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

9. Fault finding the product

Before attempting to diagnose any fault,
- read and observe the safety instructions in section
8. Servicing and maintaining the product
- make sure the power supply has been switched off
and that it cannot be accidentally switched on
- make sure that all rotating parts have stopped
moving.
Fault Cause
1. The pump does not a) No power supply.
start or stops without
visible cause.
2. The pump does not a) A phase is missing.
start or stops. The
b) The pump is momentarily overloaded.
control panel of the
controller indicates
c) The impeller is clogged by impurities.
that the motor-
d) The motor-protective circuit breaker is not set
protective circuit
breaker or protection
equipment has
e) The thermal switches have tripped due to
tripped.
f)
g) The motor cable is defective.
h) The voltage is fluctuating.
3. The pump runs, but a) Direction of rotation is wrong.
does not deliver the
b) The impeller is loose or worn.
rated flow.
c) The pump or pipes are blocked by impurities.
d) The pump head is too high.
e) The valves are closed or blocked. The non-
f)
g) The pumped liquid is too dense.
h) The pump is not properly connected to the
i)
j)
4. The pump starts, but a) The pump is clogged which causes the motor-
stops immediately.
b) The motor is overheated which causes
c) The level switches are out of adjustment or
correctly.
insufficient motor cooling.
The moisture switch in motor has tripped.
return valve is not operating.
There is air in the pump or the inlet pipe.
auto coupling.
The pipes are leaking.
The pump pit flushing system has been
inadvertently activated.
protective circuit breaker to trip.
thermal switches to trip.
defective.
Observe all regulations applying to pumps installed
in potentially explosive environments.
FM
Make sure that no work is carried out in potentially
explosive atmosphere.
Remedy
Re-establish the power supply. Start the pump manually
and check the contactor.
Re-establish all phases.
If the fault does not disappear automatically, find the
cause and remedy the fault.
Clean the impeller.
Set the motor-protective circuit breaker as required
according to the rated current.
Re-establish the motor cooling.
Contact an authorized service workshop.
Contact an authorized service workshop.
Re-establish correct voltage supply. Permissible
deviation is - 10 %/+ 10 %.
Exchange two phases to the motor.
Tighten or replace the impeller.
Clean as required.
Measure the differential pressure and compare the
value with the pump curve. Remove any blockage in
the outlet pipe.
Clean or replace the valves as required.
Vent the pump and the inlet pipe. Increase the stop
level in the pit.
Dilute the liquid.
Pump down the liquid level in the pit. Lift out the pump
and place the pump on the auto coupling again.
Repair the pipes.
Check the function and repair the flushing system as
required.
Clean the pump.
Allow the pump to cool. Clean the pump.
Clean or set the level switches or replace them as
required.
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