WIK USER INSTRUCTIONS ENGLISH BO2662 5/09
Page 69 of 76
7
FAULTS; CAUSES AND
REMEDIES
Unnecessarily long shutdowns and unnecessary
expense may be avoided by careful and periodic
observation of the pump (see section 6). That is, by
knowing the operational behavior of the pump, which
in part stems from frequent observation, an irregular
condition is more apt to be detected in its early stage,
permitting prompt corrective action before it worsens
and causes severe damage. Usually, any behavioral
change reveals at least whether its cause is
mechanical, electrical or hydraulic, thus narrowing
the troubleshooter’s task.
Most troubles are related to the hydraulic conditions
in the suction system. Here, any condition that
causes the suction pressure to drop below that
required in the eye of the inlet impeller generates
trouble; typically where the net positive suction head
(NPSH) is less than required (see section 10).
Bullet point table
Fault; Causes and Remedies
below lists frequently asked fault symptom on the
left hand side, with their possible causes and
possible remedies on the right hand side. Should
questions arise, contact your nearest Flowserve
Sales Office.
When venting or draining pumps
which contain toxic, flammable, and/or high
temperature fluids, ensure that the vented or
drained fluid is piped to a safe collector which will
prevent release of the fluid into the surrounding
area. Failure to do so can result in equipment
damage, personnel injury, or death.
FAULT SYMPTOM
Pu m p o v e rh e a ts a n d s e i z e s
B e a ri n g s h a v e s h o rt l i f e
Pu m p v i b ra 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 rt 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
Pu m p r e q u i re s e x c e s s i v e p o w e r
Pu m p l o s e s p ri m e a ft e r s ta rt 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
Pu m p d o e s n o t d e l i v e r l i q u i d
PROBABLE 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 NPSHa>NPSHr, proper
submergence, losses at strainers/fittings.
Insufficient margin between suction
pressure and vapor pressure.
Excessive amount of air or gas in liquid. Check and purge pipes and system.
Air or vapor pocket in suction line.
Check suction line design for vapor
pockets.
Air leaks into suction line.
Check suction pipe is airtight.
Air leaks into pump through mechanical
seal, sleeve joints, casing joint or pipe
plugs.
Check and replace faulty parts.
CONSULT FLOWSERVE.