Installation and operating instructions WILO Mather and Platt – VT pumps 34
10.4.3 Normal starting and running checks
• When all the foregoing prestart checks are satisfactory, Start
the pump and check the direction of rotation (indicated by a
direction arrow on the motor stool) otherwise stop the pump
immediately for correction of direction of rotation. Then run
the pump at its rated speed.
• Check the ammeter reading to ensure that the motor is not
being overloaded.
• If applicable, ensure that the stuffing box is not overheating
and that there is slight leakage from the gland (about 1 drop
per second). There may be at first a tendency for the stuffing
boxes to run warm because of the high viscosity lubricant in
the packing. During the first few minutes of running with new
packing, a small quantity of very viscous fluid will be
extruded, but the flow should reduce when the packing has
settled down.
• Check that the bearing is not overheating. Bearings will
normally run at a temperature of 30 ˚C to 35 ˚C above
ambient temperature. The ideal running temperature of
bearings is 40 ˚C to 60 ˚C for ball bearings and 40 ˚C to 55 ˚C
for spherical roller bearings. The temperature should never
exceed 85 ˚C for bearings. If the bearings are overheating its
cause should be investigated immediately.
• If the foregoing checks are satisfactory, open the delivery
valve slowly and bring the pump gradually up to its rated
parameters indicated in the data sheet/name plate and based
on pressure gauge and ammeter readings. Unless the pump is
fitted with a special leak off device, it should not be run for a
long period against a closed delivery valve. Check that the
driving unit is not being overloaded during valve opening.
Overloading may occur if the pump is discharging into an
empty system. If the pumping unit fails to generate at least
its rated delivery pressure it must be stopped immediately,
the cause ascertained,
• Check vibration of pump set and ensure that vibration level is
within limits specified as per HIS standard (see page no. 38 for
reference)
• The pumps may be run for 8 hours trial operation and all the
parameters like delivery pressure, current, bearing
temperature, etc. Be recorded periodically. Make the
following checks at regular intervals. It is recommended that
they be made at every change of shift.
• Check the suction and discharge pressure gauge for normal
operating pressure, if there is significant drop in the suction
or discharge pressure the pump may have lost its supply. In
the event of this fault occurring, the pump must be stopped
immediately, and the cause of liquid loss eliminated.
• Check the mechanical seal or stuffing box assembly for
overheating.
10.4.4 Sealing system
Gland packing
CAUTION! Risk of damaging the pump!
If the gland plate is too tight, the packing stuff will be
immediately
dam
a
ge.
At the beginning of the operation, the leak at the gland
packing should be important. It should reduce
progressively after several hours by a balanced and
reasonable tightening the gland plate. The gland packing
must operate without excessive temperature. The correct
setting of the gland packing let a permanent leak around
40 to 60 drops per minute.
If this leak is too much and cannot be adjusted with the
gland plate, the packing stuff are worn and must be
replaced.
Mechanical
seal
CAUTION! Risk of damaging the pump!
A mechanical seal must never operate without fluid and
lubrication even for a short period of time.
Ensure that the pump is completely full of water and
vented before starting the pump. Small leakages can
occur during the period of running-in, they should
disappear after several hours of operation. If the leakages
don’t stop, shut down the pump disassemble the
mechanical seal and control their condition.
10.4.5 Normal shutdown
WARNING! Risk of Burns!
If the fluid temperature and system pressure is high,
close the isolation valves upstream (in case of barrel
pumps) and downstream of the pump. Initially let the
pump cool.
• Stop the driver of the pump.
• When the pump has come to rest, close the delivery valve.
• Isolate any ancillary supplies.
10.4.6 Emergency Shutdown
In the event of any malfunction of the equipment, switch
off the pump set. When the pump has come to rest, close
the discharge valves, isolate the driving unit power supply
& rectify the fault.
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