Flowserve WDX - Manual (Page 38)

WDX USER INSTRUCTIONS ENGLISH 71576322 06-05
Page 38 of 46
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7 FAULTS; CAUSES AND REMEDIES
FAULT SYMPTOM
Pu m p o v er h eat s an d s ei z e s
  B earin g s h av e sh o rt l if e
  Pu mp v ib rat es o r is n o i s y
  M ech an ic al se al h a s sh o rt lif e
  M ech an ic al se al l ea ks ex ce ssiv el y
  Pu mp req u ir es ex ces siv e p o wer
  Pu mp lo se s p rim e af t er st art in g
  In su f f icien t p re ssu r e d ev elo p ed
  In su f f icien t c ap ac it y d el iv ered
  Pu mp d o es n o t d e liv er liq u id
 
PROBABLE C AUSES POSSIBLE REMEDIES
A. Syst em troubles
  Pump not primed.
    Pump or suction pi pe not compl etel y filled with
liquid.
Chec k compl ete filling. Vent and/ or prime.
    Suction lift too high or level too low.
    Insufficient margin between s uction pr essure and
vapour press ure.
Chec k NPSH
A
>NPSH
R
, proper submergence,
losses at strainers and fit tings.
   Exc essi ve amount of air or gas in liquid. Chec k and purge pipes and s yst em.
   Air or vapour poc ket in s uction line.
Chec k suc tion line design f or vapour poc kets.
  Air leaks int o suc tion line. Chec k suc tion pipe is airtight.
  Air leaks int o pump t hrough mechanical s eal,
sleeve j oints, c asing joint or pi pe plugs. Chec k and r eplac e f ault y parts.
CONSULT FLO WSERVE.
 
Foot valve t oo s mall. Investigat e repl acing the f oot val ve.
  Foot valve partiall y clogged. Clean f oot val ve.
    Inlet of s uction pipe ins ufficientl y submerged.
Chec k out s yst em design.
   Speed too l ow.
CONSULT FLO WSERVE.
 Speed t oo high. CONSULT FLO WSERVE.
   Total head of s ystem higher than differenti al head
of pump.
 Total head of s yst em l ower than pump design
head.
Chec k s yst em l osses.
Remedy or CONSU LT FLOWSERVE.

Specific gravit y of liquid differ ent from design.
   Viscosity of liquid differs from that f or which
designed.
Chec k and CON SULT F LOWSERVE.
 
Operati on at very low capacit y.
Measure value and c hec k mini mum permit ted.
Remedy or CONSU LT FLOWSERVE.
  
Operati on at high capacit y.
Measure value and c hec k maximum per mitted.
Remedy or CONSU LT FLOWSERVE.
B. Mechani cal troubles
     
Misalignment due t o pipe str ain.
Chec k t he fl ange c onnecti ons and elimi nat e strai ns
using elastic c ouplings or a method permit ted.

Improperl y designed foundati on.
Chec k setting of bas epl ate: tighten, adjus t, grout
base as required.
    
Shaf t bent .
Chec k shaft runouts are within acc ept able values.
CONSULT FLO WSERVE.