TROUBLE SHOOTING PUMP NOT STARTING

MARINESHELF publishes articles contributed by seafarers and other marine related sites solely for the benefit of seafarers .All copyright materials are owned by its respective authors or publishers.A. Pump and motor cannot be actuated:

1. Impeller or shaft blocked.
2. Motor fault.

B. Motor running but no pumping effect:

1. Motor rotation is not transmitted through coupling.
2. Discharge valve closed.
3. Non-return valve or other valves are closed.
4. Suction line closed or filter clogged.
5. Air in pump casing.
6. Suction line leaking.
7. Shaft seal leaking.
8. Bottom valve defective.
9. Suction lift too high.
10. Priming pump defective.

C. Insufficient capacity:

1. Wrong direction of rotation.
2. Number of revolutions too low.
3. Counter-pressure too high.
4. Suction line or impeller partly clogged.
5. Air in pump casing.
6. Air in pumping medium.
7. Suction lift too high (inlet pressure too low).
8. Capitation.
9. Suction line leaking.
10. Shaft seal leaking.
11. Pump worn out.

D. Pump pressure too high:

1. Number of revolutions too high.
2. Impeller oversized.
3. Too many pressure stages.
4. Specific gravity of pumping medium too high.
5. Viscosity of pumping medium too low.
6. Inlet pressure too high.
7. Manometer defective.

E. Capacity too large:

1. Number of revolutions too high.
2. Impeller diameter too big.
3. Counter-pressure too low.

F. Discharge head too low:

1. Number of revolutions too low.
2. Impeller diameter too small.
3. Too few pressure stages.
4. Specific gravity of pumping medium too low.
5. Viscosity of pumping medium too high.
6. Manometer defective.

G. Power consumption too large:

1. Motor too small.
2. Motor fault.
3. Capacity too large.
4. Counter-pressure too low.
5. Stuffing-box tightened too much.
6. Shaft ends out of alignment.
7. Electricity supply incorrect (voltage, amperage, frequency).

H. Pump output decreases or stops: 
1. Suction line leaking.
2. Shaft seal leaking.
3. Increasing suction lift.
4. Filter clogged.
5. Cavitation.
I. Irregular running:
1. Bearings defective.
2. Motor fault.

K. Increasing noise level:
1. Beginning cavitation.
2. Air in pumping medium.
3. Capacity too large.
4. Clamping to base loosened.
5. Base bolts loosened.
6. Influences from pipe connections or base.

L. Leaks: 
1. Cracks in pump casing.
2. Faulty assembly of pump.
3. Pipe connections leaking.
4. Shaft seal leaking (in case of soft stuffing-box packing minor leaks are necessary).

M. Bearing temperature too high:
1. Faulty lubrication or wrong lubricant.
2. Deficient pump alignment.
3. Influences from pipe line.
4. Coupling distance wrong.
5. Shaft bent.
6. Foreign bodies or impurities in bearings.

N. Pump wears out quickly:
1. Wrong materials in relation to pumping medium.
2. Cavitation.
3. Stuffing-box tightened too much.
4. Shaft bent.
5. Deficient alignment.
6. Influences through pipe line.

O. Stark vibrations:
1. Foreign bodies in pump.
2. Motor out of balance.
3. Other influences.