HDX USER INSTRUCTIONS ENGLISH 85392696 - 01/11
Page 44 of 60
7 FAULTS; CAUSES AND REMEDIES
FAULT SYMPTOM
P u m p o ve r h e a ts 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 vi 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 ve 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 ve p ow 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 ta 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 pa 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 ve r l i q u i d
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PROBABLE CAUSES
POSSIBLE REMEDIES
A. System troubles
z
z
Pump not primed.
z
z
z
z
Pump or suction pipe not completely filled with
liquid.
Check complete filling. Vent and/or prime.
z
z
z
z
Suction lift too high or level too low.
z
z
z
z
Insufficient margin between suction pressure and
vapour pressure.
Check NPSHa>NPSHr, proper submergence,
losses at strainers/fittings.
z
z
z
Excessive amount of air or gas in liquid.
Check and purge pipes and system.
z
z
z
Air or vapour pocket in suction line.
Check suction line design for vapour pockets.
z
z
Air leaks into suction line.
Check suction pipe is airtight.
z
z
Air leaks into pump through mechanical seal,
sleeve joints, casing joint or pipe plugs.
Check and replace faulty parts.
CONSULT FLOWSERVE.
z
z
Foot valve too small.
Investigate replacing the foot valve.
z
z
Foot valve partially clogged.
Clean foot valve.
z
z
z
z
Inlet of suction pipe insufficiently submerged.
Check out system design.
z
z
z
Speed too low.
CONSULT FLOWSERVE.
z
Speed too high.
CONSULT FLOWSERVE.
z
z
z
Total head of system higher than differential head
of pump.
z
Total head of system lower than pump design
head.
Check system losses.
Remedy or CONSULT FLOWSERVE.
z
Specific gravity of liquid different from design.
z
z
z
Viscosity of liquid differs from that for which
designed.
Check and CONSULT FLOWSERVE.
z
z
Operation at very low capacity.
Measure value and check minimum permitted.
Remedy or CONSULT FLOWSERVE.
z
z
z
Operation at high capacity.
Measure value and check maximum permitted.
Remedy or CONSULT FLOWSERVE.
B.
Mechanical
troubles
z
z
z
z
z
z
Misalignment due to pipe strain.
Check the flange connections and eliminate strains
using elastic couplings or a method permitted.
z
Improperly designed foundation.
Check setting of baseplate: tighten, adjust, grout
base as required.
z
z
z
z
z
Shaft bent.
Check shaft runouts are within acceptable values.