Xylem P81547D Series 90 In-Line Centrifugal Pump - Manual (Page 18)

a) Check the pump for bearing temperature, excessive vibration, and noise.
b) If the pump exceeds normal levels, then shut down the pump immediately and
correct the problem.
7. Repeat steps 5 and 6 until the pump runs properly.
Pump operation precautions
General considerations
CAUTION:
• Vary the capacity with the regulating valve in the discharge line. Never throttle the flow
from the suction side since this can result in decreased performance, unexpected heat
generation, and equipment damage.
• Do not overload the driver. Driver overload can result in unexpected heat generation
and equipment damage. The driver can overload in these circumstances:
• The specific gravity of the pumped fluid is greater than expected.
• The pumped fluid exceeds the rated flow rate.
• Make sure to operate the pump at or near the rated conditions. Failure to do so can
result in pump damage from cavitation or recirculation.
Operation at reduced capacity
WARNING:
Never operate any pumping system with a blocked suction and discharge. Operation,
even for a brief period under these conditions, can cause confined pumped fluid to
overheat, which results in a violent explosion. You must take all necessary measures to
avoid this condition.
CAUTION:
• Avoid excessive vibration levels. Excessive vibration levels can damage the bearings,
stuffing box or seal chamber, and the mechanical seal, which can result in decreased
performance.
• Avoid increased radial load. Failure to do so can cause stress on the shaft and bearings.
• Avoid heat build-up. Failure to do so can cause rotating parts to score or seize.
• Avoid cavitation. Failure to do so can cause damage to the internal surfaces of the pump.
Operation under freezing conditions
NOTICE:
Do not expose an idle pump to freezing conditions. Drain all liquid that is inside the pump
and the cooling coils. Failure to do so can cause liquid to freeze and damage the pump.
Shut down the pump
1. Slowly close the discharge valve.
2. Shut down and lock the driver to prevent accidental rotation.
Commissioning, Startup, Operation, and Shutdown
Series 90 Installation, Operation, and Maintenance Manual 17