Fault Finding Chart - Grundfos CR Serie Montage- Und Betriebsanleitung

11. Fault finding chart

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 back-
wards when switched
off.
8. Leakage in shaft seal.
9. Noise.
12. Disposal
Disposal of this product or parts of it must be carried out accord-
ing to the following guidelines:
1. Use the local public or private waste collection service.
2. In case such waste collection service does not exist or cannot
handle the materials used in the product, please deliver the
product or any hazardous materials from it to your nearest
Grundfos company or service workshop.
12
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) Check 1 a), b), d), e) and f).
a) Pump inlet pressure is too low (cavitation).
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 po-
sition.
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 is defective.
a) Shaft seal is defective.
a) Cavitation occurs in the pump.
b) Pump does not rotate freely (frictional resist-
ance) 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.
Check the suction conditions.
Clean the pump or suction pipe.
Check the suction conditions.
Clean the pump or suction pipe.
Repair the foot or non-return valve.
Repair the suction pipe.
Check the suction conditions.
Change the direction of rotation of the motor.
Repair the suction pipe.
Repair the foot or non-return valve.
Replace the shaft seal.
Check the suction conditions.
Adjust the pump shaft.
Follow the procedure in fig. F, G or H at the end of
these instructions.
See section 6.1 Frequency converter operation.
Subject to alterations.