Grundfos MAGNA3 25-100 (N) User manual

GRUNDFOS DATA BOOKLET
MAGNA3
From Model D
Circulator pumps
50/60 Hz

Table of contents
2
MAGNA3
1. Product description 3
Type key 4
Model type 4
Pump heads in twin-head pumps 4
Performance range, MAGNA3 5
Performance range, MAGNA3 D single-head operation
5
Performance range, MAGNA3 D twin-head operation
6
2. Product range 7
3. System applications 9
Heating systems 9
Cooling systems 11
Solar-heating systems 13
4. Functions 14
Control modes: Quick overview 15
Operating modes 17
Control modes 17
Additional control mode features 22
Multipump modes 23
Flow estimation accuracy 24
Readings and settings on the pump 25
Communication 27
5. Operating conditions 32
General recommendations 32
Pumped liquids 33
Electrical data 34
6. Construction 35
7. Installation 37
Mechanical installation 37
Electrical installation 37
Connection to power supply, terminal-connected
versions 38
8. Curve conditions 40
Performance curves 40
Energy efficiency index (EEI) 40
QR code on the pump nameplate 40
Markings and approvals 41
9. Performance curves and technical data 42
10. Accessories 57
Insulating kits for air-conditioning and cooling systems
57
CIM modules 57
Grundfos GO 58
External Grundfos sensors 59
Cable for sensors 60
Blanking flange 60
Pipe connections 61
11. Product numbers 62
Single-head pumps 62
Twin-head pumps 62
12. Grundfos Product Center 63

Product description
MAGNA3 1
3
1. Product description
The Grundfos MAGNA3 model D circulator pumps are
designed for circulating liquids in systems with variable
flow requirements where you want to optimize the
setting of the pump duty point, thus reducing energy
costs.
Applications
• Heating systems
– main pump
– mixing loops
– heating surfaces
• air-conditioning and cooling systems
• domestic hot-water systems
• ground source heat-pump systems
• solar-heating systems.
The MAGNA3 circulator pump is perfect for both new
systems as well as for replacement. The pump is ideal
when operating in systems requiring an automated
adjustment of pressure. This pump range is the best
choice as it eliminates the need for expensive bypass
valves and similar components.
Furthermore, the pump is appropriate for systems with
hot-water priority as an external signal can
immediately force the pump to operate according to
the maximum curve, for example in solar-heating
systems. When using the pumps in domestic hot-water
systems, please observe local legislation regarding
pump house material. Grundfos strongly recommends
that you use stainless-steel pumps in domestic
hot-water applications to avoid corrosion.
Duty range
To ensure correct operation, it is important that the
duty points in the system match the duty range of the
pump.
Characteristic features
•AUTO
ADAPT.
•FLOW
LIMIT.
•FLOW
ADAPT - a combination of the AUTOADAPT
control mode and FLOWLIMIT function.
• Built-in Grundfos differential-pressure and
temperature sensor.
• Proportional-pressure control.
• Constant-pressure control.
• Constant-temperature control.
• Constant-curve duty.
• Maximum or minimum curve duty.
• Automatic night setback.
• Self-explanatory user interface with TFT display and
high quality silicone push-buttons.
• Heat energy monitor.
• Wireless multipump function.
The complete range is available for a maximum
system pressure of 175 psi (12 bar, 1.2 MPa), PN 12.
Benefits
• Low energy consumption due to the AUTOADAPT
function, allowing the pump to adjust automatically
to external factors, such as outside temperatures
and consumption patterns.
• Simple installation.
• No maintenance and long life.
• Operating log history.
• Easy and simple system optimization.
• External control and monitoring enabled via add-on
modules.
• No external motor protection required.
• Insulating shells for heating systems supplied with
single-head pumps.
• Wide temperature range due to thermal separation
of the control box and pump media.
TM05 8894 2813
Data MAGNA3 (N) Single-head
pumps
MAGNA3 D
Twin-head
pumps
Maximum flow rate 345 gpm
(78.5 m3/h)
484 gpm
(110 m3/h)
Maximum head 60 ft (18 m)
Maximum system pressure 175 psi (1.2 MPa) (12 bar)
Liquid temperature 14 to 230 °F (-10 to +110 °C)

