8 Trouble Checklist
8.1 Trouble Check list
No liquid delivered
1.
Pump is not primed - casing and suction pipe not completely filled with liquid.
2.
Speed too low.*
3.
Discharge head too high. Check system head (particularly friction loss).
4.
Suction lift too high (suction pipe may be too small or long, causing excessive friction loss),
Check with vacuum or compound gauge.
5.
Impeller or suction pipe or opening completely plugged.
6.
Wrong direction of rotation or impeller installed backwards.
7.
Air pocket in suction line.
8.
Stuffing box packing worn or liquid seal plugged, allowing leakage of air into pump casing.
9.
Air leak in suction line.
10. Not enough suction head for hot or volatile liquids. Check carefully as this is a frequent cause of
trouble on such service.
* When directly connected to electric motors, check whether motor wiring is correct and receives full volt-
age. When directly connected to steam turbines, make sure that turbine receives full steam pressure.
Not enough water delivered
1.
Pump not primed - casing and suction pipe not completely filled with liquid.
2.
Speed too low.*
3.
Discharge head higher than anticipated. Check system head (particularly friction loss).
4.
Suction lift too high (suction pipe may be too small or long, causing excessive friction loss),
Check with vacuum or compound gauge.
5.
Impeller or suction pipe or opening partially plugged.
6.
Wrong direction of rotation or impeller installed backwards.
7.
Air pocket in suction line.
8.
Stuffing box packing worn or liquid seal plugged, allowing leakage of air into pump casing.
9.
Air leak in suction line.
10. Not enough suction head for hot or volatile liquids. Check carefully as this is a frequent cause of
trouble on such service.
11. Foot valve too small.
12. Foot valve or suction pipe not immersed deeply enough.
13. Mechanical defects:
•
Impeller clearance too great
•
Impeller damage
* When directly connected to electric motors, check whether motor wiring is correct and receives full volt-
age. When directly connected to steam turbines, make sure that turbine receives full steam pressure.
Not enough pressure
1.
Speed too low.*
2.
Air or gases in liquid.
8 Trouble Checklist
50
Model 3415 Installation, Operation, and Maintenance Manual