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

1
2
4 4
A
5
Limit exceeded (example)
Pos. Setting parameter
1 "Measured"
2 "Limit"
3 "Hysteresis band"
4 "Limit exceeded when"
5 "Detection delay"
6 "Resetting delay"
A "Limit exceeded function active"
- "Action"
Factory setting
See the section on factory settings.
Related information
8.9 "Signal relays" 1 and 2 ("Relay outputs")
9.2 Factory settings

8.16 "LiqTec" ("LiqTec function")

Pump variant
CME
CRE, CRIE, CRNE, CRKE, SPKE,
MTRE
You can enable the function of the LiqTec sensors in this 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.
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 in order 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
9.2 Factory settings
3
T[s]
6
Setting
Outlet pressure
5 bar
2 bar
Below limit
5 seconds
8 seconds
-
Warning
"LiqTec"
("LiqTec function")
●
●

8.17 "Stop function" ("Low-flow stop function")

Pump variant
CME
CRE, CRIE, CRNE, CRKE, SPKE, MTRE
You can set the "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
changes from continuous operation at constant pressure to start-
stop operation and stops if the flow reaches zero.
The advantages of enabling the "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 the "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/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 minimizes 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 minimized. In this case,
the stop function uses the factory-set values of the minimum
flow (Q ) and other internal parameters. See the figure
min1
below.
• "High-comfort mode": The pump automatically adjusts the
parameters for the stop function so that the disturbances during
the start-stop operation period are minimized. In this case, the
stop function uses the factory-set values of the minimum flow
(Q ) and other internal parameters. See the figure below.
min2
• "User-defined mode" ("Customised operating mode"): The pump
uses the parameters set for ΔH and minimum flow (Q
respectively for the stop function. See the figure below.
H
1
△ H
2
Q min2 Q min1
Q min3
Difference between start and stop pressures (ΔH) and minimum
flow rate
"Stop function"
("Low-flow stop
function")
●
●
), the pump
min
min3)
Q
49