14
Causes & Corrective Measures
1. Pump not primed or properly vented—check that casing and
suction pipe are completely filled with liquid.
2. Speed too low—check whether motor wiring is correct and
receives full voltage or turbine receives full steam pressure.
3. System discharge head too high—check system head
(particularly friction losses).
4. Suction lift too high—check NPSH available (suction piping
too small or long may cause excessive friction losses). Check
with vacuum or compound gauge.
5. Impeller or piping obstructed—check for obstructions.
6. Wrong direction of rotation—check rotation.
7. Air pocket or leak in suction line—check suction piping for
air pockets and/or air leaks.
8. Stuffing box packing or seal worn allowing leakage of air into
pump casing—check packing or seal and replace as required.
Check for proper lubrication.
9. Not enough suction head for hot or volatile liquids—increase
suction head, consult factory.
SECTION VII—TROUBLE SHOOTING
10. Foot valve too small—install correct size foot valve.
11. Foot valve or suction pipe not immersed deep enough—
consult factory for proper depth. Use baffle to eliminate
vortices.
12. Entrained air or gases in liquid—consult factory.
13. Impeller clearance too great—check for proper clearance.
14. Impeller damaged—inspect and replace as required.
15. Rotating parts bind—check internal wearing parts for proper
clearances.
16. Shaft bent—straighten or replace as required.
17. Coupling or pump and driver misaligned—check alignment
and realign if required.
18. Impeller diameter too small—consult factory for proper
impeller diameter.
19. Improper pressure gauge location—check correct position
and discharge nozzle or pipe.
20. Casing gasket damaged—check gaskets and replace as
required.
21. Speed too high—check motor winding voltage or steam
pressure received by turbine.
22. Head lower than rating; pumps too much liquid—consult
factory. Install throttle valve, cut impeller.
23. Liquid heavier than anticipated—check specific gravity and
viscosity.
24. Stuffing box not properly packed (insufficient packing, not
properly inserted or run in, packing too tight)—check packing
and repack stuffing box.
25. Incorrect packing or mechanical seal—consult factory.
26. Damaged mechanical seal—inspect and replace as required.
Consult factory.
27. Shaft sleeve scored—remachine or replace as required.
28. Cavitation—increase NPSH available. Consult factory.
29. Pump capacity too low—consult factory for minimum
continuous flow.
30. Excessive vibration—See Section D.
31. Improper bearing lubrication or bearings worn out—inspect
and replace as required.
Problem
A. No liquid delivered,
not enough liquid
delivered, or not
enough pressure
1, 2, 3 ,4, 5, 6, 7, 8, 9,
10 11, 12, 13, 14, 18,
19, 20.
4, 5, 7, 8, 9, 11, 12, 20.
6, 13, 14, 15, 16, 21,
22, 23, 24, 31.
15, 16, 17, 28, 31.
8, 24, 25, 26, 27.
8, 24, 25, 26, 27.
15, 16, 17, 29, 30, 31.
B. Pump works a while
and then quits
C. Pump takes too much
power
D. Pump is noisy or
vibrates
E. Pump leaks
excessively at stuffing
box
F. High bearing
temperature
G. Stuffing box
overheating
Possible Causes
& Corrections
