FRBH, FRBHX AND FRBHS USER INSTRUCTIONS ENGLISH 71569178 20-08
Page 49 of 60
Flowserve.com
®
7
FAULTS; CAUSES AND REMEDIES
FAULT SYMPTOM
P u mp o v er h e at s an d s ei z es
B e ar i n g s h av e s h o r t l i f e
P u mp v i b r at e s o r i s n o i sy
M ech an i c al s e al h a s sh o r t l i f e
M ech an i c al s e al l e ak s e xc e s si v e l y
P u mp r eq u i r e s ex c es s i v e p o w er
P u mp l o s e s p r i m e af t er s t ar t i n g
I n su f f i ci en t p r es su r e d ev e l o p ed
I n su f f i ci en t c ap a ci t y d el i v er ed
P u mp d o e s n o t d el i v er l i q u i d
PROBABLE CAUSES
POSSIBLE REMEDIES
A. System troubles
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Pump not primed.
Check complete filling. Vent and/or prime.
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Pump or suction pipe not completely filled with
liquid.
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Suction lift too high or level too low.
Check NPSHa>NPSHr, proper submergence,
losses at strainers/fittings.
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Insufficient margin between suction pressure and
vapour pressure.
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Excessive amount of air or gas in liquid.
Check and purge pipes and system.
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Air or vapour pocket in suction line.
Check suction line design for vapour pockets.
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Air leaks into suction line.
Check suction pipe is airtight.
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Air leaks into pump through mechanical seal,
sleeve joints, casing joint or pipe plugs.
Check and replace faulty parts.
CONSULT FLOWSERVE.
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Foot valve too small.
Investigate replacing the foot valve.
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Foot valve partially clogged.
Clean foot valve.
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Inlet of suction pipe insufficiently submerged.
Check out system design.
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Speed too low.
CONSULT FLOWSERVE.
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Speed too high.
CONSULT FLOWSERVE.
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Total head of system higher than differential head
of pump.
Check system losses.
Remedy or CONSULT FLOWSERVE.
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Total head of system lower than pump design
head.
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Specific gravity of liquid different from design.
Check and CONSULT FLOWSERVE.
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Viscosity of liquid differs from that for which
designed.
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Operation at very low capacity.
Measure value and check minimum permitted.
Remedy or CONSULT FLOWSERVE.
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Operation at high capacity.
Measure value and check maximum permitted.
Remedy or CONSULT FLOWSERVE.
B. Mechanical troubles