Excessive shaft power          

Rubbing between impeller and liner plate

Excessive system resistance

Flow rate too high

Adjust clearance between impeller and liner plate

Remove blockage

Adjust gate valve to reduce flow rate

Insufficient head

Excessive clearance between impeller front end and pump casing

Large particles blocking impeller passages

Severe wear of impeller and liner plate

Adjust clearance between impeller and pump casing

Disconnect suction pipe and clean flow passages

Replace impeller and liner plate; adjust their clearance

Bearing overheating

Improper oil quantityContaminants in oil

Bearing wear or improper clearance

Increase or reduce lubricating oil quantity

Replace lubricating oil

Replace bearing or adjust bearing clearance

Vibration

Impeller out of balance

Insufficient feed flow or air ingress into pump cavityRubbing between impeller and pump casing

Replace impeller or balance it to specified requirements

Increase feed flow or check all sealing points to ensure air-tightness

· Adjust clearance between impeller and pump casing

Leakage

Seal ring damaged

Shaft seal water not supplied or not meeting specified requirements

Packing worn                               

Inspect all sealing points and replace seal rings

Supply shaft seal water meeting specified requirements

Replace packing and tighten to specified requirements