Grundfos CU 301 Instrucciones De Instalación Y Funcionamiento página 24

Fault Possible cause
5 CU 301 indicates a)
"No contact to
pump".
b)
c)
d)
e)
f)
6 Even after a)
replacement, CU
301 indicates "No
contact to pump".
24
The motor is not an MSE 3.
The pump cable is longer than
200 metres.
Cable breakage.
Cross communication with
adjacent CU 301.
The CU 301 communication
part is defective.
The MSE 3 motor
communication part is
defective.
Numbering of SQE pump and
CU 301 is different.
Remedy
If the pump has already worked satisfactorily with a CU 301 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.
Reduce the length of the pump cable.
Switch off the mains supply to CU 301.
Switch on the mains supply again. The pump is now
connected directly to the mains supply without interference
from CU 301.
Does the motor start?
• Yes: The cable is OK. Go to point d).
• No: Switch off the mains supply again. Remove the cable
and cable plug from the motor and carry out megging of
the cable including the plug.
Is the cable OK?
• Yes: The motor is defective. Replace the motor.
• No: Replace the cable.
If another CU 301 is installed:
• Ensure each unit has a unique number assigned. See
section 5.3.11 Number.
• If pump cables run parallel to each other, physically
separate them by 12-14 inches or rewire using shielded
cable.
Are the three CU 301 supply board LEDs in pos. 2, 3 and 4 on
and is the control indicator LED flashing? See section
4.8 Position of LEDs.
• Yes:
The mains supply is OK.
Give 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 mains supply must not
have the same number!
Is the LED "No contact to pump" of the new CU 301 also on?
• Yes: CU 301 is OK.
• No: CU 301 which was removed is defective.
As a consequence of the above-mentioned checks, replace
the MSE 3 motor.
If an SQE/CU 301 system has been given a number, this
number is stored in both SQE and CU 301.
A new CU 301 will probably not have a number corresponding
to the number stored in SQE. Therefore, "No contact to pump"
is indicated even if there is no fault.
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 mains supply must not
have the same number!