Fault Finding The Product - Grundfos S2 Instrucciones De Instalación Y Funcionamiento

10. Fault finding the product

Before attempting to diagnose any fault, read and
observe the safety instructions in section
instructions and requirements.
Fault
1. The pump does not start or
it stops without visible
cause.
2. The pump does not start or
it stops. The control panel
of the controller indicates
that the motor-protective
circuit breaker or protection
equipment has tripped out.
3. The pump runs, but does
not deliver the rated flow.
9.1 Safety
Cause
a) No power supply.
b) Moisture in the stator housing or in the
terminal box. The moisture switch interrupts
the supply voltage.
c) The water-in-oil sensor is not covered by oil.
The sensor interrupts the supply voltage.
a) Missing phase.
b) The pump is momentarily overloaded.
c) The impeller is jammed by impurities.
d) The motor-protective circuit breaker is not
set correctly.
e) The thermal switches have tripped out.
Insufficient motor cooling.
f) The moisture switch in the motor has tripped
out.
g) A power cable is defective.
h) Fluctuating voltage.
a) Wrong direction of rotation.
b) The impeller is worn.
c) The impeller is loose.
d) The pump or the pipes are clogged by
impurities.
e) The pump head is too high.
f) The valves are closed or blocked.
The non-return valve is not operating.
g) There is air in the pump or the inlet pipe.
h) The pumped liquid is too dense.
i) The pump is not properly connected to the
auto coupling.
j) There is leakage in the pipes.
Remedy
Re-establish the power supply, start the pump
manually and check contactor operation.
Contact an authorized service workshop.
Contact an authorized service workshop.
Re-establish all phases.
Let the pump cool down for approx. 10 minutes and
try to start again. In case the pump starts now, 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 have tripped. Wait for approx. 10 minutes
until the pump has cooled down, and try to start the
pump again. In case the pump does not start, the
overload relay has tripped and the pump needs
service. Contact an authorized service workshop.
Clean the impeller as required.
Set the motor-protective circuit breaker as required
in relation to the rated current.
Re-establish motor cooling.
Contact an authorized service workshop.
Contact an authorized service workshop.
Re-establish correct voltage supply. Permissible
deviation is ± 10 %.
Interchange two phases in the power supply to the
motor.
Adjust the impeller clearance.
If the impeller must be replaced, contact an
authorized service workshop.
Contact an authorized service workshop.
Clean the pump or the pipes as required.
Measure the differential pressure and compare the
value with the pump curve. Remove the blockage in
the outlet pipe.
Open, clean or replace the valves as required.
Vent the pump or the inlet pipe. Set a higher stop
level in the pit.
Dilute the pumped liquid.
Pump down the liquid level in pit. Lift out the pump
and relocate the pump on the auto coupling.
Repair or replace the pipes.
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