Commissioning; Cleaning Prior To Start; Filling And Venting; Starting The Pump - Wilo MISO 25-125 Manual

8 Commissioning

WARNING! Danger of injury
The devices whether on pump/motor/electrical panels
must never be dismantled or disabled. They must be
checked by an authorized technician for proper
functioning before, start-up. Refer to motor &
electrical panel instruction manuals for electrical
safety & control devices information.
WARNING! Danger of pump damage!
Do not operate the pump away from specified
operating range. Operating beyond duty point may not
pose a risk to the operator but will reduce the
efficiency of the pump or damage the pump itself.
Operation more than 5 minutes, at close valve
condition is not recommended. For hot liquids this is
not recommended at all. Ensure that always site
NPSH-A is more than NPSH-R.

8.1 Cleaning prior to start

8.1.1 Pipe work flushing
Before the pumps are brought into service, either on
initial commissioning or on re-commissioning after
overhaul, the pipe work associated with the pumps must
be flushed through. This will clear deposits or scales
which may have accumulated in the pipes, and which
could damage the internal components of the pumps.

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, depending on the
operating state of the pump or system (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.
Installation and operating instructions WILO Mather and Platt –MISO / PISO Pumps
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.
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 priming 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 arrangement must be
sufficiently air-tight or it should be liquid sealed from an
external supply. For operation details of gas exhausts
reference should be made to the manufacturer's
instructions. Some form of priming indicator is usually fitted
to indicate 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 circulating 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 primed. 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
temperature". Where bearings are water-cooled, adjust the
cooling water supply until the bearings have a running heat.
Over-cooling may lead to condensation 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.
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