English (GB)
15
12. Fault finding
Warning
Before removing the terminal box cover,
switch off the power supply. Make sure
that the power supply cannot be
accidentally switched on.
Warning
The pumped liquid may be scalding hot
and under high pressure. Before any
removal or dismantling of the pump, the
system must therefore be drained, or the
isolating valves on either side of the pump
must be closed.
Fault
Cause
Remedy
1.
The pump does not run.
a)
Supply failure.
Switch on the switch.
Check cables and cable connections
for defects and loose connections.
b)
Motor protection tripped.
See 2. a), b), c), d), e).
c)
Control-current circuit
defective.
Repair or replace the control-current
circuit.
2.
Motor-protective circuit
breaker has tripped (trips
immediately when power
supply is switched on).
a)
Contacts of the
motor-protective circuit
breaker or magnet coil
defective.
Replace the contacts of the
motor-protective circuit breaker, the
magnet coil or the entire
motor-protective circuit breaker.
b)
Cable connection is loose or
faulty.
Check cables and cable connections
for defects, and replace the fuses.
c)
Motor winding is defective.
Repair or replace the motor.
d)
The pump is mechanically
blocked.
Switch off the power supply, and
clean or repair the pump.
e)
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.
3.
The motor-protective circuit
breaker trips occasionally.
a)
The setting of the
motor-protective circuit
breaker is too low.
See 2. e).
b)
Periodic supply fault.
See 2. b).
c)
Periodically low voltage.
Check cables and cable connections
for defects and loose connections.
Check that the power supply cable of
the pump is correctly sized.
4.
The motor-protective circuit
breaker has not tripped, but
the pump is inadvertently
out of operation.
a)
See 1. a), b), c) and 2. d).
5.
The pump performance is
unstable.
a)
Pump inlet pressure too low.
Check the inlet conditions of the
pump.
b)
Suction pipe is partly blocked
by impurities.
Remove and clean the suction pipe.
c)
Leakage in suction pipe.
Remove and repair the suction pipe.
d)
Air in suction pipe or pump.
Vent the suction pipe or pump.
Check the inlet conditions of the
pump.
6.
The pump performance is
unstable, and the pump is
noisy.
Self-priming pumps only:
a)
The differential pressure
across the pump is too low.
Close the tap gradually until the
discharge pressure is stable and the
noise has ceased.
Summary of Contents for CM
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