Xylem AC5660 Series A-C 1500 Vertical In-Line Pump - Manual (Page 19)

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.
NOTICE:
• 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 flush lines. 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.
Note on the packed pump operation
Tighten the gland nuts
Before you start the pump, back off the packing gland nuts or screws until the gland is
loose.
Hand tighten until the gland is snug against the first packing ring. Initially, water might
freely run from the packing. This is normal and should be allowed to continue for a period
of time before you continue to tighten the gland. Tighten the gland nuts slowly and one
flat at a time.
Commissioning, Startup, Operation, and Shutdown
Series A-C 1500 Installation, Operation, and Maintenance Manual 17