Grundfos magna3 - FLOW LIMIT Feature

Functions
MAGNA3
4
22
Additional control mode features
MAGNA3 offers additional features for the control
modes to meet specific demands.
FLOW
LIMIT
The feature is an integrated part of the FLOW
ADAPT
control mode, but is also advantageous in:
• proportional-pressure mode
• constant-pressure mode
• constant-temperature mode
• constant-curve mode.
Characteristics and key benefits
• A control mode feature that, when activated,
ensures that the rated maximum flow is never
exceeded.
• By enabling FLOW
LIMIT
in systems where MAGNA3
has full authority, the rated flow is never exceeded,
thus eliminating the need for throttling valves.
Technical specifications
Fig. 27 FLOW
LIMIT
The setting range for the FLOW
LIMIT
is 25 to 90 % of
the Q
max
of the pump.
Note: Do not set the FLOW
LIMIT
lower than the
dimensioned duty point.
In the flow rate range between 0 and Q
limit
, the pump
will run according to the selected control mode.
When Q
limit
is reached, the FLOW
LIMIT
function will
reduce the pump speed to ensure that the flow rate
never exceeds the FLOW
LIMIT
set, no matter if the
system requires a higher flow rate due to an increased
resistance in the system. See figs 28, 29 and 30.
Fig. 28 Proportional-pressure control with FLOW
LIMIT
Fig. 29 Constant-pressure control with FLOW
LIMIT
Fig. 30 Constant curve with FLOW
LIMIT
TM05 2445 1312
H
Q
Q
max
Q
limit
90 %
Q
max
25 %
Setting range
TM05 2543 0412TM05 2444 0312TM05 2542 0412
H
Q
2
H
set
H
set
MJNJU
Normal proportional-pressure
duty point
FLOW
LIMIT
duty point
H
Q
H
set
MJNJU
Normal constant-pressure
duty point
FLOW
LIMIT
duty point
H
Q
MJNJU
Normal constant-curve
duty point
FLOW
LIMIT
duty point