Grundfos CU 301 Manuel D'instructions page 24

7. The CU 301 indi-
cates "Overvoltage"
or "Undervoltage".
8. The CU 301 indi-
cates "Dry running".
9. The CU 301 indi-
cates "Speed reduc-
tion" and
"Undervoltage".
10. The CU 301 indi-
cates "Speed reduc-
tion" and "Overload".
11. The CU 301 indi-
cates "Overtempera-
ture".
12. The CU 301 indi-
cates "Overload".
(continued on the following page)
24
a) The supply voltage is
unstable or outside
the voltage range
specified for the in-
stalled motor type.
If the power consumption is lower than the dry-running stop setting and the motor
speed is within 1,000 rpm of programmed maximum speed, for an accumulated
period of 5 seconds, the pump will be stopped.
a) The pump perfor-
mance is too high for
the well yield.
b) The well screen is
blocked.
c) The dry-running stop
setting is incorrect.
Speed reduction is activated so as to maintain a reduced performance. When the
supply voltage falls so low that it can no longer supply the necessary current to
-1
maintain 3,000 min , the pump will be stopped.
a) The supply voltage is
unstable or lower
than the voltage
range specified for
the installed motor
type.
b) The pump is not of
the correct type.
c) The voltage drop in
the pump cable is too
great.
Speed reduction is activated so as to maintain a reduced performance.
a) The pump is worn or
blocked.
b) The pump is too large
for the installed mo-
tor.
The temperature sensor in the motor is sensing a temperature above the values
stated in 8. Technical data, factory settings.
a) Insufficient cooling of
the motor.
a) The pump is worn or
blocked.
b) The pump is too large
for the installed mo-
tor.
Check - possibly over a period of time - that the supply
voltage is according to the values below.
• Motor type 0.5 hp = 198-315 V
• Motor type 0.75 hp = 198-315 V
• Motor type 1.0 hp = 207-315 V
• Motor type 1.5 hp = 207-315 V.
Voltage range for 100-115 V motors:
• Motor type 0.5 hp = 90-180 V.
Note: As the voltage is detected at the motor, allow for
the voltage drop in the pump cable.
Replace the pump with a smaller pump or reduce the
pump performance, by lowering maximum speed, or re-
ducing set pressure.
Check the well capacity and restore water supply to the
well.
Check and correct the setting, see section 5.3.5 Dry-
running stop.
Restore correct supply voltage.
Install correct pump type.
Replace the pump cable with lower gauge wires.
The pump must be serviced.
Replace pump or motor.
Restore correct cooling of the motor. The flow velocity
past the motor should be at least 0.5 ft/s.
The pump must be serviced.
Replace pump or motor.