Fault Finding The Product; Fault Finding With Grundfos Go Remote - Grundfos CU 301 Notice D'installation Et De Fonctionnement

7. Fault finding the product

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.
- The fault finding and service must be
carried out by qualified persons.
Fault
1. No light in the front
cover.
2. The pump does not
start. The green
indicator light in the
on/off button is on.
No alarm is
indicated.
3. The pressure is not
constant.
4. The pump is
running
continuously.
20
Possible cause Remedy
a) The multicore •
connection is
misplaced or
•
defective.
a) CU 301 or the •
pump is
defective.
•
•
•
a) The pump is not •
of the correct
type or the
precharge
pressure of the
•
diaphragm tank
is incorrect.
•
a) The pump •
cannot deliver
the pressure
set. CU 301 or
the sensor is
•
defective.
•
•
•

7.1 Fault finding with Grundfos GO Remote

The easiest way is to fault find the product is to use
Grundfos GO Remote. Error codes can be extracted
from the unit and read on the device.
Is the control indicator LED flashing?
If not, CU 301 is defective.
Check that the multicore cable connection is OK.
If so, CU 301 is defective. Contact Grundfos.
Check that the control indicator LED is flashing.
If not, CU 301 is defective.
Check that the system pressure is 0.5 bar below the
pressure setting.
If so, the pump is supposed to start. Open a tap to be
sure.
If the pump starts, the system is probably OK.
The system pressure can be read on the pressure
gauge.
See point 13. to check the pressure sensor.
If the pump has not started yet, proceed as follows:
Press the on/off button for 5 seconds.
If the pump starts, CU 301 or the sensor may be
defective.
Note that the pressure is not controlled and may rise to
a high level.
Check that the LED for Max. speed or Min. speed is on.
If so, this indicates that the pump has reached a limit.
See section sizing. Replace the pump, if
3.2 System
necessary.
Check the precharge pressure of the diaphragm tank.
Remember to stop and drain the system before the
pressure is checked.
Check whether the sensor is positioned far away from
the tap.
If so, the pressure variations may be caused by friction
losses. See section
2.3 Positioning the pressure
sensor.
Try to lower the pressure set. See section
sizing.
Note that the pump may run for about 15 to 20 seconds
before it stops.
Check that the control indicator LED is flashing.
Check that the pipe end of the sensor is not blocked.
If so, remove the blockage.
Try to stop the pump by means of the on/off button.
If this is not possible, CU 301 is defective. Replace CU
301.
See point 13. to check the pressure sensor.
3.2 System