Fault Finding Chart - Grundfos SE1 50 Montage- Und Betriebsanleitung

11. Fault finding chart

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.
Fault
1. Motor does not start.
Fuses blow or motor-protective
circuit breaker trips out
immediately.
Caution: Do not start again!
2. Pump operates, but
motor-protective circuit breaker
trips out after a short while.
3. The thermal switch of the pump
trips out after a short while.
4. Pump operates at
below-standard performance
and power consumption.
5. Pump operates, but gives no
liquid.
6. High power consumption
(SEV).
7. Noisy operation and excessive
vibrations (SE1).
8. Pump clogged.
* Applies only to pumps with sensor and with IO 111.
Cause
a) Supply failure; short-circuit; earth-leakage
fault in cable or motor winding.
b) Fuses blow due to use of wrong type of fuse. Fit fuses of the correct type.
c) Impeller blocked by impurities.
d) Air bells, float switches or electrodes out of
adjustment or defective.
e) Moisture in the stator housing (alarm).
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.*
a) Low setting of thermal relay in
motor-protective circuit breaker.
b) Increased current consumption due to large
voltage drop.
c) Impeller blocked by impurities. Increased
current consumption in all three phases.
d) Wrong direction of rotation.
a) Too high liquid temperature.
b) Too high viscosity of the pumped liquid.
c) Wrong electrical connection. (If the pump is
star-connected to a delta connection, the
result will be very low undervoltage).
a) Impeller blocked by impurities.
b) Wrong direction of rotation.
a) Discharge valve closed or blocked.
b) Non-return valve blocked.
c) Air in pump.
a) Wrong direction of rotation.
b) Impeller blocked by impurities.
a) Wrong direction of rotation.
b) Impeller blocked by impurities.
a) The liquid contains large particles.
b) A float layer has formed on the surface of
the liquid.
Warning
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.
Remedy
Have the cable and motor checked and repaired
by a qualified electrician.
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
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
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
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
Clean the impeller.
Select a pump with a larger size of passage.
Install a mixer in the pit.
rotation.
rotation.
rotation.
rotation.
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