English (GB)
14
10. Fault finding chart
Warning
Before removing the terminal box cover and before removal/dismantling of the pump, make
sure that the power supply has been switched off and that it cannot be accidentally switched
on.
Ensure that the escaping liquid does not cause injury to persons or damage to the motor or
other components.
In hot-liquid installations, pay special attention to the risk of injury caused by scalding hot
liquid.
In cold-liquid installations, pay special attention to the risk of injury caused by the cold
liquid.
Fault Cause
1. Motor does not run when
started.
a) Supply 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 supply
is switched on.
a) Supply failure.
b) Contacts in motor starter overload are faulty.
c) Cable connection is loose or faulty.
d) Motor winding is defective.
e) Pump mechanically blocked.
f) Overload setting too low.
3. Motor starter overload trips
out occasionally.
a) Overload setting too low.
b) Supply voltage periodically too low or too high.
c) Differential pressure across pump too low.
4. Motor starter has not tripped
out but the pump does not
run.
a) Check the power supply.
b) Check fuses.
c) Check main contacts in motor starter and coil.
d) Check the control circuit.
5. Pump capacity not constant. a) Pump inlet pressure is too low.
b) Suction pipe/pump partly blocked by impurities.
c) Pump draws in air.
6. Pump runs but gives 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.
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 defective.
c) Foot or non-return valve blocked in open or partly open position.
8. Leakage in shaft seal. a) Pump shaft position is incorrect.
b) Shaft seal is defective.
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