Flowserve Durco Mark 3 ISO Frame Mounted - Manual (Page 36)

DURCO MARK 3 ISO FRAME MOUNTED ENGLISH 85392719 12-14
Page 36 of 52
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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 f t 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 or filled with liquid. Check complete filling.
   
Pump or suction pipe not completely filled with
liquid. (Where not a self-priming arrangement.)
Vent and/or prime.
    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
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 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.