Filter
Top Products
UB USER INSTRUCTIONS ENGLISH 71569247 07-04
Page 27 of 32
®
7 FAULTS; CAUSES AND REMEDIES
FAULT SYMPTOM
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
⇓
⇓⇓
⇓
⇓
⇓⇓
⇓
PROBABLE CAUSES POSSIBLE REMEDIES
A. SYSTEM TROUBLES
z
zz
zz
zz
z
Pump not primed. Check complete filling.
z
zz
zz
zz
zz
zz
zz
zz
z
Pump or suction pipe not completely filled with
liquid.
Check and complete filling.
z
zz
zz
zz
zz
zz
zz
zz
zz
zz
z
Suction lift too high or level too low.
Check NPSH
A
>NPSH
R
, proper submergence,
losses at strainers and fittings.
z
zz
zz
zz
zz
zz
z
Excessive amount of air or gas in liquid. Check and purge from pipes.
z
zz
zz
zz
zz
zz
z
Air or vapour pocket in suction line. Check suction line design for pockets.
z
zz
zz
zz
z
Air leaks into suction line. Check airtight pipe then joints and gaskets.
z
zz
zz
zz
z
Air leaks into pump through mechanical seal,
sleeve joints, casing joint or pipe lugs.
Check airtight assembly then joints and gaskets.
z
zz
zz
zz
z
Foot valve too small. Investigate replacing the foot valve.
z
zz
zz
zz
z
Foot valve partially clogged. Clean foot valve.
z
zz
zz
zz
zz
zz
zz
zz
z
Inlet of suction pipe insufficiently submerged. Check cut out system design.
z
zz
zz
zz
zz
zz
z
Total head of system higher than differential head
of pump.
Check discharge head and head losses in
discharge pipe at the valve settings. Check back
pressure is not too high.
z
zz
z
Total head of system lower than pump design
head.
Throttle at discharge valve or ask Flowserve if the
impeller can be trimmed.
z
zz
z
Specific gravity of liquid different from design. Consult Flowserve.
z
zz
zz
zz
zz
zz
z
Viscosity of liquid differs from design. Consult Flowserve.
z
zz
zz
zz
z
Operation at very low capacity. Measure value and check minimum permitted.
z
zz
zz
zz
zz
zz
z
Operation at high capacity. Measure value and check maximum permitted.
B. MECHANICAL TROUBLES
z
zz
zz
zz
zz
zz
zz
zz
zz
zz
zz
zz
z
Misalignment due to pipe strain.
Check the flange connections and eliminate
strains using elastic couplings or a method
permitted.
z
zz
z
Improperly designed foundation.
Check setting of baseplate: tighten, adjust, grout
base as required.
z
zz
zz
zz
zz
zz
zz
zz
zz
zz
z
Shaft bent. Check shaft runouts within acceptable values.
z
zz
zz
zz
zz
zz
zz
zz
z
Rotating part rubbing on stationary part internally.
Check for signs of this and consult Flowserve if
necessary.
z
zz
zz
zz
zz
zz
zz
zz
zz
zz
zz
zz
z
Bearings worn Replace bearings.
z
zz
zz
zz
zz
zz
z
Wearing ring surfaces worn. Replace worn wear ring/surfaces.