7/30/2019 Trouble-shooting CENTRIFUGAL PUMP

1/1

Fluide Design Inc, 5764 Monkland avenue, Suite 311, Montreal, Quebec, Canada H4A 1E9 Tel: 514.484.PUMP (7867)

Fax: 514.484.2294 E-mail: jchaurette@fluidedesign.com Web site: www.fluidedesign.com

DIAGNOSTIC CHART FOR CENTRIFUGAL PUMP TROUBLES

SYMPTOMS POSSIBLE CAUSES OF TROUBLEPump does not deliver water 12346111416172223

Insufficient capacity delivered 2345678910111417202223293031

Insufficient pressure delivered 51416172022293031

Pump looses prime after starting 235678111213

Pump requires excessive power 1516171819202324262729333437

Stuffing box leaks excessively 1324263233343536383940

Packing has short life 1213242628323334353637383940

Pump vibrates or is noisy 234910112123242526272830353641424344454647

Bearings have short life 24262728353641424344454647

Pump overheats and seizes 142122242728353641

LIST OF POSSIBLE CAUSES

Suction troubles1. Pump not primed2. Pump or suction pipe not completely filled with

liquid3. Suction pipe lift too high4. Insufficient margin between suction pressure and

vapor pressure5. Excessive amount of air or gas in liquid6. Air pocket in suction line7. Air leaks in suction line8. Air leaks into pump through stuffing box9. Foot valve too small10. Foot valve partially clogged11. Inlet of suction pipe insufficiently submerged12. Water seal pipe plugged13. Seal cage improperly located in stuffing box,

preventing sealing fluid entering space to form sealSystem troubles14. Speed too low15. Speed too high16. Wrong direction of rotation17. Total head of system higher than design head of

pump18. Total head of system lower than design head of

pump19. Specific gravity of liquid different from design20. Viscosity of liquid different from design criteria21. Operation at very low capacity22. Parallel operation of pumps unsuitable for such

operationMechanical troubles23. Foreign matter in impeller24. Misalignment25. Foundations not rigid

26. Shaft bent27. Rotating part rubbing on stationary part28. Bearings worn

29. Wearing rings worn30. Impeller damaged31. Casing gasket defective permitting internal leakage32. Shaft or shat sleeves worn or scored at the packing33. Packing improperly installed34. Incorrect type of packing for operating conditions35. Shaft running off center because of worn bearings o

misalignment36. Rotor out of balance resulting in vibration37. Gland too tight resulting in no flow of ;liquid to lubric

packing38. Failure to provide cooling liquid to water cooled stuf

box

39. Excessive clearance at bottom of stuffing box betwethe shaft and casing, causing packing to be forced ipump interior

40. Dirt or grit in sealing liquid, leading to scoring of shaor shaft sleeves

41. Excessive thrust caused by a mechanical failure insthe pump or by the failure of the hydraulic balancingdevice, if any

42. Excessive grease or oil in bearing housing or lack ocooling, causing excessive bearing temperature

43. Lack of lubrication44. Improper installation of antifriction bearings (damag

during assembly, incorrect assembly of stacked

bearings, use of unmatched bearings as a pair, etc.45. Dirt getting into bearings46. Rusting of bearings due to water getting into housin47. Excessive cooling of water cooled bearing resulting

condensation in the bearing housing from moisture the atmosphere