7 faults; causes and remedies – Flowserve WMV IDP User Manual

Page 22

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WMV, WMVS USER INSTRUCTIONS ENGLISH 26999970 10-12

Page 22 of 28

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

POSSIBLE CAUSES

POSSIBLE REMEDIES

A. System troubles

Pump not primed.

Check complete filling. Vent and/or prime.

Pump or suction pipe not completely filled with liquid.

Suction lift too high or level too low.

Check NPSH

A

> NPSH

R

, proper submergence,

losses at strainers and fittings.

Insufficient margin between suction pressure and vapour

pressure.

Excessive amount of air or gas in liquid.

Check and purge pipes and system.

Air or vapour pocket in suction line.

Check suction line design for vapour pockets.

Air leaks into suction line.

Check suction pipe is airtight.

Air leaks into pump through mechanical seal, sleeve
joints, casing joint or pipe lugs.

Check and replace faulty parts.
CONSULT FLOWSERVE.

Foot valve too small.

Investigate replacing the foot valve.

Foot valve partially clogged.

Clean foot valve.

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.

Check system losses.
Remedy or CONSULT FLOWSERVE.

Total head of system lower than pump design head.

Specific gravity of liquid different from design.

Check and CONSULT FLOWSERVE.

Viscosity of liquid differs from that for which designed.

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 baseplate: 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.

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