Automatic Restart; Dry-Running Stop; Maximum Speed; Cut-In Speed - Grundfos CU 301 Installation And Operating Instructions Manual

5.3.4 Automatic restart

Set the automatic restart time from stop, caused by
an alarm, to restart attempt.
The following settings are available:
Time
• 0:05
• "–" (not active)
• 1, 2, ... 30 m (1 min. intervals)
30, 45, 1 h, ... 2 h (15 min. intervals)
2 h 30 m, 3 h, ... 4 h (30 min. intervals).
Double
• Yes
• No.
When "Yes" is selected, the restart time set will be
doubled automatically for every 10 motor stops
caused by an alarm. The time is doubled up to a stop
time of 4 hours.
After 10 hours of operation without an alarm, the
restart time is automatically set to:
• the time set in the "Time" field or
• 5 min. (factory setting) if no setting was made in
the "Time" field.

5.3.5 Dry-running stop

The dry-running stop value is factory-set.
The factory setting depends on the power rating of
the motor.
The following settings are default:
• Motor type 0.5 hp, dry-running stop = 300 W.
Note: For 10 SQE 160 and 10 SQE 160 N pumps,
the value is 550 W.
• Motor type 0.75 hp, dry-running stop = 680 W.
• Motor type 1.0 hp, dry-running stop = 800 W.
• Motor type 1.5 hp, dry-running stop = 900 W.
When the dry-running protection is to be active, the
minimum value of the pump power input must be set
in this display.
Setting range: 0-2500 W (10 W intervals).
18
Relation to other displays
The actual pump power input can be read in display
5.2.5 Power input and power consumption.
If the maximum pump speed has been reduced in
display 5.3.6 Maximum speed, the dry-running stop
value must be changed.

5.3.6 Maximum speed

Set the maximum speed.
Setting range: 3,000-10,700 min
vals).
Dry-running stop at reduced maximum pump
speed
If the maximum pump speed has been reduced, the
dry-running stop value in display 5.3.5 Dry-running
stop must be changed.
Calculating the minimum power limit
Note: The calculated value is used in display
5.3.5 Dry-running stop.
Note: If the pump is worn, a renewed calculation of
the minimum power limit may be required.
Step Action
Start the pump against closed discharge
1
valve.
Read the power input (P
2
5.2.5 Power input and power consumption.
Calculate the minimum power limit as
3 follows:
Power limit [W] = P

5.3.7 Cut-in speed

In the case of an oversized pump or drastically
changing water levels, this function may cause an
excess pressure, at start-up, in relation to the
desired discharge pressure. The cut-in speed can
therefore be lowered to compensate.
Setting range: 3,000-10,700 min
-1
(100 min intervals).
-1
-1 (100 min inter-
) in display
1
· 0.9.
1
-1 (8,200 min -1 )