Various problems of marine pump may be encountered during the voyage, especially the mostly used marine centrifugal pump, so the troubleshooting skill is necessary for engineer.

Failure: Pump doesn’t discharge after starting
Analysis:
1. Pump water diversion not enough or suction check valve is leaking
2. The suction filter is blocked or the check valve cannot be opened
3. The pump is not turning in the right direction or the speed is too low
4. The pump installed too high than liquid level or the suction height is too high
5. Liquid temperature is too high, there will be cavitation
Solution:
1. Re-do water diversion and stop the leakage
2. Clean the filter and disassemble the check valve
3. Correct motor rotation and check voltage
4. Reduce the suction height
5. Reduce liquid temperature

Failure: Pump capacity is not enough or low pressure
Analysis:
1. Pump’s speed too low
2. Suction tube is leaking or blocked
3. Pump internal leakage
4. Suction valve not fully opened
Solution:
1. Check voltage and motor speed
2. Check the suction pipe
3. Disassemble pump if sealing ring is worn
4. Fully open the suction valve.

Failure: Mechanical Seal Leakage
Analysis:
1. Pump shaft bended or axial deviation
2. Mechanical seal damaged
Solution:
1. Replace the shaft
2. Replace the mechanical seal

Failure: Vibration and noise
Analysis:
1. Coupling poor connected or axial deviation
2. Bearings severely worn
3. Pump seat bolts are loose
4. Pump Shaft bended
5. Motor broken
6. Cavitation
Solution:
1. Tie the coupling and correct axis
2. Replace bearing
3. Tie the bolts
4. Replace the shaft
5. Replace the motor
6. Eliminate cavitation