Product description
MAGNA3
1
4
Type key
Model type
This data booklet covers MAGNA3 from model D. The
model version is stated on the nameplate. See fig. 1.
Fig. 1 Model type on pump nameplate
Pump heads in twin-head pumps
The twin-head pump housing has a flap valve on the
outlet side. The flap valve seals off the port of the idle
pump housing to prevent the pumped liquid from
running back to the inlet side. See fig. 2. Due to the
flap valve, there is a difference in the hydraulics
between the two heads. See fig. 3.
Fig. 2 Twin-head pump housing with flap valve
Fig. 3 Hydraulic difference between the two heads
Code Example MAGNA3 (D) 80 -120 (F) (N) 360
Type range
MAGNA3
D
Single-head pump
Twin-head pump
Nominal diameter (DN) of inlet and outlet ports [mm]
Maximum head [dm]
F
Pipe connection
Flange
N
Pump housing material
Cast iron
Stainless steel
Port-to-port length [mm]
TM06 7734 4017
TM06 1565 2514TM06 1566 2514
H
Q
Right pump head
Left pump head

Product description
MAGNA3 1
5
Performance range, MAGNA3
Fig. 4 Performance range, MAGNA3
Performance range, MAGNA3 D single-head operation
Fig. 5 Performance range, MAGNA3 D single-head operation
TM05 7654 2818
10 15 20 30 40 50 60 70 80 100 150 200 300 400
Q [US GPM]
6
8
10
12
15
20
30
40
50
60
[ft]
H
34567891010 20 30 40 50 60 Q [m³/h]
2
3
4
5
6
7
8
9
1010
[m]
H
MAGNA3
100-120
80-100
65-120
65-150
50-150
50-80
40-120
40-180
40-80
32-100
32-60
TM05 7655 2818
10 15 20 30 40 50 60 70 80 100 150 200 300 400
Q [US GPM]
10
15
20
25
30
40
50
[ft]
H
34567891010 20 30 40 50 60 Q [m³/h]
4
5
6
7
8
9
1010
[m]
H
MAGNA3 D
100-120
65-150
80-100

Product description
MAGNA3
1
6
Performance range, MAGNA3 D twin-head operation
Fig. 6 Performance range, MAGNA3 D twin-head operation
TM05 7656 2818
10 15 20 30 40 60 80 100 150 200 300 400 600
Q [US GPM]
10
15
20
25
30
40
50
[ft]
H
34567891010 20 30 40 50 60 70 80 90 Q [m³/h]
4
5
6
7
8
9
1010
[m]
H
MAGNA3 D
100-120
65-150
80-100

Product range
MAGNA3 2
7
2. Product range
Pump selection
All pumps have a "best point" (ηmax), indicating where
the pump is working most efficiently.
Consider the parameters in the following section.
Pump size
The system characteristic is used together with the
performance curve of the pump for sizing and correct
pump selection.
The selection of pump size must be based on the
following:
• required maximum flow
• maximum pressure loss in the system.
Refer to the system characteristics to determine the
duty point. See fig. 7.
Fig. 7 System characteristic
Operating conditions
You must check whether the operating conditions are
fulfilled, i.e:
• liquid quality and temperature
• ambient conditions
• minimum inlet pressure
• maximum operating pressure.
See also Operating conditions, page 32.
Closed valve operation
A MAGNA3 pump can operate at any speed against a
closed valve for several days without damage to the
pump. However, Grundfos recommends to operate at
the lowest possible speed curve to minimize energy
losses. There are no minimum flow requirements.
Note: Do not close inlet and outlet valves
simultaneously, always keep one open when the pump
is running. Media- and ambient temperatures must
never exceed the specified temperature range.
Cast iron Stainless steel (N) Page reference
115 V 230 V 115 V 230 V
Single-head pump models
MAGNA3 32-60 F (N) 98126820 98126822 43
MAGNA3 32-100 F (N) 98126824 98126826 44
MAGNA3 40-80 F (N) 98126800 98126828 98126802 98126830 45
MAGNA3 40-120 F (N) 98126804 98126832 98126806 98126834 46
MAGNA3 40-180 F (N) 98126808 98126836 98126810 98126838 47
MAGNA3 50-80 F (N) 98126812 98126840 98126814 98126842 48
MAGNA3 50-150 F (N) 98126816 98126844 98126818 98126846 49
MAGNA3 65-120 F (N) 98124696 98126848 98124702 98126850 50
MAGNA3 65-150 F (N) - 98126852 - 98126854 51
MAGNA3 80-100 F (N) - 98126856 - 98126858 53
MAGNA3 100-120 F (N) - 98126860 - 98126862 55
Twin-head pump models
MAGNA3 D 65-150 F - 98126863 - - 52
MAGNA3 D 80-100 F - 98126864 - - 54
MAGNA3 D 100-120 F - 98126865 - - 56
TM02 2040 3301
Q
Duty point
H

