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Document
Preliminary 003
Access V4.X Configuration manual
30 (33)
2019-05-13
If a start signal is needed for a cooling unit or a magnetic valve for DX dehumidification, the digital
output signal “Start P1
-
Cooling” should be used. In this case, the “pump” stop delay should be
set to 0 s.
2.5 CO2 control
In applications with varying occupancy the fan speeds, mixing damper or both can be controlled by the
air quality as measured by a CO2 sensor.
With the CO2 function it’s possible to start and stop the fans, compensate the fan sp
eed and in
combination with mixing damper let in more outdoor air depending on the CO2 value.
Fan start/stop
Configuration > Functions > Function Activation > CO2 control > Fan start/stop function
When the function is activated with start/stop function and the CO2 value rises above settable start
value the fans will start at configured speed, if they are not already running.
Configuration > Functions > CO2 control >
Should the CO2 value continue to rise, the fan speed can increase if compensation with CO2 value is
configured (see
).
The fans will stop when the CO2 value falls to a settable hysteresis (default: 160 ppm) below the start
value.
Data & Settings > Demand control > CO2 >
Mixing damper function
Configuration > Functions > Function Activation > CO2 control > Mixing damper function
Activation of recirculation function is required for visual representation of the mixing damper in the
flowchart.
Configuration > Functions > Function
Activation > Recirculation > “Yes”
CO2 control by mixing damper involves configuration of temperature control sequences
“Recirculation
1” and “Recirculation 2”
.
Recirculation 1 shall be used as driving signal for Mixing damper.
Recirculation 2 shall be used as driving signal for Outdoor air (Fresh air) damper
Primary use for mixing function is to save energy by recirculating extracted air. Mixing damper would
open first followed by closing of outdoor air damper. Increased ratio of recirculated air would save more
energy but would also increase CO2. To keep CO2 at acceptable level the CO2 controller regulates back
(close mixing and open outdoor air dampers) to reduce mixing ratio.
The CO2 control option must be activated to make sequence output CO2 dependent.
Configuration > Functions > Function activation > Heating/Cooling sequences > Recirculation 1
> CO2 control > CO2 sequence 1