9. Fault finding the product
Before diagnosing any fault, read and observe the safety instructions.
Fault
Cause
Remedy
The pump does not start or it stops
without visible cause.
No power supply.
Re-establish the power supply, start
the pump manually and check con-
tactor operation.
Moisture in the stator housing or in
the terminal box. The moisture
switch interrupts the supply voltage.
Contact an authorised service work-
shop.
The WIO sensor is not covered by
oil. The sensor interrupts the supply
voltage.
Contact an authorised service work-
shop.
The pump does not start or it stops.
The control panel of the controller
indicates that the motor-protective
circuit breaker or protection equip-
ment is tripped out.
Missing phase.
Re-establish all phases.
The pump is overloaded.
Let the pump cool down for approxi-
mately 10 minutes and start it
again. In case the pump starts, the
first stop was caused by a tripping
thermal switch.
If the fault occurs again, find the
cause of the overload.
Check the control panel fuses and
switch them on in case they are
tripped. Wait for approximately 10
minutes until the pump is cooled
down, and start it again. In case the
pump does not start, the overload
relay is tripped and the pump needs
service. Contact an authorised
service workshop.
The impeller is jammed by impuri-
ties.
Clean the impeller as required.
The motor-protective circuit breaker
is set incorrectly.
Set the motor-protective circuit
breaker as required.
The thermal switches are tripped
out. Insufficient motor cooling.
Re-establish motor cooling.
The moisture switch in the motor is
tripped out.
Contact an authorised service work-
shop.
A power cable is defective.
Contact an authorised service work-
shop.
Fluctuating voltage.
Re-establish correct voltage supply.
The permissible deviation is ± 10
%.
The pump runs but does not deliver
the rated flow.
Wrong direction of rotation.
Interchange two phases in the pow-
er supply to the motor.
The impeller is worn.
Adjust the impeller clearance.
If the impeller must be replaced,
contact an authorised service work-
shop.
38
English (GB)
Summary of Contents for ST-55-520
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