PB3 User Instruction
Page 36 of 39
6 FAULTS; CAUSES AND REMEDIES
Pump overheats and seizes
Bearings have short life
Pump vibrates or is noisy
Mechanical seal has short life
Mechanical seal leaks excessively
Pump requires excessive power
Pump loses prime after starting
Insufficient pressure developed
Insufficient capacity delivered
Pump does not deliver liquid
Cause
Remedy
A. SYSTEM TROUBLES
x
x
Pump not primed
Check complete filling. Vent and/or prime
x
x
x
x
Pump or suction pipe not
completely filled with liquid
x
x
x
x
Suction lift too high or level too
low
Check NPSH
a
>NPSH
r
, proper submergence, losses at
strainers and fittings
x
x
x
x
Insufficient
margin
between
suction pressure and vapor
pressure
x
x
x
Excessive amount of air or gas
in liquid
Check and purge pipes and system
x
x
x
Air or vapor pocket in suction
line
Check suction line design for vapor pockets
x
x
Air leaks into suction line
Check suction pipe is airtight
x
x
Air leaks into pump through
mechanical seal, sleeve joints,
casing joint or pipe plugs
Check and replace faulty parts
CONSULT PUMPIRAN
x
x
x
x
Inlet
of
suction
pipe
insufficiently submerged
Check out system design
x
x
x
Speed too low
CONSULT PUMPIRAN
x
Speed too high
CONSULT PUMPIRAN
x
x
x
Total head of system higher than
differential head of pump
Check system losses
Remedy or CONSULT PUMPIRAN
x
Total head of system lower than
pump design head
x
Specific
gravity
of
liquid
different from design
Check and CONSULT PUMPIRAN
x
x
x
Viscosity of liquid differs from
that for which designed
x
x
Operation at very low capacity
Measure value and check minimum permitted
Remedy or CONSULT PUMPIRAN
x
x
x
Operation at high capacity
Measure value and check maximum permitted.
Remedy or CONSULT PUMPIRAN
x
x
x
Suction
pressure
too
low
Foreign material in suction line
Open suction valve, Check power supply to correct
voltage, Dismantle suction line remove foreign
material
B. MECHANICAL TROUBLES
x
x
x
x
x
x
Misalignment due to pipe strain
Check the flange connections and eliminate strains
using elastic couplings or a method permitted
x
x
x
x
x
x
Misalignment due to improper
pump/driver setup
Check alignment and correct as necessary
x
Improperly designed foundation
Check setting of base plate: tighten, adjust, grout base
as required
