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.
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.
c) Frequency converter operation.
See section
7.5 Frequency converter operation
.
Summary of Contents for CRT
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