Fault Finding - Grundfos SL1 Serie Instructions D'installation Et D'utilisation

11. Fault finding

Warning
Before attempting to diagnose any fault, make sure that the fuses have been removed or the mains switch has been
switched off. It must be ensured that the power supply cannot be accidentally switched on.
All rotating parts must have stopped moving.
Warning
FM
All regulations applying to pumps installed in potentially explosive environments must be observed.
It must be ensured that no work is carried out in potentially explosive atmosphere.
For pumps with sensor, start fault finding by checking the status on the IO 111 front panel.
Note
See installation and operating instructions for IO 111.
Fault Cause
1. Motor does not a) Supply failure; short-circuit; earth-leakage fault in
start. cable or motor winding.
Fuses blow or
b) Fuses blow due to use of wrong type of fuse.
motor-protective
c) Impeller blocked by impurities.
circuit breaker
d) Air bells, float switches or electrodes out of
trips out
adjustment or defective.
immediately.
Caution: Do not
e) Moisture in the stator housing (alarm).*
start again!
The IO 111 interrupts the supply voltage.
f) The WIO sensor is not covered by oil (alarm).*
The IO 111 interrupts the supply voltage.
g) *Stator insulation resistance too low.
2. Pump operates, a) Low setting of thermal relay in motor-protective
but motor- circuit breaker.
protective circuit
b) Increased current consumption due to large
breaker trips out
voltage drop.
after a short while.
c) Impeller blocked by impurities. Increased current
consumption in all three phases.
d) Wrong direction of rotation.
3. The thermal switch a) Too high liquid temperature.
of the pump trips
b) Too high viscosity of the pumped liquid.
out after a short
c) Wrong electrical connection. (If the pump is star-
while.
connected to a delta connection, the result will be
very low undervoltage).
4. Pump operates at a) Impeller blocked by impurities.
below-standard
b) Wrong direction of rotation.
performance and
power
consumption.
5. Pump operates, a) Discharge valve closed or blocked.
but gives no liquid.
b) Non-return valve blocked.
c) Air in pump.
6. High power a) Wrong direction of rotation.
consumption
(SLV).
b) Impeller blocked by impurities.
7. Noisy operation a) Wrong direction of rotation.
and excessive
vibrations (SL1).
b) Impeller blocked by impurities.
8. Pump clogged. a) The liquid contains large particles.
b) A float layer has formed on the surface of the liquid. Install a mixer in the tank.
* Applies only to pumps with sensor and with IO 111.
Remedy
Have the cable and motor checked and repaired by a
qualified electrician.
Fit fuses of the correct type.
Clean the impeller.
Readjust or replace the air bells, float switches or
electrodes.
Replace the O-rings, the shaft seal and moisture switch.
Check, and possibly replace, the shaft seal, fill up with
oil and reset the IO 111.
Reset alarm on IO 111. See installation and operating
instructions for IO 111.
Set the relay in accordance with the specifications on
the nameplate.
Measure the voltage between two motor phases.
Tolerance: - 10 %/+ 6 %. Reestablish correct voltage supply.
Clean the impeller.
Check the direction of rotation and possibly interchange
any two of the phases in the incoming supply cable.
See section 9.3 Direction of rotation.
Reduce the liquid temperature.
Dilute the pumped liquid.
Check and correct the electrical installation.
Clean the impeller.
Check the direction of rotation and possibly interchange
any two of the phases in the incoming supply cable.
See section 9.3 Direction of rotation.
Check the discharge valve and possibly open and/or
clean it.
Clean the non-return valve.
Vent the pump.
Check the direction of rotation and possibly interchange
any two of the phases in the incoming supply cable.
See section 9.3 Direction of rotation.
Clean the impeller.
Check the direction of rotation and possibly interchange
any two of the phases in the incoming supply cable.
See section 9.3 Direction of rotation.
Clean the impeller.
Select a pump with a larger size of passage.
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