Grundfos CU 301 Notice D'installation Et De Fonctionnement page 22

Fault
5. CU 301 indicates
"No contact to
pump".
22
Possible cause Remedy
a) The motor is not If the pump has already worked satisfactorily with a CU 301
an MSE 3. or a CU 300, the motor can be expected to be an MSE 3.
There is no technical way of determining the motor type.
The only way is to read the nameplate engraved in the
motor sleeve.
b) The pump cable
is longer than Reduce the length of the pump cable.
956 feet.
c) Cable Switch off the power supply to CU 301.
breakage. Connect the motor conductors directly to the power supply.
Switch on the power supply again. The pump is now
connected directly to the power supply without interference
from CU 301.
Does the motor start?
•
•
Is the cable OK?
•
•
Note that a megohmmeter ('megger') or other high voltage
device must never be used during troubleshooting of an SQ
pump. This will damage the internal electronics.
d) Cross If another CU 301 is installed:
communication •
with adjacent
CU 301.
•
e) The CU 301 Are the three CU 301 supply board LEDs in pos. 2, 3 and 4
communication on and is the control indicator LED flashing? See section
part is defective. 5.8 Position of
•
The power supply is OK.
Assign the system a new number.
If this does not work, CU 301 or the motor communication
part is defective.
Replace CU 301 and give the new system a number
between 1 and 64 in order to obtain correspondence
between the numbering of the SQE pump and CU 301.
Note that two systems on the same power supply must not
have the same number!
Is the LED "No contact to pump" of the new CU 301 also
on?
•
•
f) The MSE 3
motor As a consequence of the above-mentioned checks, replace
communication the MSE 3 motor.
part is defective.
Yes: The cable is OK. Go to point d).
No: Switch off the power supply again. Remove the
cable and cable plug from the motor and ohm out the
cable including the plug.
Yes: The motor is defective. Replace the motor.
No: Replace the cable.
Ensure each unit has a unique number assigned. See
section 6.3.11 Number.
If pump cables run in parallel to each other, physically
separate them by 12-14 inches or rewire using a
shielded cable.
LEDs.
Yes:
Yes: CU 301 is OK.
No: CU 301 which was removed is defective.