Flowserve CPXM User Manual
Page 25

CPXM and CPXRM USER INSTRUCTIONS ENGLISH 71569101 10-08
Page 25 of 32
flowserve.com
FAULT SYMPTOM
P u m p o v e r h e a t s a n d s e i z e s
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B e a r i n g s h a v e s h o r t l i f e
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P u m p v i b r a t e s o r i s n o i s y
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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
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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
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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
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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
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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
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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
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P u m p d o e s n o t d e l i v e r l i q u i d
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PROBABLE CAUSES
POSSIBLE REMEDIES
Rotating part rubbing on stationary part internally.
Check and CONSULT FLOWSERVE, if necessary.
Bearings worn
Replace bearings.
Impeller damaged or eroded.
Replace or CONSULT FLOWSERVE for improved 
material selection. 
Stubshaft 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. 
Incorrect type of mechanical seal for operating 
conditions. 
CONSULT FLOWSERVE.
Shaft running off centre because of worn bearings 
or misalignment. 
Check misalignment and correct if necessary. If 
alignment satisfactory check bearings for excessive 
wear. 
Impeller out of balance resulting in vibration.
Abrasive solids in liquid pumped.
Internal misalignment of parts preventing seal ring 
and seat from mating properly. 
Check and CONSULT FLOWSERVE.
Mechanical seal was run dry.
Check mechanical seal condition and source of dry 
running and repair. 
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. 
Excessive thrust caused by a mechanical failure 
inside the pump. 
Check wear condition of impeller, its clearances and 
liquid passages. 
Damaged bearings due to contamination.
Check contamination source and replace damaged 
bearings. 
C. Motor electrical problems
Wrong direction of rotation.
Reverse 2 phases at motor terminal box.
Motor running on 2 phases only.
Check supply and fuses.
Motor running too slow.
Check motor terminal box connections and voltage.
Motor incorrectly wired.
Check motor terminal box connections, refer to 
motor instructions. 
