Flowserve VTP Wet Pit - Manual (Page 56)

VERTICAL TURBINE PUMPS (VTPS) CENTRIFUGAL PUMPS ENGLISH 71569224 – 10-13
Page 56 of 76 flowserve.com
7 FAULTS; CAUSES AND REMEDIES
FAULT SYMPTOM
P u m p o ve r h e a t s a n d s e i z 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 s y
 M e c h a n i c al s e a l h a s s h or t l i f e
 M e c h a n i c al s e a l le a k s ex c e s s i ve l y
 P u m p r e q u i r e 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 f t er st 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 eve 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 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
 POSSIBLE CAUSES POSSIBLE REMEDIES
A. SYSTEM PROBLEMS
   Pump not submerged. Check requirements/liquid level. Vent and/or prime.
    Impeller not adjusted or loose on shaft. See PART/2-Section A7 for proper impeller adjustment.
   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.
 Line check valve backward/stuck. Reverse chuck valve /free the valve.
 Unit running backwards. See start up instruction. Check motor phase/wiring
   Air or vapor pocket in suction line. Check suction line design for vapor pockets.
  Air leaks into suction line. Check suction pipe is airtight.
    Intake strainer or impeller plugged or pump
in mud or sand.
Start and stop several times or use line pressure if
available to back flush or pull pump to clean.
   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 or consult Flowserve.

Total system head is lower than pump
design head.
  Specific gravity of liquid different from
design.
Check and consult Flowserve.
Check the pump design for the type of liquid to be
handled. Consult Flowserve.
    Viscosity of liquid differs from the designed.
  Operation at very low capacity. Measure. Check minimum permitted. Consult Flowserve.
    Operation at high capacity.
Measure value and check maximum permitted. Consult
Flowserve.
B. MECHANICAL PROBLEMS
      Misalignment due to pipe strain.
Check the flange connections and eliminate strains using
elastic couplings or a method permitted.

Improperly designed foundation./Loose
fasteners. Check setting of base plate. Tighten, adjust, grout base as
required. Check fasteners and torque.
     Shaft bent. Check shaft run outs. Consult Flowserve.
     Rotating part rubbing on stationary part. Check. Consult Flowserve, if necessary.
     Bearings worn. Replace bearings.
   Wearing ring surfaces worn. Replace worn wear ring/surfaces.