Product range
MAGNA3
2
8
Control modes
•AUTO
ADAPT (factory setting) which is suitable for
most installations.
•FLOW
ADAPT in systems where flow limitation is
required.
• Proportional-pressure control in systems with
considerable pressure losses in relation to large
flow variations.
• Constant-pressure control in systems with
insignificant pressure losses in relation to large flow
variations.
• Constant-temperature control in heating systems
with a fixed system characteristic, for example
domestic hot-water systems.
• Differential-temperature control in heating and
cooling systems.
• Constant-curve duty.
For further information on control and operating
modes, see Functions, page 14.
Automatic determination of the setpoint
If you know the duty point, you can enter the value on
the display when setting the pump. The pump then
automatically calculates the corresponding setpoint.
See fig. 8.
Fig. 8 Example of setpoint calculation based on a chosen
control mode and entered Q and H values
Communication
The Grundfos CIM modules (Communication Interface
Module) enable the MAGNA3 to connect to standard
fieldbus networks, offering substantial benefits:
• complete process control and monitoring
• modular design, prepared for future requirements
• based on standard functional profiles
• simple configuration and easy installation
• open communication standards
• reading warning and alarm indications.
For further details, see CIM modules, page 27.
Fig. 9 Example of a typical building management system
(BMS)
Note: A gateway is a device that facilitates the transfer
of data between two different networks based on
different communication protocols.
4.1.1.0.0.0 - 13A4.1.1.0.0.0 - 13B
TM05 2710 1112

System applications
MAGNA3 3
9
3. System applications
Heating systems
Fig. 10 Functional drawing of a heating system in a commercial building
TM07 0360 1218
MMMMM
T
T
M
2
4
A
BC
13
567
8
D
E
Pos. Description
1 Hot water
A Charging pump
B Recirculation
2 Hot water
C Recirculation
3 Air handling unit
4 Fan coil unit
5 Radiator two-pipe system
6 Radiator one-pipe system
7 Underfloor/ceiling
8 Boiler pump
D Shunt/buffer
E "Primary only" system

System applications
MAGNA3
3
10
Main pumps
Due to variations in the heat demand and flow rate, we
always recommend that you use speed-controlled
MAGNA3 pumps in a heating system, either
single-head pumps connected in parallel or twin-head
pumps. Single-head pumps connected in parallel have
several advantages. In alternating operation, each
pump is sized for 100 % flow. In this operating mode,
the second pump functions as backup for higher
reliability. As the pumps alternate, an equal number of
operating hours is ensured. Cascade operation of
pumps connected in parallel meets demands in
high-flow systems with low differential temperature
(∆t), and 50 % backup is ensured at the same time.
The twin-head pump saves installation time and costs.
By speed-controlling all pumps, you can obtain
maximum energy saving as the pumps will run at their
best efficiency point (BEP).
In a variable-flow system, we recommend that you
control the main pump in AUTOADAPT or proportional-
pressure mode.
However, if a load (e.g. a radiator) is far from the
pump, it can be advantageous to install a differential
pressure sensor across this load and use a setpoint for
differential pressure.
By using the FLOWADAPT function to ensure correct
balancing of the system, the need for pump throttling
valves can be reduced significantly.
The built-in heat energy monitor allows monitoring of
the heat energy consumption in the system only for
optimization purposes.
Air handler heating coils
The performance of heating surfaces is controlled by
the heating-water temperature and the flow rate. For
this purpose, we recommend that you install
variable-flow mixing loops at the heating surfaces. A
speed-controlled mixing-loop pump is ideal for
adaptation to the varying loads in a heating surface. In
this case, MAGNA3 will have full authority, making
external pump throttling valves superfluous.
Domestic hot water
For domestic hot-water circulation, the
constant-temperature control mode will ensure a
constant temperature in the recirculation pipe, without
the use of separate thermostatic valves, thus obtaining
maximum comfort.
Mixing loops
Due to variations in use, flow-pipe temperature and
heat demand in different parts of the building, the
heating system must be divided into zones controlled
by independent mixing loops. Due to the flow
variations, a speed-controlled mixing-loop pump will
have authority in the system. This will help obtain a
better hydraulic balance in the overall system. Speed
control of the pump via selection of a control mode,
depending on system application, ensures maximum
energy saving. See Control modes, page 17.
Advantages of using mixing loops:
• Reduced excessive differential pressure in the
system and hereby reduced risk of overflow
• increased control ability as the loop is provided with
the exact flow rate and temperature demand.

