Flowserve MN - Manual (Page 44)

MN USER INSTRUCTIONS ENGLISH 71569189 11/04
Page 44 of 49
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7 FAULTS; CAUSES AND REMEDIES
FAULT SYMPTOM
P u m p o ve r h e a ts a n d s e iz e s
⇓ ⇓ B e a r i n g s h ave s h o r t l i f e
⇓ ⇓ P u m p vi b r a t e s o r i s n o i sy
⇓ ⇓ M e c h a n i c al s e a l / G l a n d pa c k i n g h a s sh o r t l i f e
⇓ ⇓ M e c h a n i c al s e a l / G l a n d le a k s e xc e s s ive l y
⇓ ⇓ P u m p r e q u i re s e x c es s i ve p ow e r
⇓ ⇓ P u m p l o s e s p r i m e a ft e r sta r t i n g
⇓ ⇓ I n s u f f i c i e n t d i s c h a r g e pre s s u r e d e ve 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 ve r e d
⇓ ⇓ P u m p d o e s no t d e l i ve r l i q u i d
⇓ ⇓
PROBABLE CAUSES POSSIBLE REMEDIES
A. System troubles
Pump not primed.
Pump or suction pipe not completely filled with
liquid or valves not fully open.
Check & fill completely. Vent and/or prime. Open
the valves fully.
Suction lift too high or level too low.
Insufficient margin between suction pressure and
vapor pressure.
Check NPSH
A
>NPSH
R
, proper submergence, losses
at strainers and fittings.
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. Refer to Seal User
instructions/ Consult Flowserve, if needed.
System design pressure requirement is greater
than the pump can deliver.
Consult Flowserve.
Impeller, casing piping partially /fully clogged. Clean the effected area and prevent this happening
again.
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.
Total head of system lower than pump design head.
Check system losses. Remedy or Consult
Flowserve.
Specific gravity of liquid different from design.
Viscosity of liquid differs from the designed.
Check and Consult Flowserve.
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 and /or improper
piping.
Check setting of baseplate: tighten, adjust, grout
base as required. Check piping.
Shaft bent. Check shaft runouts are within acceptable values.
Rotating part rubbing on stationary part internally. Check/locate the problem or call Flowserve.
Bearings worn Replace bearings.