1. Pump does not start: Check the starting system.
2. The speed is too low: check whether the engine is running at the required power/speed.
3. The sum of the suction and discharge heads is greater than the rated head of the pump: check the total head requirements against the performance curve of the pump.
4. The impeller is completely blocked: remove the sundries in the impeller.
5. Suction hose or filter clogged and/or leaking: Remove any debris from the suction hose and filter. Repair any leaks in the suction hose.
6. Worn impellers and/or wear rings: inspect and replace as necessary.
7. Worn mechanical seal: check and replace if necessary.