Grundfos CM series, Service Instructions Manual

Page: 20 / 30

Cause Remedy
Motor winding is defective. • Repair or replace the motor.
The pump is mechanically blocked. • Switch off the electricity supply, and clean or repair the pump.
The setting of the motor-protective circuit breaker is too low. • Set the motor-protective circuit breaker according to the rated
current of the motor (I
1/1
). See nameplate.
6.3 The motor-protective circuit breaker trips out occasionally.
Cause Remedy
The setting of the motor-protective circuit breaker is too low. • Set the motor-protective circuit breaker according to the rated
current of the motor (I
1/1
). See nameplate.
Periodic supply failure. • Check cables and cable connections for defects, and replace the
fuses.
Periodically low voltage. • Check cables and cable connections for defects and loose
connections.
• Check that the supply cable of the pump is correctly sized.
20
English (GB)