I. No liquid delivered by pump
Possible causes
1. There is an air leak in the suction pipeline or the stuffing box.
2. The impeller rotates in a reverse motion or there is damage to the impeller.
3. The suction pipeline is clogged.
Solutions
1. Repair the leaky part.
2. Check the rotational direction or replace the damaged impeller.
3. Clear the clogged pipe.

II. Pump shaft takes too much power.
Possible causes
1. Packing is too tight, which leads to stuffing box overheating.
2. There is severe friction within the pump
3. Damaged bearing
4. The drive belt is too tight.
5. Too much flow in the pump
6. High rotational speed while pumping slurries with high specific gravity
7. Misalignment between the motor shaft and pump shaft
Solutions
1. Loosen the gland nut
2. Eliminate friction
3. Replace bearing
4. Loosen the belt
5. Adjust the pump operating conditions
6. Adjust the rotational speed
7. Realign the motor shaft with the pump shaft.

III. Bearing overheats.
Causes
1. Too much or little lubricating grease
2. There are impurities in the lubricating grease.
3. Bearing damages.
Solutions
1. Apply lubricating grease reasonably.
2. Replace the grease with a new one
3. Use new bearing

IV. Gland packing leaks excessively.
Causes
1. Severely worn gland packing
2. Severely worn shaft sleeve
3. There are impurities in the shaft sealing water.
Solutions
1. Use new packing material
2. Use new shaft sleeve
3. Use clean shaft sealing water

V. Pump vibrates, making loud noise.
Causes
1. The bearing damages.
2. Unbalanced impeller
3. Air leaks into the suction. Or the suction side is clogged.
4. Uneven flow. The pump does not prime.
Solutions
1. Use new bearing
2. Use new impeller
3. Eliminate air leak, clear the clogged suction part
4. Ensure a constant feed rate