b) If the pump exceeds normal levels, then shut down the pump immediately and correct the prob-
lem.
7.
Repeat steps 5 and 6 until the pump runs properly.
5.7 Pump operation precautions
General considerations
NOTICE:
•
Vary the capacity with the regulating valve in the discharge line. Never throttle the flow
from the suction side. This action can result in decreased performance, unexpected heat
generation, and equipment damage.
•
Risk of equipment damage from unexpected heat generation. Do not overload the driver.
Ensure that the pump operating conditions are suitable for the driver. The driver can over-
load in these circumstances:
•
The specific gravity or viscosity of the fluid is greater than expected
•
The pumped fluid exceeds the rated flow rate.
Operation at reduced capacity
WARNING:
•
Risk of breach of containment and equipment damage. Excessive vibration levels can
cause damage to bearings, stuffing box, seal chamber, and/or mechanical seal. Observe
pump for vibration levels, bearing temperature, and excessive noise. If normal levels are
exceeded, shut down and resolve.
•
Risk of explosion and serious physical injury. Do not operate pump with blocked system
piping or with suction or discharge valves closed. This can result in rapid heating and va-
porization of pumpage.
•
Risk of equipment damage and serious physical injury. Heat build-up can cause rotating
parts to score or seize. Observe pump for excessive heat build-up. If normal levels are
exceeded, shut down and resolve.
NOTICE:
Cavitation can cause damage to the internal surfaces of the pump. Ensure net positive suction
head available (NPSH
A
) always exceeds NPSH required (NPSH
3
) as shown on the published
performance curve of the pump.
Operation under freezing conditions
NOTICE:
Do not expose an idle pump to freezing conditions. Drain all liquid that will freeze that is inside
the pump and any auxiliary equipment. Failure to do so can cause liquid to freeze and damage
the pump. Note that different liquids freeze at different temperatures. Some pump designs do
not drain completely and may require flushing with a liquid that doesn't freeze.
5.7 Pump operation precautions
44
Model 3355 Installation, Operation, and Maintenance Manual
