Filling And Venting; Starting The Pump - Wilo SCP Série Notice De Montage Et De Mise En Service

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8.1.2 Cleaning of bearings
SCP pumps are fitted with pre-lubricated, sealed
bearings which do not require external lubrication
for life. For Ball bearings which require external
greasing and if the unit has been in store for a long
period before commissioning, the bearings should
be cleaned and flushed out with clean white spirit
or good quality paraffin. Waste oil/paraffin & used
cotton cloth should not be used for this purpose,
as particles of foreign matter may be left behind
which would cause damage when the bearing is in
service. Bearings should be then filled with recom-
mended grade and quality of fresh lubricant to the
level. Refer list of lubricants at the end of this
manual.

8.2 Filling and venting

Fill and vent the system correctly, through air
cock. Brief dry running will damage the pump.
Please also note that these pumps are not self-
priming, which means that the impeller & casing
must always be fully filled with fluid to be handled
before putting in operation
WARNING! Danger of injury!
There is a risk of burns if the pump is touched!
The entire pump may become very hot, depen-
ding on the operating state of the pump or sys-
tem (fluid temperature).
CAUTION! Danger sealing system damage!
Any attempt to run the pump dry or partially full
may result in seizure of the rotating internal
components.
8.2.1 Pumps operating on flooded suction head
When these pumps operate on a flooded open the
air release valve situated on top of the pump
casing, open the pump inlet isolating valve and
vent the air out of the casing. When the liquid
issues from the air vent, free of air, the pump is
properly primed. The air vent must be closed after
priming and before the pumping set is started..
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8.2.2 Pumps operating on negative suction head
There are two methods of priming pumps that
draw their liquid from an elevation lower than the
pump inlet branch:
• If the inlet pipe work is fitted with a non-return
foot valve, the pump casing and inlet pipe work
can be filled with liquid from an external source
under pressure. The pressure imposed on the
pump by this method must not exceed that for
which the pump is designed. In certain cases pri-
ming can be achieved by flooding back from the
delivery side of the pump.
• By extracting air or gas from the pump casing. To
enable this method to be used, the gland arrange-
ment must be sufficiently air-tight or it should be
liquid sealed from an external supply. For opera-
tion details of gas exhausts reference should be
made to the manufacturer's instructions. Some
form of priming indicator is usually fitted to indi-
cate when the priming operation is complete.
8.2.3 Pumps operating on hot liquids
Pumps operating on hot liquids are usually so
arranged that the liquid flow into the pump is
under pressure. If the saturation pressure of such
liquids is above atmospheric pressure, any
attempt to prime the pump will result in the liquid
"flashing" from the air cocks. For these reasons,
the air cocks at the top of the pump casing should
be left slightly open when priming boiler circula-
ting pumps until air has been driven out of the
casing completely.
The cooling water services of a pump handling hot
liquids should be turned on before the pump is pri-
med. These services may supply cooling water to
the bearings and / or stuffing boxes. Where the
services are functioning, open the inlet valves and
start warming the pump throughout. Never cut off
the water services while the pump is "on tempera-
ture". Where bearings are water-cooled, adjust
the cooling water supply until the bearings have a
running heat. Over-cooling may lead to conden-
sation of moisture from the atmosphere inside the
bearing with consequent contamination of the oil.
The suction valve, if provided, must be fully open
and the delivery valve must be closed.

8.3 Starting the pump

8.3.1 Direction of rotation
Disconnect the drive coupling and run the motor
to check its direction of rotation. A directional
arrow is provided on the pump unit.
WILO SE 10/2019