: remove protective
coverings from suction and discharge branches.
Before starting up, the pipe system, fittings and
equipment must be cleaned to remove weld
spatter, scale etc. Any pollutants are to be
completely removed from pump units that are
directly or indirectly connected to drinking water
systems before being installed and taken into use.
To protect the shaft sealing (especially mechanical
seals)
against foreign impurities, it is
recommended that a sieve, 800 micron, is
installed in the suction/intake pipe when the motor
is being started up.
If the pipe system is tested with the pump
installed, do not exceed the maximum permitted
casing pressure of the pump and/or shaft sealing
(see data sheet).
When emptying the pipe after the pressure test,
make sure that the pump is treated properly
(danger of rust and problems when starting up).
In the case of pumps with stuffing boxes, replace
packing after pressure test (packing may be over-
compressed and thus no longer suitable for use).
5.2.2 Additional connections
Any required sealing, flushing or cooling pipe
connections must be installed. Please consult the data
sheet to see which pipes, pressures and amounts are
necessary. The position and size of connections to the
pump are given in the appendix, "Connections".
These connections are essential for the
function!
It is recommended that a pipeline is installed to take
off any leakage from the shaft seal. For connection,
see appendix, "Connections".
5.3 Coupling
Make sure that nobody can start the motor
during work on the coupling.
According to Accident Prevention Regulations,
the pump unit may only be operated when the
coupling guard is mounted.
On operation in zone 1 and 2 a coupling with
valid Atex-certification must be used.
The Operating Instructions of the manufacturer
must be followed.
5.3.1 Alignment of coupling
The alignment of the coupling must be carried
out with the utmost care and attention, so that
the unit will operate without failure. If you do not
pay attention to this hint you will lose your
warranty!
After mounting onto the foundation and the
connection of the pipings the coupling must be
adjusted again, even, if the unit was delivered
completely mounted on the frame.
Before starting installation, carefully clean shaft
ends and coupling components.
Before adjusting the coupling unfasten screws
(901.12) between bearing bracket (330) and
casing foot (183) and only fasten again after the
adjustment. Repeat measurement after fastening
of screws (901.12).
The unit is properly aligned, when a ruler, which is
laid axially over both coupling halves, has the
same distance to the particular shaft everywhere
on the circumference. Further, both coupling
halves must have the same distance to one
another on every of the circumference. This must
be checked by means of a tracer, gauge or dial
gage; refer to pic. 4 and 5.
The permitted tolerances for your coupling is
shown in the operating instructions of the