Symptom
Cause
Remedy
Suction pressure too high
Check liquid levels and static suction
pressure
Bearing installed incorrectly
Check bearing orientation to sectional
drawing
Impeller out of balance
Check pump vibrations, if necessary
rebalance impeller
Overheating of seal faces
Check flush flow with mfgr’s recom-
mendation, increase if necessary
Excessive shaft deflection
Check shaft diameter, sag and deflec-
tion, consult factory
Lack of seal flush to seal faces
Check shaft diameter, sag and deflec-
tion, consult factory
Incorrect seal installation
Check seal materials vs. pumpage to
determine compatibility
Pump is run dry
Fill system piping completely so the
impeller is submerged
Pump run off design point
Check head and flow, AF’s should
normally be run between 75% and
125% of BEP
Shaft/shaft sleeve worn
Replace shaft or shaft sleeve if nec-
essary
Coupling out of balance
Check pump and drive component vi-
bration levels, rebalance coupling if
necessary
Sub-base not installed correctly
Compare pump sub-base installation
to instruction manual
Bearing failing
Replace if necessary
Piping not properly anchored
Check to see if excessive pipe strain
is being transferred to pump flanges
Pump and/or driver not secured to
sub-base
Check fasteners, if loose check align-
ment and re-tighten
Specific gravity higher than specified Analyze pumpage and compare to
specified gravity
Viscosity higher than specified
Analyze pumpage and compare to
specified viscosity
Pump assembled incorrectly
Compare pump assembly to instruc-
tion manual
Motor requires excessive power
Head higher than rating. Reduced
flow
Check for fouling in the piping or ob-
struction in discharge
Liquid heavier than expected
Check specific gravity and viscosity
Incorrect rotation
Jog motor and check rotation
Pump run off design point
Check measured head and flow to
specified head and flow
Stuffing box packing too tight
Readjust packing. Replace if worn
Rotating parts binding, internal clear-
ances too tight
Check internal wearing parts for prop-
er clearances
7.1 Pump Troubleshooting
64
Model AF (42"/1200mm/54"/60"/66") LM/LMR Bearings Installation, Operation, and Maintenance Manual