1. Speed too low.
2. Air in water.
3. Wrong impeller diameter.
4. Mechanical defects:
a) Wear rings worn.
b) Impeller damaged.
c) Packing of shaft seal damaged.
5. Wrong direction of rotation.
6. Pressure gauge in wrong location.
7. Pressure gauge off calibration, broken or stuck.
2. Air in water.
3. Wrong impeller diameter.
4. Mechanical defects:
a) Wear rings worn.
b) Impeller damaged.
c) Packing of shaft seal damaged.
5. Wrong direction of rotation.
6. Pressure gauge in wrong location.
7. Pressure gauge off calibration, broken or stuck.