13
Troubleshooting
Risk of electrical shock and possible unexpected starts. Disconnect all power to the pump before
servicing or working on pump. Make sure that power is locked out and that pump cannot be accidentally started.
Problem
Cause
1. Motor does not run when
started
A. Power failure
B. Fuses blown
C. Motor starter overload has tripped out
D. Main contacts in motor starter are not making contact or the coil is faulty
E. Control circuit fuses are defective
F. Motor is defective
2. Motor starter overload trips
out immediately when power
supply is switched on
A. One fuse has blown
B. Contacts in motor overload relay are faulty
C. Cable connections are loose or faulty
D. Motor winding is defective
E. Pump mechanically blocked
F. Overload setting is too low
3. Motor starter overload trips
out occasionally
A. Overload setting is too low
B. Low voltage at peak times
4. Motor starter has not tripped
out but the motor does not run
A. Check 1 A), B), D,) and E)
5. Pump capacity is not constant
A. Pump inlet pressure is too low
B. Suction pipe/pump partly blocked
C. Pump is sucking air
6. Pump runs but gives no water
A. Suction pipe/pump blocked
B. Foot or non-return valve is blocked in closed position
C. Leakage in suction pipe
D. Air in suction pipe or pump
E. Motor rotates in the wrong direction
7. Pump runs backwards when
switched off
A. Leakage in suction pipe
B. Foot or non-return valve is defective
C. Foot valve is blocked in open or partly open position
D. Non return valve leaks or is blocked in open or partly open position
E. Discharge valve is defective
8. Leakage from shaft seal
A. Pump shaft position is incorrect
B. Shaft seal is defective
9. Noise
A. Cavitation is occurring in the pump
B. Pump does not rotate freely (That is, there is increased frictional resistance)
because of incorrect shaft position