Control Functions; Quick Overview Of Control Modes - Grundfos MAGNA3 25-80 Installation And Operating Instructions Manual

7. Control functions

7.1 Quick overview of control modes

AUTO
ADAPT
• Recommended for most heating systems.
• During operation, the pump automatically makes the necessary
adjustment to the actual system characteristic.
FLOW
ADAPT
The FLOW control mode combines a control mode and a
ADAPT
function:
• The pump is running in AUTO
• The delivered flow from the pump will never exceed a selected
FLOW .
LIMIT
Proportional pressure
• Used in systems with relatively large pressure losses in the
distribution pipes.
• The head of the pump will increase proportionally to the flow in the
system to compensate for the large pressure losses in the
distribution pipes.
Constant pressure
• We recommend this control mode in systems with relatively small
pressure losses.
• The pump head is kept constant, independent of the flow in the
system.
Constant temperature
In heating systems with a fixed system characteristic, for example
domestic hot-water systems, the control of the pump according to a
constant return-pipe temperature is relevant.
Differential temperature
• Ensures a constant differential temperature drop across heating
and cooling systems.
• The pump will maintain a constant differential temperature
between the pump and the external sensor.
Constant flow
Note: Available for pumps with production code from 1838.
• The pump maintains a constant flow in the system independently
of the head.
• It is not possible to use an external sensor, instead, the pump uses
its internal sensor.
20
ADAPT
H
H
set1
A
1
H
auto_min H
set2
A A
3 2
H
25 % Q 90 % Q
max
H
fac
H
auto_min
Q
fac
H
H
set
H
set
2
H
H
Δt
H
H
Q
set
For further
information, see
section
7.3.2 AUTO .
ADAPT
Q
max
For further
information, see
section
7.3.3 FLOW .
ADAPT
Q
For further
information, see
section
7.3.4 Proportional
pressure.
Q
For further
information, see
section 7.3.5 Constant
pressure.
Q
For further
information, see
section 7.3.6 Constant
temperature.
Q
For further
information, see
section
7.3.7 Differential
temperature.
Q
For further
information, see
section 7.3.8 Constant
flow.
Q