Faults, causes and remedies, 7faults, causes and remedies – Flowserve APKD User Manual

Page 44

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APKD DOUBLE-CASE, DOUBLE-SUCTION USER INSTRUCTIONS 26999903 07-13

Page 44 of 55

flowserve.com

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

P u m p w i ll n ot r u n

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 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 re s e x c es s i ve p ow e r

M o t o r O ve r l o a d e d

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 pa c i t y d e l i ve r e d

P u m p r u n s bu t d o e s n o 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.

Check impeller adjustment. See Section 5.3 for details.

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.

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 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.

Impeller damaged or eroded.

Replace. or consult Flowserve for an upgrade.

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