Installation and operating instructions Wilo
–
SCPV pumps
17
7.2.6 Discharge line (Refer Figure: 6&7)
CAUTIO N! Damage to the pump
Pump casings have sometimes been cracked by
pressure surges imposed on them through the
absence of a non-return valve. A back flow can
seriously damage the bearings and the
mechanical seal.
A suitable valve should be fitted in the delivery
pipe as near to the pump as possible. Unless the
pump is to deal with only small quantities of liquid
at a low delivery head, or where back surge is likely
to occur, a non-return valve must be fitted in the
delivery line as close to the pump delivery branch
as possible. A by-pass valve fitted to non-return
valves is often an advantage, although this is not
always required. Pressure gauges should be fitted
to the tapings provided in the pump suction and
discharge branches. These will give useful
indication of the pump behavior.
7.2.7 Stuffing box packing (Refer Figure: 8)
CAUTION! Risk of quick wear or leakages packing
should be handled with care and it should not be
allowed to pick up the dust or abrasive matter by
coming into contact with floors or dirty benches. It
is bad practice to hammer packing to facilitate the
insertion.
Pumps are dispatched from our works with the
stuffing boxes unpacked; otherwise packing will
be aged. The packing is packed with greaseproof
paper and dispatched with the pump. The softest
possible packing i.e. plaited cotton impregnated
with oil and colloidal graphite is recommended for
most duties. Required number of and lengths of
packing should be cut off so that each length will
pass once round the shaft sleeve line and meet to
end. The ends of packing must be cut at 45 °. After
cleaning the stuffing box and shaft sleeves the
packing should be inserted into the stuffing box.
Each ring should be pushed into position
individually using the glands joint of each ring
must be positioned 180
˚
from joints of its
neighbor. A logging ring included in the
arrangement; should be inserted into the stuffing
box at the appropriate time during the packing
sequence so that it is aligned with the cooling
water connection. The gland should now be fitted
square with the pump casing and the nut should
be screwed up to little more than finger
tightness.
7.2.8 Pressure gauge connections
CAUTION! Risk of leakage of the fluid!
Never connect a pressure gauge onto the
pump when the system is under pressure.
Pressure gauge connections are available on the
pump casing close to the flanges. Then pressure
gauge can be connected on suction and discharge
side
7.2.9 Mechanical seal
CAUTIO N! Damage to the pump
Never start the pump without liquid inside
otherwise the mechanical seal will be damaged
instantaneously.
No real operation is required during the setup of
the pump. Only filling and venting the pump are
mandatory before switching on the main.
7.2.10 Electrical connection
WARNING! Danger of electric shock
The electrical connection should be established
by an electrician approved by the local electricity
supply company in compliance with the
applicable local regulations [e.g. VDE regulations].
The current type and voltage of the mains
connection must correspond to the specifications
on the name plate.
Refer to the motor and panels instruction manual at
the time of installation and connection. Motors or
electrical control panels are operated with
alternating or industrial high-voltage current.
The electrical connection is established via a fixed
mains connection line.
The local regulations must be adhered to.
Ensure that there is a provision for isolation of all
energy sources and locking. If the machine has been
switched off by, a protective device, it must not be
switched on again until the error has been
corrected.
The electrical system (machine including protective
devices and operating position) must always be
grounded. Refer pump GA drawing & respective
manuals of motor/electrical control panel for
connecting earthing suitable as per motor rating
and relevant regulations and standards including
proper earthing lug size and fasteners.
Under no circumstances may any connecting cables
touch the pipeline or the pump or motor housing.
If there is a possibility that people can come into
contact with the machine and the pumped liquid
(e.g. at construction sites), the grounded
connection must be additionally equipped with a
fault current protection device.
To ensure drip water protection and strain relief of
the cable connections, use cables with an
appropriate outer diameter and screw the cable
glands tight. Furthermore any cables nearby
screwed connections for outlet loops should be
bent in order to divert any accumulating drip water.
Close any unassigned cable glands with the existing
sealing discs and screw them tight.
7.2.11 Operation with frequency converter
The rotation speed can be adjusted in the opera ting
limits of the pump given in the technical data. The
electrical motors can be driven by a frequency converter in
order to adapt the pump performances the duty point
required. Please contact Wilo before connecting the
frequency converter to the motor to make sure that the
electrical motor is compatible with this driver. In any case,
please inform Wilo at the quotation stage if the pump set
will by driven by a frequency converter this might
influence the motor selection.
