- Suction pipe, foot valve choked.
- Suction pipe not sufficiently submerge
- Incorrect Layout of Suction Line.
- Joints in the suction line not leak-proof.
- Air leaking through the Suction line & Stuffing Box.
- Suction lift too high.
- Suction head too low.
- Delivery liquid too viscous.
- Impeller clogged.
- Lantern Ring in Stuffing box is not positioned below the sealing liquid inlet.
- Packing not suitable for operating conditions.
- Type of pump unsuitable.
- Temperature of delivery liquid too high.