Grundfos CU 301 Instrucciones De Instalación Y Funcionamiento página 23

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 Possible cause
1 No light in the front a)
cover.
2 The pump does not a)
start. The green
indicator light in the
on/off button is on.
No alarm is
indicated.
3 The pressure is not a)
constant.
4 The pump is a)
running
continuously.
The multicore connection is
misplaced or defective.
CU 301 or the pump is
defective.
The pump is not of the correct
type or the precharge
pressure of the diaphragm
tank is incorrect.
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.
Remedy
• 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 3.2 System sizing. Replace the pump, if 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
• 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.
sensor.
3.2 System
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