Faults; Causes And Remedies - Flowserve Centrifugal Pump 8-UB-1 Installation & Operation Instruction

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7 FAULTS; CAUSES AND REMEDIES

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