Fault Finding Chart - Grundfos TP 150-310/4 Montage- Und Betriebsanleitung

12. Fault finding chart

Warning
Before removing the terminal box cover and before any removal/dismantling of the pump,
make sure that the electricity supply has been switched off and that it cannot be accidentally
switched on.
Fault
1. Motor does not run when
started.
2. Motor starter overload trips
out immediately when supply
is switched on.
3. Motor starter overload trips
out occasionally.
4. Motor starter has not tripped
out but the pump does not
run.
5. Pump capacity not constant.
6. Pump runs but gives no
water.
7. Pump runs backwards when
switched off.
8. Leakage in shaft seal.
9. Noise.
Cause
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.
a) One fuse is blown.
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.
a) Overload setting too low.
b) Supply voltage periodically too low or too high.
c) Differential pressure across pump too low, see section 9.3 Starting.
a) Supply failure.
b) Fuses blown.
c) Main contacts in motor starter are not making contact or the coil is
faulty.
d) Control circuit fuses are defective.
a) Pump inlet pressure is too low.
b) Suction pipe/pump partly blocked by impurities.
c) Pump draws in air.
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.
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.
a) Shaft seal is defective.
a) Pump is cavitating.
b) Pump does not rotate freely (frictional resistance) because of
incorrect pump shaft position.
c) Frequency converter operation:
See section 8.1 Frequency converter operation.
d) Resonance in the installation.
e) Foreign bodies in the pump.
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