Bell & Gossett P81567F Series 1531 - Manual (Page 20)

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.
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.
Leakage rate
An adequate leakage rate is not one single value for all pumps and installations, but is the
amount required to provide adequate cooling and lubrication. The required leakage is
influenced by operating pressure, fluid temperature, shaft speed, and so forth. For fluid
temperatures in the range of 32°F to 190°F (0°C to 88°C), average leakage rates of 60 to
80 drops per minute are recommended. However, each individual pump and installation
has unique operating conditions that result in widely-variable leakage rate requirements.
Commissioning, Startup, Operation, and Shutdown
18 Series 1531 Installation, Operation, and Maintenance Manual