Flowserve CPXVC - Manual (Page 25)

CPXVC USER INSTRUCTIONS ENGLISH 26999930 03-11
Page 25 of 32 flowserve.com
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 ft 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 POSSIBLE REMEDIES
A. System troubles
Insufficient margin between suction pressure and
vapor pressure.
Check NPSH
A
> NPSH
R
, proper submergence,
losses at strainers and fittings.
Excessive amount of air or gas in liquid. Check and purge pipes and system.
Inlet of suction pipe insufficiently submerged. Check out system design.
Speed too low. CONSULT FLOWSERVE.
Speed too high. CONSULT FLOWSERVE.
Total head of system higher than differential head
of pump.
Total head of system lower than pump design
head.
Check system losses.
Remedy or CONSULT FLOWSERVE.
Specific gravity of liquid different from design.
Viscosity of liquid differs from that for which
designed.
Check and CONSULT FLOWSERVE.
Operation at very low capacity.
Measure value and check minimum permitted.
Remedy or CONSULT FLOWSERVE.
Operation at high capacity.
Measure value and check maximum permitted.
Remedy or CONSULT FLOWSERVE.
B. Mechanical troubles
Misalignment due to pipe strain.
Check the flange connections and eliminate strains
using elastic couplings or a method permitted.
Improperly designed foundation.
Check setting of soleplate: tighten, adjust, grout
base as required.
Shaft bent.
Check shaft runouts are within acceptable values.
CONSULT FLOWSERVE.
Rotating part rubbing on stationary part internally. Check and CONSULT FLOWSERVE, if necessary.
Bearings worn Replace bearings.
Wearing ring surfaces worn. Replace worn wear ring/surfaces.
Impeller damaged or eroded.
Replace or CONSULT FLOWSERVE for improved
material selection.
Leakage under sleeve due to joint failure. Replace joint and check for damage.
Shaft sleeve worn or scored or running off centre. Check and renew defective parts.
Mechanical seal improperly installed.
Check alignment of faces or damaged parts and
assembly method used.