Fault
11. CU 301 indicates
"Overtemperature".
12. CU 301 indicates
"Overload".
13. CU 301 indicates
"Sensor defective".
14. The pump is
operating on and
off.
15. Excess pressure
for a short moment
at start of
consumption.
24
Possible cause
Remedy
The temperature sensor in the motor is sensing a temperature above the values
stated in the factory settings. See section
a)
Insufficient
Restore correct cooling of the motor. The flow velocity past
cooling of the
the motor must be at least 0.15 m/s.
motor.
a)
The pump is
worn or
The pump must be serviced.
blocked.
b)
The pump is too
large for the
Replace the pump or motor.
installed motor.
a)
The pressure
Check that the sensor is installed correctly.
sensor is
Check that the Grundfos GO Remote setting of the sensor
defective.
is correct.
Check the sensor values according to the pressure sensor
voltage chart. See
If the sensor type is 4-20 mA, measure the signal current.
If the current is above 2 mA, the sensor and wiring are OK.
If the current is below 2 mA, the sensor or wiring is
defective.
Replace defective parts.
Are the LED "Sensor defective" and the LED, pos. 1, on?
See section
•
•
a)
No
Check that the LED "No contact to pump" is on.
communication.
If so, CU 301 starts and stops the pump, based on the
sensor signal only. CU 301 has to be reset every 1000
stops.
Refer to fault 5 for remedy.
a)
Cut-in speed is
too high.
Reduce the cut-in speed, see section Dry-running stop at
reduced maximum pump speed:.
9. Technical
10. Pressure sensor voltage
5.8 Position of
Yes: The total load of 24 VDC from terminal 5 is above
100 mA.
Disconnect the sensor in order to determine if it is
defective.
Replace defective sensor.
No: The load is OK, but the CU 301 sensor input may be
defective.
data.
chart.
LEDs.