Shaft
or shaft sleeves worn or scored at the packing
Packing
improperly installed
Incorrect
type of packing for operating conditions
Shaft
running off center because of worn bearings or misalignment
Rotor
out of balance resulting in vibration
Gland
too tight resulting in no flow of liquid to lubricate
packing
Failure
to provide cooling liquid to water-cooled stuffing
boxes
Excessive
clearance at bottom of stuffing box between shaft
and casing , causing packing to be forced into pump
interior
Dirt
or grit in sealing liquid , leading to scoring of
shaft or shaft sleeve
Excessive
grease or oil in antifriction bearing housing or
lack of cooling , causing excessive bearing temperature
Excessive
thrust caused by a mechanical failure inside the
pump or by the failure of the hydraulics balancing
device , if any
Lack
of lubrication
Improper installation of antifriction
bearings (damage during assembly , incorrect assembly
of stacked bearings , use of unmatched bearings
as a pair etc ., )
Dirt
getting into bearings
Rusting
of bearings due to water getting into housing
Excessive
cooling of water-cooled bearing resulting in condensation
in the bearing housing of moisture from the atmosphere