System applications
MAGNA3 3
11
Cooling systems
Fig. 11 Functional drawing of a cooling system in a commercial building
TM07 0358 1218
MM
M
T
T
1
2
3
4
67
5
AB
C
Pos. Description
1 Cooling tower
2 Cooling source
3 Primary/secondary system
A Primary pump
B Secondary pump
4 "Primary only" system
C Primary pump
5 Air handling unit
6 Fan coil unit
7 Underfloor/ceiling

System applications
MAGNA3
3
12
Primary and secondary pumps
Due to variations in the cooling demand and flow rate,
we recommend that you use speed-controlled
MAGNA3 pumps in a cooling system, either
single-head pumps connected in parallel or twin-head
pumps. Single-head pumps connected in parallel have
several advantages. In alternating operation, each
pump is sized for 100 % flow. In this operating mode,
the second pump functions as backup for higher
reliability. As the pumps alternate, an equal number of
operating hours is ensured. Cascade operation of
pumps connected in parallel meets demands in
high-flow systems with low differential temperature
(∆t), and 50 % backup is ensured at the same time.
The twin-head pump saves installation time and costs.
By speed-controlling all pumps, you can obtain
maximum energy saving as the pumps will run at their
best efficiency point (BEP).
In a variable-flow system, we recommend that you
control secondary pumps in AUTOADAPT or
proportional-pressure mode with a
differential-pressure sensor in the flow pipe with the
lowest pressure. This ensures maximum energy
saving.
The built-in heat energy monitor allows monitoring of
the heat energy consumption in the system.
Air handler cooling coils
The performance of cooling surfaces is controlled by
the cooling-water temperature and the flow rate. For
this purpose, we recommend that you install
variable-flow mixing loops at the cooling surfaces. A
speed-controlled mixing-loop pump is ideal for
adaptation to the varying loads in a cooling surface. In
this case, MAGNA3 will have full authority, eliminating
the need for external pump throttling valves. The
FLOWLIMIT ensures that the rated flow is never
exceeded.
Heat recovery system
The heat recovery system is of paramount importance
for the overall energy efficiency of an air-conditioning
or cooling system. Due to high load and temperature
variations in the system, it is important to use
variable-speed pumps in a heat recovery system.
Cooling tower
Due to chiller load variations and changes in the
temperature and moisture of the ambient air, the
cooling-tower flow rate is continuously changing. In
order to achieve maximum energy saving,
cooling-tower pumps have to be able to adapt to these
varying conditions. The pumps are controlled by a
temperature setpoint which is measured at the
condenser of the chiller. In this system, MAGNA3 will
have full authority, eliminating the need for pump
throttling valves. The FLOWLIMIT ensures that the
rated flow is never exceeded.
Mixing loops
Due to the risk of condensation, the flow-pipe
temperature through a cooling ceiling or floor must
never be lower than the dew point temperature of the
indoor air. The dew point temperature varies due to
variations in indoor moisture load and outdoor thermal
conditions. The result is that the cooling-water setpoint
has to be controlled. A mixing loop is ideal for
obtaining the correct temperature in order to adapt to
the varying setpoint.
Due to continuous cooling-load variations in the
building cooling zones, the cooling performance in
cooling ceilings and floors is controlled by motor
valves via zone control units, and therefore you must
always use a speed-controlled mixing-loop pump.

