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Preliminary 003
Access V4.X Configuration manual
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2019-05-13
2.3 Fan control
Fan control type
Configuration > Functions > Function activation > Fan control type >
Pressure
During pressure control, two separate signals are used for supply and extract air and two separate
analogue input signals for supply and extract air for pressure transmitters. The fan speeds are adjusted
to maintaining constant pressure.
Flow
Instead of giving a pressure setpoint value, it is possible to use an airflow volume value. The value from
the pressure transmitter is recalculated to a volume flow
Manual
Variable speed drive-controlled fans can be controlled at a fixed rotational speed. The rotational speed
is selected by setting a fixed output signal (0
–
100%). Values for normal and reduced speed can be
configured for each fan.
Fans that are run with a fixed output signal can also be compensated (see the section above). In this
mode, pressure sensors are not needed.
External
Two 0…10 V input signals are used for direct control of variable speed drive
-controlled fans. The signal is
received from e.g. a VAV unit. The signal
controls the fans 0…100% (0…10 V on the analogue output).
Pressure transmitters are not used in this control mode.
Supply air pressure and extract air fan slave
The rotational speed of the supply air fan is controlled by a pressure transmitter (”Pressure supply air”)
which is placed in the supply air duct. The extract air fan does not have a pressure transmitter, instead
you let the output for the extract air fan follow the control signal for the supply air fan. A scaling factor
can be added if the characteristics of the extract air fan are not the same as the characteristics of the
supply air fan. (Only pressure control of the supply air fan is possible using this function.) The extract air
fan will start directly at 50% after the start delay. Then the heating of the exchanger will work for this
operating mode as well. When the supply air fan starts, the extract air fan will be slave controlled by the
supply air flow.
Supply air pressure with extract air flow slave
The rotational speed of the supply air fan
is controlled by a pressure transmitter (“Pressure supply air”)
which is placed in the supply air duct. The extract air fan is controlled by the supply air flow, to achieve a
balanced ventilation. A pressure transmitter ("Flow supply air") which is placed in the supply air fan cone
gives a measured value of the present supply air flow. A corresponding pressure transmitter (”Flow
extract air”) is placed in the extract air fan cone and gives a measured value of the extract air flow.
The supply air flow is the setpoint used for control of the extract air fan. A scaling factor can be added if
the extract air fan does not have the same characteristics as the supply air fan.
Extract air pressure with supply air slave
The rotational speed of the extract air fan is
controlled by a pressure transmitter (“Pressure extract air”)
which is placed in the extract air duct. The supply air fan has no pressure transmitter. Instead, the supply