Flowserve HED Worthington - Manual (Page 45)

HED/HED-DS USER INSTRUCTIONS ENGLISH 85392695 – 06/14
Page 45 of 64
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
  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 vi 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 ve l y
  P u m p r e q u i r e s e x c e s 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 s ta 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 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 v e r e d
  P u m p d o e s n o t d e l i ve 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
vapour pressure.
   Excessive amount of air or gas in liquid. Check and purge pipes and system.
   Air or vapour pocket in suction line. Check suction line design for vapour 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.
  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.