System applications
MAGNA3 3
13
Solar-heating systems
Fig. 12 Functional drawing of a solar-heating system
Main pumps
Solar-heating systems operate with very low flow rates
compared to other heating systems, however, with
relatively large pressure losses. With a conventional
circulator pump, the flow must be controlled with a
valve resulting in a significantly higher power
consumption. To achieve major reductions in energy
consumption, MAGNA3 is optimized with the
FLOWADAPT / FLOWLIMIT control mode for operation
specifically under these conditions.
Ground source heat pump systems (GSHP)
Fig. 13 Ground source heat pump system in a commercial
building
Main pumps
MAGNA3 is optimized for operation as a circulator
pump in a closed-loop pipe system which is buried in
the ground and filled with a mixture of water and
antifreeze agent. MAGNA3 is therefore ideal for large
ground source heat pump systems for commercial
buildings.
MAGNA3 is designed for pumping liquids down to +14
°F (-10 °C). The pump can use all known antifreeze
agent compositions.
It is important to note that all components are highly
energy-efficient. No other circulator pump performs
better in GSHP systems than MAGNA3 with the
FLOWADAPT / FLOWLIMIT control mode.
Use the benefit of the inputs and outputs of MAGNA3
to control the pump together with the heat pump.
Installation and commissioning
When installing MAGNA3, no external pressure sensor
or motor protection is required. Installation is simple
thanks to the built-in differential-pressure and
temperature sensor, which enables
proportional-pressure control without the installation of
a sensor in the system.
In systems where a differential pressure is desired at a
certain point of the system, you must install an external
pressure sensor. See Electrical data, page 34.
Pump selection is based on the required flow and
calculated pressure losses. We recommend that you
do not oversize the pump as it will lead to
unnecessarily high energy consumption.
MAGNA3 features the FLOWLIMIT function. In circuits
where MAGNA3 has full authority, the need for
external pump throttling valves is eliminated. The
FLOWLIMIT ensures that the rated flow is never
exceeded.
TM07 0367 1218
TM05 3422 1312
Pos. Description
1 Heat pump
T
T

Functions
MAGNA3
4
14
4. Functions
Page
Operating modes 17
Normal (control modes enabled) 17
Stop 17
Minimum curve 17
Maximum curve 17
Control modes 17
AUTOADAPT (factory setting) 17
FLOWADAPT 18
Proportional pressure 19
Constant pressure 19
Constant temperature 20
Differential temperature 20
Constant curve 21
Additional control mode features 22
FLOWLIMIT 22
Automatic Night Setback 23
Multipump modes 23
Alternating operation 23
Backup operation 23
Cascade operation 23
Readings and settings on the pump 25
Operating panel and display 25
Operating status 25
Pump performance 25
Warning and alarm 25
Heat energy monitor 26
Operating log 26
Grundfos Eye (status indicator) 26
Communication 27
Wireless Grundfos GO 27
Wireless GENIair connection 27
Pump information to BMS via CIM modules 27
Bus via GENIbus 28
Bus via LonWorks 28
Bus via PROFIBUS DP 28
Bus via Modbus RTU 28
Bus via BACnet MS/TP 28
Digital inputs 29
Relay outputs 30
Analog input for external sensor 30
External setpoint function 31

Functions
MAGNA3 4
15
Control modes: Quick overview
AUTOADAPT
• We recommend this control mode for most heating systems.
• During operation, the pump automatically makes the necessary adjustment
to the actual system characteristic.
FLOWADAPT
The FLOWADAPT control mode combines a control mode and a function:
• The pump is running in AUTOADAPT.
• The delivered flow from the pump will never exceed a selected FLOWLIMIT.
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.
H
Q
H
auto_min
A
1
A
3
A
2
H
set1
H
set2
H
Q
Qmax
90 %
Qmax
25 %
Hauto_min
H
fac
Qfac
H
Q
Hset
Hset
2
H
Q
H
Q

