Flowserve LNGT - Manual (Page 38)

LNGT USER INSTRUCTIONS ENGLISH 00083107 02-08
Page 38 of 48
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FAULT SYMPTOM
P u m p o ve r h e a ts 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 vi 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 ve l y
⇓ ⇓ P u m p r e q u i r e s e x c e s s i ve p ow e r
⇓ ⇓ P u m p l o s e s p r i m e a ft e r s ta 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 pa 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 ve r l i q u i d
⇓ ⇓
PROBABLE CAUSES POSSIBLE REMEDIES
z z z z z Shaft bent.
Check shaft runouts are within acceptable values.
CONSULT FLOWSERVE.
z z z z Rotating part rubbing on stationary part internally. Check and CONSULT FLOWSERVE, if necessary.
z z z z z Bearings worn. Replace bearings.
z z z Wearing ring surfaces worn. Replace worn wear ring/surfaces.
z z z Impeller damaged or eroded.
Replace or CONSULT FLOWSERVE for improved
material selection.
z Leakage under sleeve due to joint failure. Replace joint and check for damage.
z z Shaft sleeve worn or scored or running off centre. Check and renew defective parts.
z z z Mechanical seal improperly installed.
Check alignment of faces or damaged parts and
assembly method used.
z z z Incorrect type of mechanical seal for operating
conditions.
CONSULT FLOWSERVE.
z z z z z Shaft running off centre because of worn bearings
or misalignment.
Check misalignment and correct if necessary. If
alignment satisfactory check bearings for excessive
wear.
z z z z z Impeller out of balance resulting in vibration.
z z z Abrasive solids in liquid pumped.
z z Internal misalignment of parts preventing seal ring
and seat from mating properly.
Check and CONSULT FLOWSERVE.
z z Mechanical seal was run dry.
Check mechanical seal condition and source of dry
running and repair.
z z Internal misalignment due to improper repairs
causing impeller to rub.
Check method of assembly, possible damage or
state of cleanliness during assembly.
Remedy or CONSULT FLOWSERVE, if necessary.
z z z Excessive thrust caused by a mechanical failure
inside the pump.
Check wear condition of impeller, its clearances and
liquid passages.
z z Excessive grease in ball bearings. Check method of regreasing.
z z Lack of lubrication for bearings.
Check hours run since last change of lubricant, the
schedule and its basis.
z z Improper installation of bearings [damage during
assembly, incorrect assembly, wrong type of
bearing etc].
Check method of assembly, possible damage or
state of cleanliness during assembly and type of
bearing used. Remedy or CONSULT
FLOWSERVE, if necessary.
z z Damaged bearings due to contamination. Check contamination source and replace damaged
bearings.
C. MOTOR ELECTRICAL PROBLEMS
z z z z Wrong direction of rotation. Reverse 2 phases at motor terminal box.