Liqtec (Liqtec Function); Stop Function (Low-Flow Stop Function) - Grundfos CRE Series Installation And Operating Instructions Manual

Y
1
2
4 4
A
5
X: Time in seconds
Y: Pressure in bar
Pos. Parameter
1 Measured
2 Limit
3 Hysteresis band
4 Limit exceeded when
5 Detection delay
6 Resetting delay
Limit-exceeded
A
function active
- Action

9.22 LiqTec (LiqTec function)

Wiring example:
LiqTec
LT1 White wire
Brown and black wires
LT2 Blue wire
You can enable the function of the LiqTec sensors in
the display. A LiqTec sensor protects the pump
against dry running.
The function requires that a LiqTec sensor has been
fitted and connected to the pump.
3
X
6
Setting
Discharge pressure
5 bar
2 bar
below limit
5 seconds
8 seconds
-
Warning
When you have enabled the LiqTec function, it stops
the pump if dry running occurs. Restart the pump
manually if it has been stopped due to dry running.
Dry-running detection delay
You can set a detection delay to make sure that the
pump is given a chance to start up before the LiqTec
function stops the pump due to dry running.
Range: 0-254 seconds.
Factory setting
See the section on factory settings.
Related information
9.58 Factory settings for Grundfos GO

9.23 Stop function (Low-flow stop function)

You can set Low-flow stop function to these values:
• Not active
• Energy-optimal mode
• High-comfort mode
• User-defined mode (Customised operating
mode).
When the low-flow stop function is active, the flow is
monitored. If the flow becomes lower than the set
minimum flow (Q ), the pump changes from
min
continuous operation at constant pressure to start-
stop operation and stops if the flow reaches zero.
The advantages of enabling Low-flow stop function
are the following:
• no unnecessary heating of the pumped liquid
• reduced wear of the shaft seals
• reduced noise from operation.
The disadvantages of enabling Low-flow stop
function may be the following:
• The delivered pressure is not completely constant
as it fluctuates between the start and stop
pressures.
• The frequent starts and stops of the pump may in
some applications cause acoustic noise.
The impact of the above disadvantages very much
depends on the setting selected for the stop function.
The High-comfort mode setting minimises pressure
fluctuations and acoustic noise.
Select Energy-optimal mode if the main priority is to
reduce the energy consumption as much as possible.
Possible settings of the stop function:
• Energy-optimal mode The pump automatically
adjusts the parameters for the stop function so
that the energy consumption during the start-stop
operation period is minimised. In this case, the
stop function uses the factory-set values of the
minimum flow (Q ) and other internal
min1
parameters. See the figure below.
67