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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.
• 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 power 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.
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.
DB68-05916A-09_IM_DVM Chiller Outdoor_EU_EN_.indd 29
2022-05-02 오전 9:00:01
