TROUBLE SHOOTING
Between regular maintenance inspections, be alert for signs of motor or pump trouble. Common symptoms are listed below. Correct any trouble immediately and AVOID COSTLY REPAIR AND SHUTDOWN.
CAUSES
1.Lack of prime.
2.Loss of prime.
3.Suction lift too high (a negative suction gauge reading).
4.System static head too high.
5.Speed too low.
6.Wrong direction of rotation.
7.No rotation.
8.Impeller loose on shaft.
9.Impeller completely plugged.
10.System head or required discharge head too high.
11.Air leaks in suction piping.
12.Air leaks in stuffing box.
13.Speed too low.
14.Discharge head too high.
15.Suction lift too large.
CURES
No Liquid Delivered
Fill pump and suction pipe completely with liquid.
Check for leaks in suction pipe joints and fittings; vent casing to remove accumulated air. Check mechanical seal or packing.
If there is no obstruction at inlet and suction valves are open, 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 with factory to see if a larger impeller can be used; otherwise, cut pipe losses or increase speed – or both, as needed. But be careful not to overload driver by more than the service factor.
Check whether motor is directly
Check motor rotation with directional arrow on pump casing. If rotation is correct with arrow, check the relationship of the impeller with casing. (This will require removing casing upper half.)
See Figure 10 on page 23.
Check power, coupling, line shaft and shaft keys.
Check key, locknut and set screws.
Dismantle pump and clean impeller.
Check pipe friction losses. Large piping may correct condition. Check that valves are wide open.
Not Enough Liquid Delivered
If liquid pumped is water or other
Replace packing and sleeves if appropriate or increase seal lubricant pressure to above atmosphere.
See item 5.
See item 10.
See item 3.
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