Submittal Sheet

System applications
MAGNA3
3
10
3. Air handling unit
Constant flow
If the air flow temperature and thereby the heat output
is controlled by for example a motorised valve, the
system is typically operating with constant flow.
Therefore, we recommend that the pump operates in
the constant-flow control mode.
See Constant curve, page 21.
Variable flow
Normally, the distance between the pump and the air
handling unit is short, eliminating pressure losses
almost completely even if the flow varies. Therefore,
the constant-pressure control mode is suitable in this
type of application.
See Constant pressure, page 19.
4. Fan coil unit
Typically, fan coil units are situated at a considerable
distance from the pump.
Therefore, depending on how many fan coils are
operating and at which demand, large variations in
pressure loss will occur.
In such applications proportional pressure is the
recommended control mode.
If the pressure losses are unknown, you can choose
the AUTO
ADAPT
control mode, which will automatically
adjust the pump performance to the actual system
characteristic.
See Proportional pressure, page 19, and AUTO
ADAPT
,
page 17.
5. Radiator, two pipe
Since these applications have varying pressure losses
due to the distance between the pump and radiators,
we recommended that the pump operates in the
proportional-pressure control mode.
If the pressure losses are unknown, it is possible to
use the AUTO
ADAPT
control mode, which will
automatically adjust the pump performance to the
actual system characteristic.
See Proportional pressure, page 19, and AUTO
ADAPT
,
page 17.
6. Radiator, one pipe
In one-pipe radiator systems the flow is typically
constant, making the pressure losses constant as well.
Therefore, pumps in these applications are best suited
to operate in constant-pressure control mode.
Because these applications are often designed with a
specific differential temperature, it is possible to adjust
the constant-pressure setpoint until this differential
temperature is achieved.
See Constant pressure, page 19.
7. Underfloor/ceiling
In these systems the flow will vary depending on how
many rooms are in operation. However, since the
distance is short between the pump and manifold, to
which the pipes are connected, there is no variation in
pressure losses. Because of this the
constant-pressure control mode is the optimum choice.
See Constant pressure, page 19.
8D. Shunt/buffer
Constant temperature with internal sensor
If both the return temperature and the desired
minimum temperature back to the boiler are known,
you can calculate the required flow temperature
supplied by the shunt pump.
The calculated flow temperature is set directly on the
pump, when setting the control mode to constant
temperature.
See Constant temperature, page 20.
Constant temperature with external sensor
The minimum required return temperature back to the
boiler can be measured and controlled by the use of an
external temperature sensor placed close to the boiler.
This temperature can then be set directly on the pump
together with the constant-temperature control mode.
See Constant temperature, page 20.
Constant differential temperature
If the purpose of the boiler shunt pump is to secure
that a maximum differential temperature across a
boiler is not exceeded, choose the differential
temperature control mode. Despite load variations, the
differential temperature is then kept on a desired level.
This requires an additional temperature sensor.
8E. 'Primary only' system
These pumps are characterised by operating with
large variations in flow. Depending on the distance
between the pump and the last branch served by the
pump, either constant-pressure or
proportional-pressure control modes can be chosen.
Typically, proportional pressure will be the better
option if the pressure is above 5 m or the distance
between the pump and the last branch exceeds 10 m.
On the other hand, if pressure loss variations are
limited because all branches are connected closer to
the pump, constant pressure will be the recommended
control mode.
See Proportional pressure, page 19, andConstant
pressure, page 19.