SAMCO CSR, Installation Manual, Page: 9 / 12

9
Troubleshooting
No liquid delivered
CAUSES CURES
1. Lack of prime
2. Loss of prime
3. Suction lift too high
4. Discharge system head too high
5. Speed too low
6. Wrong direction of rotation
7. Impeller completely plugged
Fill pump and suction pipe completely with liquid.
Check for leaks in suction pipe joints and fittings; vent
casing to remove accumulated air.
If no obstruction at inlet, check for pipe friction losses.
However, static lift may be too great. Measure with
mercury column or vacuum gauge while pump operates.
If static lift is too high, liquid to be pumped must be
raised or pump lowered.
Check pipe friction losses. Larger discharge piping
may correct condition. Check that valves are wide open.
Check whether motor is directly across-the-line and
receiving full voltage. Alternatively, frequency may be
too low; motor may have an open phase.
Check motor rotation with directional arrow on pump
casing. Wrong rotation will cause pump damage.
Dismantle pump or use piping hand hole to clean impeller.
Not enough liquid delivered
8. Air leaks in suction piping
9. Air leaks in stuffing box
10. Speed too low
11. Discharge system head too high
12. Suction lift too high
13. Impeller partially plugged
14. Cavitation; insufficient NPSH
(depending on installation)
15. Defective impeller
16. Defective packing
If liquid pumped is water or other non-explosive material,
and explosive gas or dust is not present, test flanges for
leakage with a flame or match. For such liquids as
gasoline, suction line can be tested by shutting off or
plugging inlet and putting line under pressure. A gauge
will indicate a leak with a drop of pressure.
Increase seal lubricant pressure to above atmosphere.
See item 5.
See item 4.
See item 3.
See item 7.
a. Increase positive suction head on pump by lowering pump
or increasing suction pipe size or raising fluid level.
b. Sub-cool suction piping at inlet to lower entering liquid
temperature.
c. Pressurise suction vessel.
Inspect impeller. Replace if damaged or vane sections
badly eroded.
Replace packing and sleeves if badly worn.