Functions
MAGNA3
4
16
For multipump modes, see Multipump modes, page 23.
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 curve
• The pump can be set to operate according to a constant curve, like an
uncontrolled pump.
• Set the desired speed in % of the maximum speed in the range from
minimum to 100 %.
H
Q
Δt
H
Q

Functions
MAGNA3 4
17
Operating modes
Normal
The pump runs according to the selected control
mode.
Note: You can select the control mode and setpoint
even if the pump is not running in Normal mode.
Stop
The pump stops.
Min.
You can use the minimum curve mode in periods
where a minimum flow rate is required.
This operating mode is for instance suitable for manual
night setback if automatic night setback is not desired.
Max.
You can use the maximum curve mode in periods
where a maximum flow rate is required.
This operating mode is for instance suitable for
hot-water priority.
You can select the normal, stop, min. and max.
operating modes directly by use of the built-in digital
inputs. See Connection to power supply,
terminal-connected versions, page 38.
Fig. 14 Maximum and minimum curves
Control modes
Factory setting
The pumps have been factory-set to AUTOADAPT
without automatic night setback, which is suitable for
most installations.
The setpoint has been factory-set. See Readings and
settings on the pump, page 25.
AUTOADAPT
We recommend the AUTOADAPT control mode for most
heating systems, especially in systems with relatively
large pressure losses in the distribution pipes, and in
replacement situations where the
proportional-pressure duty point is unknown.
This control mode has been developed specifically for
heating systems and we do not recommend it for
air-conditioning and cooling systems.
Characteristics and key benefits
• Automatically adjusts the pump to actual system
characteristics.
• Ensures minimum energy consumption and a low
noise level.
• Reduced operating costs and increased comfort .
Technical specifications
Fig. 15 AUTOADAPT control
The AUTOADAPT control mode is a form of
proportional-pressure control where the control curves
have a fixed origin, Hauto_min.
When you have enabled AUTOADAPT, the pump will
start with the factory setting, Hfac = Hset1,
corresponding to approximately 55 % of its maximum
head, and then adjust its performance to A1. See fig.
15.
When the pump registers a lower head on the
maximum curve, A2, the AUTOADAPT function
automatically selects a correspondingly lower control
curve, Hset2. If the valves in the system close, the
pump adjusts its performance to A3. See fig. 15.
Note: Manual setting of the setpoint is not possible.
TM05 2446 5111
H
Q
Max.
Min.
TM05 2452 1312
A1: Original duty point
A2: Lower registered head on the max. curve
A3: New duty point after AUTOADAPT control
Hset1: Original setpoint
Hset2: New setpoint after AUTOADAPT control
Hfac: See page 25
Hauto_min: A fixed value of 1.5 m
H
Q
H
auto_min
A
1
A
3
A
2
H
set1
H
set2

Functions
MAGNA3
4
18
FLOWADAPT
The FLOWADAPT control mode combines AUTOADAPT
and FLOWLIMIT, meaning that the pump runs
AUTOADAPT while at the same time ensuring that the
flow rate never exceeds the entered FLOWLIMIT value.
This control mode is suitable for systems where a
maximum flow limit is desired and where a steady flow
through the boiler in a boiler system is required. Here,
no extra energy is used for pumping too much liquid
into the system.
In systems with mixing loops, you can use FLOWADAPT
to control the flow in each loop.
Characteristics and key benefits
• The dimensioned flow for each zone (required heat
energy) is determined by the flow from the pump.
This flow rate can be set precisely in the
FLOWADAPT control mode without using throttling
valves.
• When the flow rate is set lower than the balancing
valve setting, the pump will ramp down instead of
losing energy by pumping against a balancing
valve.
• Cooling surfaces in air-conditioning systems can
operate at high pressure and low flow rate.
Note: The pump cannot reduce the flow rate on the
inlet side, but is able to control that the flow rate on the
outlet side is at least the same as on the inlet side, as
the pump has no built-in valve.
Technical specifications
Fig. 16 FLOWADAPT control
The factory setting of the FLOWADAPT is the flow rate
where the AUTOADAPT factory setting meets the
maximum curve. See fig. 16.
The typical pump selection is based on the required
flow rate and calculated pressure losses. The pump is
typically oversized by 30 to 40 % to ensure that it can
overcome the pressure losses in the system. Under
these conditions, the full benefit of AUTOADAPT cannot
be obtained.
To adjust the maximum flow rate of this "oversized"
pump, balancing valves are built into the circuit to
increase the resistance and thus reduce the flow rate.
The FLOWADAPT function reduces the need for a pump
throttling valve, see fig. 17, but does not eliminate the
need for balancing valves in heating systems.
Fig. 17 Reduced need for a pump throttling valve
TM05 3334 1312TM05 2685 1212
H
Q
Q
max
90 %
Q
max
25 %
H
auto_min
H
fac
Q
fac
Setting range

