Grundfos CU 301 Instrucciones De Instalación Y Operación página 22

Fault Possible cause
1 No light in the a)
front cover.
2 The pump does a)
not start. The
green indicator
light in the
on/off button is
on. No alarm is
indicated.
3 The pressure is a)
not constant.
4 The pump is a)
running
continuously.
22
The ribbon cable
connection is loose or
defective.
CU 301, the pressure
sensor 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.
Remedy
• Is the control indicator LED flashing?
If not, CU 301 is defective.
• Check that the ribbon cable connection is
secure.
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 7 psi 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 fault No 13 to troubleshoot the pressure
sensor.
If the pump has not started yet, proceed as
follows:
• Press and hold 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 4.2 System
Replace the pump, if necessary.
• Check the precharge pressure of the
diaphragm tank.
Remember to stop the system and drain the
tank before the pressure is checked.
• Ensure the diaphragm tank is a 2 gal tank.
• Check whether the sensor is positioned far
away from the tap.
If so, the pressure variations may be caused
by friction losses. See section
the pressure sensor.
• Try to lower the pressure setting. See section
4.2 System 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 using the on/off
button.
If this is not possible, CU 301 is defective.
Replace CU 301.
• See fault No 13 to troubleshoot the pressure
sensor.
sizing.
3.3 Positioning