English (GB)
13
12. Fault finding
13. Disposal
This product or parts of it must be disposed of in an
environmentally sound way:
1. Use the public or private waste collection service.
2. If this is not possible, contact the nearest Grundfos company
or service workshop.
Subject to alterations.
Warning
Before removing the terminal box cover and before removing/dismantling the pump, make sure that the power
supply has been switched off and that it cannot be accidentally switched on.
Fault Cause Remedy
1. Motor does not run
when started.
a) Supply failure. Connect the power supply.
b) Fuses are blown. Replace fuses.
c) Motor-protective circuit breaker has tripped. Reactivate the motor-protective circuit breaker.
d) Thermal protection has tripped. Reactivate the thermal protection.
e) Main contacts in motor-protective circuit breaker
are not making contact or the coil is faulty.
Replace contacts or magnetic coil.
f) Control circuit is defective. Repair the control circuit.
g) Motor is defective. Replace the motor.
2. Motor-protective circuit
breaker trips
immediately when
power supply is
switched on.
a) One fuse/automatic circuit breaker is blown. Replace the fuse/cut in the circuit breaker.
b) Contacts in motor-protective circuit breaker are
faulty.
Replace motor-protective circuit breaker contacts.
c) Cable connection is loose or faulty. Fasten or replace the cable connection.
d) Motor winding is defective. Replace the motor.
e) Pump mechanically blocked. Remove the mechanical blocking of the pump.
f) Motor-protective circuit breaker setting is too
low.
Set the motor-protective circuit breaker correctly.
3. Motor-protective circuit
breaker trips
occasionally.
a) Motor-protective circuit breaker setting is too
low.
Set the motor-protective circuit breaker correctly.
b) Low voltage at peak times. Check the power supply.
4. Motor-protective circuit
breaker has not tripped
but the pump does not
run.
a) Check 1 a), b), d), e) and f).
5. Pump performance not
constant.
a) Pump inlet pressure is too low (cavitation). Check the suction conditions.
b) Suction pipe/pump partly blocked by impurities. Clean the suction pipe/pump.
c) Pump draws in air. Check the suction conditions.
6. Pump runs but gives no
water.
a) Suction pipe/pump blocked by impurities. Clean the suction pipe/pump.
b) Foot or non-return valve blocked in closed
position.
Repair the foot or non-return valve.
c) Leakage in suction pipe. Repair the suction pipe.
d) Air in suction pipe or pump. Check the suction conditions.
e) Motor runs in the wrong direction of rotation. Change the direction of rotation of the motor.
7. Pump runs backwards
when switched off.
a) Leakage in suction pipe. Repair the suction pipe.
b) Foot or non-return valve defective. Repair the foot or non-return valve.
8. Leakage in shaft seal. a) Shaft seal is defective. Replace the shaft seal.
9. Noise. a) Cavitation. Check the suction conditions.
b) Pump does not rotate freely (frictional
resistance) because of incorrect pump shaft
position.
Adjust the pump shaft.
Follow the procedure in fig. F, G or H at the end of
these instructions.
c) Frequency converter operation. See section 7.5 Frequency converter operation.
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