Functions
MAGNA3 4
19
Proportional pressure
Proportional pressure is suitable in systems with
relatively large pressure losses in the distribution pipes
and in air-conditioning and cooling systems:
• Two-pipe heating systems with thermostatic valves
and the following:
– very long distribution pipes
– strongly throttled pipe balancing valves
– differential-pressure regulators
– large pressure losses in the parts of the system
through which the entire amount of water flows,
for example a boiler, heat exchanger and
distribution pipe up to the first branching.
• Primary circuit pumps in systems with large
pressure losses in the primary circuit.
• Air-conditioning systems with the following:
– heat exchangers (fan coils)
– cooling ceilings
– cooling surfaces.
Characteristics and key benefits
• The head of the pump increases proportionally to
the flow rate in the system.
• Compensates for large pressure losses in the
distribution pipes.
Technical specifications
Fig. 18 Proportional-pressure control
The head against a closed valve is half the setpoint
Hset.
Constant pressure
A constant pressure is advantageous in systems with
relatively small pressure losses in the distribution pipes:
• Two-pipe heating systems with thermostatic valves:
– dimensioned for natural circulation
– small pressure losses in the parts of the system
through which the entire amount of water flows,
for example a boiler, heat exchanger and
distribution pipe up to the first branching.
– modified to a high differential temperature
between the flow pipe and the return pipe (for
example district heating).
• Underfloor heating systems with thermostatic
valves.
• One-pipe heating systems with thermostatic valves
or pipe balancing valves.
• Primary circuit pumps in systems with small
pressure losses in the primary circuit.
Characteristics and key benefits
• The pump pressure is kept constant, independent of
the flow in the system.
Technical specifications
Fig. 19 Constant-pressure control
TM05 2448 1212
H
Q
Hset
Hset
2
TM05 2449 0312
H
Q

Functions
MAGNA3
4
20
Constant temperature
This control mode is suitable in heating systems with a
fixed system characteristic, for example domestic
hot-water systems, where the control of the pump
according to a constant return-pipe temperature is
relevant.
Characteristics and key benefits
• The temperature is kept constant.
•FLOW
LIMIT is used to control the maximum
circulation flow rate.
Technical specifications
Fig. 20 Constant-temperature control
The inverse control for cooling application is available
from model B.
Temperature sensor
If the pump is installed in the flow pipe, install an
external temperature sensor in the return pipe of the
system. See fig. 21. Install the sensor as close as
possible to the consumer (radiator, heat exchanger,
etc.).
Fig. 21 Pump with an external sensor
If the pump is installed in the return pipe of the system,
you can use the internal temperature sensor. In this
case, install the pump as close as possible to the
consumer (radiator, heat exchanger, etc.).
Fig. 22 Pump with an internal sensor
Differential temperature
Select this control mode if the pump performance is to
be controlled according to a differential temperature in
the system where the pump is installed.
Characteristics and key benefits
• Ensures a constant differential temperature drop
across heating and cooling systems.
• Ensures a constant differential temperature
between the pump and the external sensor, see figs
23 and 24.
• Requires two temperature sensors, the internal
temperature sensor together with an external
sensor.
Technical specifications
Fig. 23 Differential temperature
TM05 2451 5111TM05 2615 0312
H
Q
tF
tR
TM05 2616 0312TM05 2451 5111
tF
tR
H
Q
Δt