Fault Finding The Product - Grundfos DPK Montage- Und Betriebsanleitung

9. Fault finding the product

Before attempting to diagnose any fault, read and
observe the safety instructions in section
instructions and requirements.
For pumps with a sensor, start fault finding
by checking the status on the GU01 or
GU02 front panel. See installation and
operating instructions for GU01 or GU02.
Fault
The motor does not start,
the fuses blow or the
motor protector trips out
immediately.
Caution: Do not try to
start again.
The pump operates, but
the motor protector trips
after a short while.
The thermal switch of the
pump trips after a short
while.
The pump operates at
below-standard
performance and power
consumption.
The pump operates, but
gives no liquid.
The pump is clogged.
8.1 Safety
Cause
1. Power supply failure, short circuit
or earth leakage in the cable or the
motor winding.
2. The fuses blow due to use of wrong
type of fuse.
3. The impeller is blocked by
impurities.
4. Level pickup, float switch or
electrode is out of adjustment or
defective.
5. Motor phase malfunction.
1. Low setting of the thermal relay in
the motor protector.
2. Increased current consumption due
to large voltage drop.
3. The impeller is blocked by
impurities.
4. The direction of rotation is wrong.
1. The liquid temperature is too high.
Inadequate cooling.
2. The viscosity of the pumped liquid
is too high.
3. Fault in the electrical connection.
(Y-connection of pump to D-
connection results in considerable
undervoltage)
1. The impeller is blocked by
impurities.
2. The direction of rotation is wrong.
1. There is air in the pump.
2. The outlet valve is closed or
blocked.
3. The non-return valve is blocked.
1. The liquid contains large particles. Select a pump with a larger size of
2. A float layer has formed on the
surface.
DANGER
Electric shock
Death or serious personal injury
- Before starting any work on the product,
make sure that the power supply has
been switched off and that it cannot be
accidentally switched on.
Remedy
Have the cable and motor checked and
repaired by a qualified electrician.
Fit fuses of the correct type.
Clean the impeller.
Check the level pickups, float switches or
electrodes.
Inspect the motor and the connections.
Set the relay in accordance with the
specifications on the pump nameplate.
Measure the voltage between two motor
phases. Tolerance: - 5 %/+ 5 %.
Clean the impeller.
Check the direction of rotation and possibly
interchange any two phases in the power
supply. See section 4.2 Checking the
direction of rotation.
Improve cooling or lower the liquid
temperature.
Dilute the pumped liquid.
Check and correct the electrical
connection.
Clean the impeller.
Check the direction of rotation and possibly
interchange any two phases in the power
supply. See section 4.2 Checking the
direction of rotation.
Vent the pump twice.
Check the outlet valve and open and/or
clean it if necessary.
Clean the non-return valve.
passage.
Install a mixer in the pit.
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