Fault Finding The Product - Grundfos TP Serie Instrucciones De Instalación Y Funcionamiento

10. Fault finding the product

Warning
Before removing the terminal box cover
and before removal/dismantling the pump,
make sure that the power supply has been
switched off and that it cannot be
accidentally switched on.
Make sure that the escaping liquid does
not cause injury to persons or damage to
the motor or other components.
In hot-liquid installations, pay special
attention to the risk of injury caused by
scalding hot liquid.
In cold-liquid installations, pay special
attention to the risk of injury caused by the
cold liquid.
Fault
1. Motor does not run when
started.
2. Motor protection device trips
immediately when power
supply is switched on.
3. Motor protection device trips
occasionally.
4. Motor protection device has
not tripped 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 the shaft seal.
Cause
a) Power supply failure.
b) Fuses blown.
c) Motor protection device has tripped.
d) Main contacts in motor protection device are not making contact or
the coil is faulty.
e) Control circuit fuses are defective.
f) Motor is defective.
a) Power supply failure.
b) Contacts in motor protection device are faulty.
c) Cable connection is loose or faulty.
d) Motor winding is defective.
e) Pump is 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.
a) Check the power supply.
b) Check fuses.
c) Check the main contacts in the motor protection device and coil.
d) Check the control circuit.
a) Pump inlet pressure is too low.
b) Inlet pipe/pump partly blocked by impurities.
c) Pump draws in air.
a) Inlet pipe/pump blocked by impurities.
b) Foot or non-return valve blocked in closed position.
c) Leakage in the inlet pipe.
d) Air in inlet pipe or pump.
e) Motor rotates in the wrong direction.
a) Leakage in the inlet pipe.
b) Foot or non-return valve defective.
c) Foot or non-return valve blocked in open or partly open position.
a) Pump shaft position is incorrect.
b) Shaft seal is defective.
17