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English (US)
24. Fault finding
* In twin-head pump installations, the backup pump will often rotate slowly.
Warning
Before removing the terminal box cover or
removing/dismantling the pump, make sure that
the power supply has been switched off for at
least 5 minutes. Make sure that the power supply
cannot be accidentally switched on.
Warning
Make sure that the escaping water does not
cause injury to persons or damage to the
equipment.
Fault Cause/remedy
1. Motor does not run when started. a) Supply failure.
b) Fuses blown.
c) Motor defective.
2. Motor alarm when the power supply is switched on. a) Supply failure.
b) Cable connection loose or faulty.
c) Motor winding defective.
d) Pump mechanically blocked.
3. Occasional motor alarm. a) Supply voltage periodically too low or too high.
b) Differential pressure across pump too low.
4. No motor alarm, but the pump does not run. a) Check the power supply.
b) Check fuses.
5. Pump capacity not constant. a) Pump inlet pressure too low.
b) Suction pipe/pump partly blocked by impurities.
c) Pump draws in air.
6. Pump runs but delivers no water. a) Suction pipe/pump blocked by impurities.
b) Foot or non-return valve blocked in closed position.
c) Leakage in suction pipe.
d) Air in suction pipe or pump.
7. Pump runs backwards when switched off.* a) Leakage in suction pipe.
b) Foot or non-return valve defective.
c) Foot or non-return valve blocked in open or partly open position.
8. Leakage in shaft seal. a) Shaft seal defective.
9. Noise. a) Pump is cavitating.
b) Pump does not rotate freely (frictional resistance) because of incorrect
pump shaft position.
c) Resonance in the installation.
d) Foreign bodies in the pump.
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