Fault Finding Chart - Grundfos CRK Series Installation And Operating Instructions Manual

14. Fault finding chart

Before starting work on 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 runs but gives no
liquid or pump capacity
is not constant.
6. Leakage in shaft seal.
7. Noise.
Cause
a) Supply failure.
b) Fuses are blown.
c) Motor starter overload has tripped out.
d) Thermal protection has tripped out.
e) Main contacts in motor starter are not making
contact or the coil is faulty.
f) Control circuit is defective.
g) Motor is defective.
a) One fuse/automatic circuit breaker 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 is too low.
a) Overload setting is too low.
b) Low voltage at peak times.
a) Supply failure.
b) Fuses are blown.
c) Thermal protection has tripped out.
d) Main contacts in motor starter are not making
contact or the coil is faulty.
a) Pump strainer partly blocked by impurities.
b) Liquid level in tank too low.
c) Pump draws in air.
a) Shaft seal is defective.
a) Cavitation occurs in the pump.
b) Pump does not rotate freely (frictional resistance)
because of incorrect pump shaft position.
c) Frequency converter operation.
Remedy
Connect the electricity supply.
Replace fuses.
Reactivate the motor protection.
Reactivate the thermal protection.
Replace contacts or magnetic coil.
Repair the control circuit.
Replace the motor.
Cut in the fuse.
Replace motor starter contacts.
Fasten or replace the cable connection.
Replace the motor.
Remove the mechanical blocking of the pump.
Set the motor starter correctly.
Set the motor starter correctly.
Check the electricity supply.
Connect the electricity supply.
Replace fuses.
Reactivate the thermal protection.
Replace contacts or magnetic coil.
Clean the strainer.
Increase the liquid level.
Check the suction conditions.
Replace the shaft seal.
Check the suction conditions.
Adjust the pump shaft.
See section 8.1 Frequency converter operation.
Subject to alterations.
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