Goulds Pumps 3311 - IOM - Manual (Page 30)

30
8 Locating Troubles
8.1
Troubles and possible causes
Trouble Cause
Remedial action
Wrong direction of rotation. Re-connect the motor.
Discharge pressure too high. Check the system for contaminants, re-adjust the duty
point.
Suction lift too high or insufficient NPSHA. Check liquid levels,
open suction side shut-off valves,
clean suction side filter / dirt trap.
Pump / pipeline insufficiently filled with liquid. Vent and re-fill the pump / pipeline.
Sealing clearances too great due to wear. Replace worn pump components, or install wear
rings.
Leakage in casing or suction pipework. Replace casing seal,
check flange connections.
Insufficient liquid
delivered
Impellers or diffusers clogged. Disassemble the pump, clean the impellers or
diffusers.
Suction lift too high or insufficient NPSHA. Check liquid levels,
open suction side shut-off valves,
clean suction side filter / dirt trap.
Leakage in casing, shaft seal, foot valve or
suction pipework. Replace casing seal, check shaft seal, check flange
connections.
Insufficient
suction
performance of
pump
Loose or clogged parts in the pump. Open the pump and clean it.
Casing bolts not tight enough. Check tightening torque of the tie bolts.
Defective mechanical seal. Check the sealing surfaces and secondary seals of the
mechanical seal, replace damaged components.
Pump leakage
Damaged seals. Replace seals.
Discharge side valve closed. Open discharge side valve.
Suction lift too high or insufficient NPSHA Check liquid levels,
open suction side shut-off valves,
clean suction side filter / dirt trap.
Temperature
increase in the
pump
Pump / pipeline insufficiently filled with liquid. Vent and re-fill the pump / pipeline.
Internal components worn. Renew worn parts.
Excessive clearances. Install wear rings, diaphragm bushes.
Increase in axial thrust. Check clearances, throttling gap and balancing line.
Insufficient, too much, contaminated or
unsuitable lubricant. Add, reduce or replace lubricant.
Bearings worn. Replace bearings.
Shaft sealing area insufficiently cooled. Check cooling lines, remove any deposits in the
cooling liquid container.
Coupling misaligned or coupling components
worn. Align or replace.
Pump distorted, or sympathetic vibrations in the
pipework. Check pump and pipework fastening. Install
vibration-absorbing pipework support.
Increase in bearing
temperature
Flow rate too low / too high. Ensure minimum flow / throttle discharge side shut-
off valve.
Suction lift too high or insufficient NPSHA. Check liquid levels,
open suction side shut-off valves,
clean suction side filter / dirt trap.
Pump / pipeline insufficiently filled with liquid. Vent and re-fill the pump / pipeline.
Base of the pump not level. Pump distorted. Check pump installation and adjustment.
Unsteady running
of pump, excessive
noise
Foreign substances in the pump. Open the pump and clean it.
Requirements as to pumping conditions not met. Check the pumping conditions against the data sheet.
Base of the pump not level. Pump distorted. Check the installation and alignment of the pump.
Motor circuit
breaker switches
off
Foreign substances in the pump. Open the pump and clean it.